Assessment of acute abdomen

Overview 
Theory 
Emergencies 
Diagnosis 
Resources 

Common

Adhesions

History

history of abdominal or pelvic surgery; intermittent, cramp-like abdominal pain; nausea and/or vomiting, feculent vomiting, constipation, absence of flatus, history of intra-abdominal malignancy, including ovarian or colon cancer

Exam

high-pitched (hyperactive) bowel sounds with rushes, or absent bowel sounds; distended abdomen, tenderness to abdominal palpation, involuntary guarding; pyrexia; tachycardia; tympany on percussion; presence of abdominal scars

1st investigation

CT of abdomen and pelvis with oral and intravenous contrast:
may see dilated loops of proximal bowel with collapsed loops posterior to site of obstruction
plain abdominal x-rays:
may see dilated loops of bowel
More
CT preferred if available, because it gives more information about the level and cause of the obstruction.[63]
Images of both flat (supine) and upright (erect) position are taken.
Presence of free air necessitates emergency laparotomy for perforated viscus.
chest x-ray:
may see free air under the diaphragm
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ABG:
may be normal; metabolic acidosis; elevated lactate
More
FBC:
elevated WBC count; may be normal in early obstruction
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Non-specific for diagnosis. Elevated WBC count indicates inflammation. Marked leukocytosis suggests advanced small bowel obstruction.[64]
Low haematocrit may indicate blood loss into the obstructed bowel. This is a potential sign of intestinal necrosis.
May indicate degree of volume depletion that is secondary to the obstruction.
serum electrolytes:
may not see any abnormalities with early obstruction; may confirm hypochloraemia and hypokalaemia; urea and creatinine may be elevated
More
CRP:
may be elevated
serum lipase or amylase:
normal
More
Performed to exclude acute pancreatitis. Serum lipase levels remain elevated for longer (up to 14 days after symptom onset vs. 5 days for amylase), providing a higher likelihood of picking up a diagnosis of pancreatitis in patients with a delayed presentation.[36]

Other investigations

water soluble contrast study:
may see dilated loops of proximal bowel with collapsed loops posterior to site of obstruction; absence of contrast in the colon
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Sensitivity 92% and specificity 93% for predicting resolution of obstruction without surgery.[65]
Radiographs should be performed 8 hours after administration of oral contrast.
pregnancy test:
negative
More

Incarcerated/strangulated hernia

History

history of hernia, intermittent, cramp-like abdominal pain; painful bulge; nausea, vomiting, decreased or absent bowel function; absence of flatus; distended abdomen

Exam

high-pitched (hyperactive) bowel sounds with rushes, or absent bowel sounds; distended abdomen, tenderness to abdominal palpation; tender bulge in abdominal wall or inguinal/femoral region; involuntary guarding; or indirect hernia (more common on right than left)

1st investigation

ABG:
may be normal; metabolic acidosis; elevated lactate
More
FBC:
may be normal in early obstruction; elevated WBC count as bowel infarction develops
More
serum electrolytes:
may be normal in early obstruction; may confirm hypochloraemia and hypokalaemia
More
CRP:
may be elevated
serum lipase or amylase:
normal
More
Performed to exclude acute pancreatitis. Serum lipase levels remain elevated for longer (up to 14 days after symptom onset vs. 5 days for amylase), providing a higher likelihood of picking up a diagnosis of pancreatitis in patients with a delayed presentation.[36]

Other investigations

CT of abdomen and pelvis:
may see dilated loops of proximal bowel with collapsed loops posterior to site of obstruction
More
Clinical examination is usually sufficient for the diagnosis of incarcerated/strangulated groin hernias. CT is used in selected cases to acquire additional diagnostic information.[30]
ultrasound of groin:
free fluid in hernia sac; bowel wall thickened; fluid within a herniated bowel loop; dilated intra-abdominal bowel loops
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Clinical examination is usually sufficient for the diagnosis of incarcerated/strangulated groin hernias. Ultrasound may be useful to confirm the diagnosis in obese patients or visualise the contents of the hernia sac preoperatively.[30]
pregnancy test:
negative
More

Inguinal hernia in adults

Cholecystitis

History

history of cholelithiasis and biliary colic; intense right upper quadrant pain, lasting more than 30 minutes, exacerbated by eating (especially fatty foods); right shoulder pain (referred pain from the gallbladder may be felt in the right shoulder or interscapular region); fever, nausea, and/or vomiting; more common in women than men; risk factors include obesity, age over 50, pregnancy, use of oestrogen, history of liver disease, cirrhosis, and pancreatitis

Exam

fever, tachycardia, right upper quadrant tenderness, Murphy's sign (right upper quadrant tenderness with arrest of inhalation during palpation), palpable gallbladder, local guarding, and jaundice

1st investigation

FBC:
elevated WBC count
More
LFTs:
may see elevated alkaline phosphatase, bilirubin, and aminotransferase
More
CRP:
>30 mg/L (>3 mg/dL)
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Elevated CRP is a risk factor for gallbladder perforation.[74]
right upper quadrant ultrasound:
gallstones; thickened gallbladder wall (>4 mm); pericholecystic fluid; may also see ultrasonographic Murphy's sign
More
Positive predictive value of >90%.[57][75][Figure caption and citation for the preceding image starts]: Cholecystitis: Operative photo showing acute cholecystitisFrom the collection of Dr Charles Bellows [Citation ends].[Figure caption and citation for the preceding image starts]: Cholecystitis: Ultrasound of acute cholecystitis and presence of gallstonesFrom the collection of Dr Charles Bellows [Citation ends].

Other investigations

cholescintigraphy (hepatobiliary iminodiacetic acid [HIDA] scan):
no contrast filling in gallbladder; may see patent cystic duct
More
pregnancy test:
negative
More
CT or MRI of abdomen and pelvis:
may show irregular thickening of the gallbladder wall, poor contrast enhancement of the gallbladder wall (interrupted rim sign), increased density of fatty tissue around the gallbladder, gas in the gallbladder lumen or wall, membranous structures within the lumen (intraluminal flap or intraluminal membrane), peri‐gallbladder abscess
More
In non-pregnant adults with suspected acute cholecystitis, if initial ultrasound is equivocal/non-diagnostic and clinical suspicion persists, an abdominal CT scan should be considered.[50] If both ultrasound and CT are equivocal/non-diagnostic and clinical suspicion persists, either an abdominal MRI/MRCP or cholescintigraphy (hepatobiliary iminodiacetic acid [HIDA] scan) should be considered.[50]

Acute cholecystitis

Perforated gastric ulcer

History

background of recurrent upper abdominal pain (dyspepsia); with nausea, vomiting, loss of appetite, and pain made worse by food; weight loss; use of non-steroidal anti-inflammatory drugs; sudden-onset severe upper abdominal pain with fever, nausea, vomiting, and peritoneal signs; referred pain to shoulders secondary to diaphragmatic irritation

Exam

often points to site of pain ('pointing sign'); develops into spreading upper abdominal pain; fever, peritoneal signs with guarding and rebound

1st investigation

ABG:
may be normal; metabolic acidosis; elevated lactate
More
blood cultures:
may detect bacteraemia
More
FBC:
microcytic anaemia; elevated WBC count
More
serum electrolytes:
may show elevated creatinine and urea
More
CRP:
usually elevated
serum lipase or amylase:
normal
More
Performed to exclude acute pancreatitis. Serum lipase levels remain elevated for longer (up to 14 days after symptom onset vs. 5 days for amylase), providing a higher likelihood of picking up a diagnosis of pancreatitis in patients with a delayed presentation.[36]
CT of abdomen and pelvis:
pneumoperitoneum
More
plain abdominal x-rays:
abdominal free air on erect abdominal film
More
chest x-ray:
may see free air under the diaphragm
More
Helicobacter pylori testing:
positive result if H pyloripresent
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All patients with a perforated ulcer should be tested for H pylori.[78]
Urea breath test is preferred. Stool antigen test also has high sensitivity and specificity. Serological tests should be locally validated, because they may perform differently depending on the antigenic composition of local strains.[79]

Other investigations

upper gastrointestinal series with water-soluble contrast:
extravasation of contrast from stomach
oesophagogastroduodenoscopy with biopsy:
may show Helicobacter pylori on culture and/or malignancy on histology
More
fasting serum gastrin level:
hypergastrinaemia in Zollinger-Ellison syndrome
pregnancy test:
negative
More

Peptic ulcer disease

Appendicitis

History

sudden-onset, constant, severe abdominal pain often periumbilical with migration to right lower quadrant, usually worse on movement; nausea, vomiting, anorexia, fever, diarrhoea, more common in children and young adults; pain may improve after appendix rupture

Exam

fever, tachycardia, patient may be lying in right lateral decubitus position with hips flexed; no or decreased bowel sounds; pain commonly originates near the umbilicus or the epigastrium; right lower quadrant (McBurney's point) tenderness with rigid abdomen; guarding and rebound tenderness; Rovsing's sign (palpation of left lower quadrant elicits pain in the right lower quadrant), psoas sign (right lower quadrant pain with right thigh extension), pain reproduced by coughing or hopping

1st investigation

FBC:
elevated WBC count
More
WBC count >15.0 x 10⁹/L (>15,000 cells/microL) suggests perforation or alternative aetiology.
Increased polymorphonuclear leukocytes (>75%). High discriminatory power when combined with history.[80]
May see leukocytosis with neutrophilia.
Appendicitis is very unlikely if WBC count and CRP both normal.[81]
CRP:
elevated
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Appendicitis is very unlikely if WBC count and CRP both normal. CRP increases with severity of appendicitis.[81]
CT scan of abdomen and pelvis with intravenous contrast:
abnormal appendix (diameter >6 mm) identified or calcified appendicolith seen in association with peri-appendiceal inflammation
More
Sensitivity and specificity >90%.[46][49][Figure caption and citation for the preceding image starts]: Appendicitis: CT abdomen showing thickened appendixCourtesy of Nasim Ahmed, MBBS, FACS [Citation ends]. Use of enteral contrast may improve specificity.[43]
Preoperative abdominal CT is associated with lower negative appendicectomy rates.[42]

Other investigations

pregnancy test:
negative
More
right lower quadrant ultrasound:
non-compressible appendix of ≥7 mm in anteroposterior diameter appendicolith; interruption of the continuity of the echogenic submucosa; peri-appendiceal fluid or mass
More
Sensitivity of 85%, specificity of 90%.[82]
May be performed as the initial imaging test in pregnant women.[43]
Obesity may preclude a definitive diagnosis.
Rapid technique that avoids radiation exposure.
MRI abdomen:
findings may include diffuse or segmental enlargement of the pancreas with irregular contour and obliteration of the peri-pancreatic fat, necrosis, or pseudocysts
More
May be performed as the initial imaging test in pregnant women.[43]
May be performed in children or women of childbearing age. Paediatric MRI may require anaesthesia. Gadolinium contrast crosses the placenta and should not be used in pregnancy.

Acute appendicitis

Ectopic pregnancy

History

vaginal bleeding with severe, usually unilateral pelvic pain; amenorrhoea or painless vaginal bleeding; history of recent early pregnancy or missed last menstrual period; risk factors include history of ectopic pregnancy, tubal surgery, pelvic inflammatory disease, infertility treatment and pregnancy with an intrauterine device in situ

Exam

may have palpable adnexal mass with or without tenderness; rigid abdomen, guarding, and rebound tenderness with ruptured ectopic leading to haemoperitoneum, tachycardia, and hypotension; vaginal bleeding on speculum examination

1st investigation

human chorionic gonadotrophin (hCG):
positive
More
Although the threshold at which a viable intrauterine pregnancy may be seen on transvaginal ultrasound is variable, if the hCG is greater than 1500-2000 IU/L (1500-2000 mIU/mL), then generally, evidence of an intrauterine gestation may be observed.
Threshold value varies with institution.
If hCG stable and diagnosis is unclear, hCG is measured again within 48 hours in the absence of acute abdominal findings.
Failure of hCG levels to increase by at least 50% in 48 hours generally indicates an abnormal pregnancy. However, this test does not indicate whether the abnormal pregnancy is extrauterine or intrauterine.[83]
FBC:
possible anaemia
transabdominal or transvaginal pelvic ultrasound:
no intrauterine pregnancy detected; ectopic pregnancy visualised
More
Blood or pseudogestational sac in uterus can be differentiated from a true gestational sac by absence of the double decidual sign, yolk sac or fetal pole.[58][Figure caption and citation for the preceding image starts]: Ectopic pregnancy: Ultrasound image of ectopic pregnancy showing the donut signFrom the personal collection of Dr Melissa Fries, Washington Hospital Center; used with permission [Citation ends].[Figure caption and citation for the preceding image starts]: Ectopic pregnancy: Ultrasound image of ectopic pregnancyFrom the personal collection of Dr Melissa Fries, Washington Hospital Center; used with permission [Citation ends].[Figure caption and citation for the preceding image starts]: Ectopic pregnancy: Ultrasound image of ectopic pregnancyFrom the personal collection of Dr Melissa Fries, Washington Hospital Center; used with permission [Citation ends].
Absence of intrauterine pregnancy using transvaginal ultrasound when hCG is 1500-2000 IU/L (>1500-2000 mIU/mL) may indicate ectopic pregnancy.

Other investigations

diagnostic laparoscopy:
ectopic pregnancy or complex mass seen
More
Presence of acute abdominal findings warrants either culdocentesis or diagnostic laparoscopy to rule out ruptured ectopic pregnancy when diagnosis is unclear, regardless of hCG or ultrasound findings.[Figure caption and citation for the preceding image starts]: Ectopic pregnancy: Surgical extraction of ectopic pregnancyFrom the personal collection of Dr Melissa Fries, Washington Hospital Center; used with permission [Citation ends].[Figure caption and citation for the preceding image starts]: Ectopic pregnancy: Surgical extraction of ectopic pregnancyFrom the personal collection of Dr Melissa Fries, Washington Hospital Center; used with permission [Citation ends].[Figure caption and citation for the preceding image starts]: Ectopic pregnancy: Blood in the abdomenFrom the personal collection of Dr Melissa Fries, Washington Hospital Center; used with permission [Citation ends].[Figure caption and citation for the preceding image starts]: Ectopic pregnancy: Blood in cul de sacFrom the personal collection of Dr Melissa Fries, Washington Hospital Center; used with permission [Citation ends].

Ectopic pregnancy

Pelvic inflammatory disease

History

sexually active, young age at onset of sexual activity, unprotected sexual intercourse with multiple sexual partners; prior infection with chlamydia or gonorrhoea; history of pelvic inflammatory disease; use of intrauterine device; lower abdominal or pelvic pain of recent onset or relatively short duration that may have begun after intercourse; abnormal vaginal discharge; fever (non-specific, but suggestive)

Exam

abdominal tenderness; abnormal vaginal discharge; cervical motion tenderness and adnexal tenderness will be present; bimanual examination may reveal a tubo-ovarian abscess

1st investigation

FBC:
elevated WBC count
More
erythrocyte sedimentation rate/CRP:
elevated
More
wet mount of vaginal secretions:
polymorphonuclear cells present
More
Negative predictive value 94.5% and positive predictive value 17.1% for upper genital tract infection.[93]
nucleic acid amplification test or culture of vaginal secretions:
may confirm infection with Chlamydia trachomatis or Neisseria gonorrhoeae

Other investigations

ultrasound:
tubal wall thickness >5 mm, incomplete septae within the tube, fluid in the cul-de-sac, and a cog-wheel appearance on the cross-section of the tubal view; may see complex adnexal mass, which could be indicative of a tubo-ovarian abscess
More
Definitive test to confirm presence of a tubo-ovarian abscess.[94]
Sensitivity for tubo-ovarian abscess as high as 95%.[95]

Pelvic inflammatory disease

Acute pancreatitis

History

acute-onset, constant, severe mid-abdominal/epigastric pain that often radiates to the back; nausea, vomiting; anorexia; history of biliary colic, alcohol misuse, use of specific medicines (e.g., sulphonamides, tetracycline, oestrogens, corticosteroids), trauma, or surgery

Exam

varying degrees of abdominal tenderness, usually worse in the epigastric region; guarding, abdominal distension, and reduced or absent bowel sounds; ecchymoses in the skin of one or both flanks (Grey-Turner's sign) and/or the periumbilical area (Cullen's sign)

1st investigation

serum lipase or amylase:
elevated (3 times the upper limit of normal)
More
Use serum lipase testing in preference to serum amylase.[34][35] Serum lipase levels remain elevated for longer (up to 14 days after symptom onset vs. 5 days for amylase), providing a higher likelihood of picking up the diagnosis in patients with a delayed presentation.[36]
About one quarter of people with acute pancreatitis fail to be diagnosed as having acute pancreatitis with serum amylase and serum lipase tests.[36][37]
The patient should be admitted and treated as having acute pancreatitis, even if these tests are normal, if there is a suspicion of acute pancreatitis.[36]
About 1 in 10 patients without acute pancreatitis may be wrongly diagnosed as having acute pancreatitis with these tests.[36] [ ] It is important to consider other conditions that require urgent surgery, even if these tests are abnormal.[36]
The diagnostic performance of these tests decreases with time, and additional investigations should be performed if there is a suspicion of acute pancreatitis.[36]
FBC:
elevated WBC count
LFTs:
normal or elevated alanine aminotransferase (ALT)
More
ALT ≥3 times the upper limit of normal has a positive predictive value of 95% for gallstone pancreatitis.[96] In the absence of choledocholithiasis, LFTs are usually normal. A slight increase in alkaline phosphatase and bilirubin may be seen.
urea and creatinine:
normal or elevated
More
Increased risk of severe disease if elevated.[34]
serum glucose:
normal or elevated
More

Other investigations

serum calcium:
may be elevated
More
serum triglycerides:
may be elevated
More
abdominal ultrasound:
may see ascites, gallstones, dilated common bile duct, and enlarged pancreas
More
Abdominal imaging is not needed for diagnosis in most patients. However, once a diagnosis of acute pancreatitis has been made, transabdominal ultrasound is required to rule out gallstones as the aetiology.[34]
CT scan of abdomen with oral and intravenous contrast:
may show pancreatic inflammation, peri-pancreatic stranding, calcifications, or fluid collections; confirms or excludes gallstones
More
Abdominal imaging is not needed for diagnosis in most patients.
Necrosis generally takes around 5 days to develop, so an early CT scan cannot be used to assess disease severity.
American College of Gastroenterology guidelines recommend CT or MRI after 48-72 hours in patients who do not improve or whose symptoms worsen.[34] Other guidelines recommend a delay of 72-96 hours after symptom onset before contrast-enhanced CT or MRI to assess for necrosis.[97][98]
magnetic resonance cholangiopancreatography (MRCP):
findings may include stones, diffuse or segmental enlargement of the pancreas with irregular contour and obliteration of the peri-pancreatic fat, necrosis, or pseudocysts
More
American College of Gastroenterology guidelines recommend CT or MRI after 48-72 hours in patients who do not improve or whose symptoms worsen.[34] Other guidelines recommend a delay of 72-96 hours after symptom onset before contrast-enhanced CT or MRI to assess for necrosis.[97][98]
MRI employing MRCP has the advantage of not requiring intravenous contrast or radiation, although intravenous gadolinium enhances images compared with non-contrast MRI.
In addition, MRCP allows better visualisation of common bile duct stones and the pancreatic duct compared with CT. It can more readily distinguish solid from cystic in dealing with peri-pancreatic collections.[99]
Used when contrast-enhanced CT is contraindicated.
pregnancy test:
negative
More

Acute pancreatitis

Acute diverticulitis

History

persistent left lower quadrant pain; fever, anorexia, nausea, vomiting, and abdominal distension (with ileus), patient may have a known history of diverticulosis

Exam

fever; left lower quadrant tenderness; frank blood in stool; diffuse tenderness with peritoneal signs (guarding, rebound tenderness, rigid abdomen) with perforation or ruptured abscess

1st investigation

FBC:
elevated WBC count
CT abdomen/pelvis with intravenous, oral, and rectal contrast:
may see diverticula, inflammation of pericolonic fat, thickening of the bowel wall, free abdominal air, and an abscess
More
Sensitivity of 69% to 95% and specificity of 75% to 100%.[47][100] The imaging modality of choice to confirm suspicion of acute diverticulitis or complicated diverticular disease.[44][47][48][50]

Other investigations

water-soluble contrast enema:
may see diverticula along with extravasation of contrast material into an abscess cavity or into the peritoneum
More
Use of barium enema should be avoided due to risk of barium peritonitis.
Sensitivity of 82% to 92%.[101][102] This test has largely been replaced by CT.
abdominal ultrasound:
may see fluid collections around the colon or a thickened hypoechoic bowel wall
More
Should be considered if CT scan cannot be obtained. Sensitivity of 84% to 98% and specificity of 80% to 93%.[103][104]
endoscopy:
may see inflamed diverticulum, abscess and perforation
More
laparoscopy:
allows direct visualisation of bowel if diagnosis is unclear
pregnancy test:
negative
More

Diverticular disease

Ulcerative colitis

History

bloody mucous diarrhoea and/or frank blood; fever, abdominal pain, weight loss, and growth retardation; back and joint pain and stiffness

Exam

abdominal tenderness; fevers; skin rash; episcleritis; pallor; guaiac-positive stools or frank blood on rectal examination

1st investigation

FBC:
variable degree of anaemia, leukocytosis, or thrombocytosis
comprehensive metabolic panel (including LFTs):
hypokalaemic metabolic acidosis; elevated sodium and urea; elevated alkaline phosphatase, bilirubin, aspartate aminotransferase, and alanine aminotransferase; hypoalbuminaemia
CRP and erythrocyte sedimentation rate:
elevated
stool studies:
negative culture, Clostridium difficile toxins A and B negative; WBCs present; elevated faecal calprotectin
plain abdominal radiograph:
dilated loops with air-fluid level secondary to ileus; free air is consistent with perforation; in toxic megacolon, the transverse colon is dilated to ≥6 cm in diameter
colonoscopy/sigmoidoscopy:
rectal involvement, continuous uniform involvement, loss of vascular marking, diffuse erythema, mucosal granularity, fistulas (rarely seen), normal terminal ileum (or mild 'backwash' ileitis in pancolitis)
biopsies:
continuous distal disease, mucin depletion, basal plasmacytosis, diffuse mucosal atrophy, absence of granulomata, and anal sparing; only mucosal/submucosal involvement

Other investigations

double-contrast barium enema:
results range from a fine granular appearance of the bowel wall to diffuse ulceration, thumbprinting (due to mucosal oedema), and narrowing and shortening of the bowel, depending on the severity of the disease
serological markers: perinuclear antineutrophil cytoplasmic antibody (pANCA):
may be positive
More
Approximately 70% of patients with ulcerative colitis have positive pANCA.[105]
CT abdomen/pelvis with oral and intravenous contrast:
may show thickening, inflammation, abscess, fistulisation, obstruction of the bowel; biliary dilation suggests primary sclerosing cholangitis
More
radionuclide studies:
positive areas of inflammation
pregnancy test:
negative
More

Ulcerative colitis

Crohn's disease

History

family history of Crohn's disease; typical age range 15-40 or 60-80 years; fevers, abdominal pain, prolonged intermittent bloody or non-bloody diarrhoea; fatigue; anal discharge and abscess; weight loss; faltering growth in children

Exam

abdominal tenderness often periumbilical or right lower quadrant if terminal ileum inflamed, mimicking appendicitis; peri-anal disease with fissures, skin tags fistulae, sinuses, and abscesses; aphthous ulcers; blood on rectal examination

1st investigation

FBC:
anaemia; leukocytosis; may be thrombocytosis
comprehensive metabolic panel:
hypoalbuminaemia, hypocholesterolaemia, hypocalcaemia
CRP and erythrocyte sedimentation rate:
elevated
iron studies:
normal, or may demonstrate changes consistent with iron deficiency
More
serum vitamin B12:
may be normal or low
serum folate:
may be normal or low
stool testing:
absence of infectious elements seen on microscopy or culture; faecal calprotectin may be elevated
plain abdominal films:
small bowel or colonic dilation; calcification; sacroiliitis; intra-abdominal abscesses
CT abdomen:
skip lesions, bowel wall thickening, surrounding inflammation, abscess, fistulae
More
Helps in localisation of the disease and diagnosing fistulae, abscesses, and other extramural complications.[Figure caption and citation for the preceding image starts]: Crohn's disease: CT scan demonstrating thickening of the terminal ileum in a patient with Crohn's disease exacerbationProvided by Drs Wissam Bleibel, Bishal Mainali, Chandrashekhar Thukral, and Mark A. Peppercorn [Citation ends].[Figure caption and citation for the preceding image starts]: Crohn's disease: CT scan demonstrating thickening of the terminal ileum in a patient with Crohn's disease exacerbationProvided by Drs Wissam Bleibel, Bishal Mainali, Chandrashekhar Thukral, and Mark A. Peppercorn [Citation ends].
Yersinia enterocolitica serology:
negative
More

Other investigations

MRI abdomen/pelvis:
skip lesions, bowel wall thickening, surrounding inflammation, abscess, fistulae
More
Superior to CT scanning in demonstrating pelvic lesions. MRI has high diagnostic accuracy for small bowel disease.[106]
abdominal and pelvic ultrasonography:
bowel wall thickening, surrounding inflammation, abscess; tubo-ovarian abscess
colonoscopy:
aphthous ulcers, hyperaemia, oedema, cobblestoning, skip lesions
More
Enables direct visualisation and biopsy.[Figure caption and citation for the preceding image starts]: Crohn's disease: Endoscopic view of Crohn's ileitisProvided by Drs Wissam Bleibel, Bishal Mainali, Chandrashekhar Thukral, and Mark A. Peppercorn [Citation ends].[Figure caption and citation for the preceding image starts]: Crohn's disease: Endoscopic view of normal terminal ileumFrom the personal collection of Dr Charlotte Ford, North Middlesex Hospital Trust, London, UK [Citation ends].
tissue biopsy:
mucosal bowel biopsies demonstrate transmural involvement with non-caseating granulomas
technetium-99 labelled WBC scanning:
increased uptake in the inflamed segments
More
oesophagogastroduodenoscopy:
aphthous ulcers; mucosal inflammation
wireless capsule endoscopy:
aphthous ulcers; hyperaemia; oedema; cobblestoning; skip lesions
More
anti-glycan antibodies:
positive anti-Saccharomyces cerevisiae mannan antibodies (ASCA) and negative perinuclear neutrophil cytoplasmic antibodies
More
Anti-glycan antibodies (e.g., anti-Saccharomyces cerevisiae [ASCA], anti-laminaribiose [ALCA], anti-chitobioside [ACCA], anti-laminarin [anti-L], anti-chitin [anti-C]) and antibodies to microbial antigens (anti-outer membrane porin C [anti-OmpC], anti-Cbir1 flagellin, anti-I2, and p-ANCA) are more prevalent in Crohn's disease than in ulcerative colitis, but have a low sensitivity.[107] Routine use of serological markers of inflammatory bowel disease to establish the diagnosis of CD is not recommended.[107] However, ASCA may be of prognostic value in children with CD.[108][109]
pregnancy test:
negative
More

Crohn's disease

Cholelithiasis

History

right upper quadrant or epigastric pain (lasting more than 30 minutes) sometimes associated with food

Exam

right upper quadrant or epigastric tenderness; jaundice

1st investigation

LFTs:
may be normal or elevated alkaline phosphatase and elevated bilirubin
abdominal ultrasound:
demonstrates stones in the gallbladder
More
For biliary pain. This is the best single test (sensitivity 89.8% and specificity 88.0% for emergency physician use) for cholelithiasis and sludge in the gallbladder, a key to diagnosis.[110]
For bile duct dilation. Low sensitivity for choledocholithiasis. If stones are detected in the gallbladder with pericholecystic fluid and gallbladder wall thickening, consider acute cholecystitis.[110][Figure caption and citation for the preceding image starts]: Ultrasound of acute cholecystitis and presence of gallstones: the arrow points to a gallstone in the fundus of the gallbladder with its echogenic shadow belowCourtesy of Charles Bellows and W. Scott Helton; used with permission [Citation ends].[Figure caption and citation for the preceding image starts]: Gallbladder ultrasound demonstrating cholelithiasis with characteristic shadowingCourtesy of Kuojen Tsao; used with permission [Citation ends].
Endoscopic ultrasound is more sensitive for microlithiasis (small gallstones <3 mm).
serum lipase and amylase:
elevated (>3 times upper limit of normal) in acute pancreatitis
More

Other investigations

endoscopic retrograde cholangiopancreatography (ERCP):
ERCP demonstrates stones in the gallbladder or bile duct
More
ERCP is recommended in patients with a high risk of choledocholithiasis (i.e., common bile duct stone seen on ultrasound/cross-sectional imaging; OR total bilirubin >4 mg/dL and dilated common bile duct; OR ascending cholangitis).[111]
magnetic resonance cholangiopancreatography (MRCP):
MRCP demonstrates stones in the gallbladder or bile duct
More
MRCP is recommended in patients with an intermediate risk of choledocholithiasis (i.e., abnormal LFTs; OR age >55 years; OR dilated common bile duct on ultrasound/cross-sectional imaging).[111]
endoscopic ultrasound (EUS):
stones in gallbladder or bile duct
More
EUS is recommended for patients with an intermediate risk of choledocholithiasis (i.e., abnormal LFTs; OR age >55 years; OR dilated common bile duct on ultrasound/cross-sectional imaging).[111]
pregnancy test:
negative
More

Cholelithiasis

Gastrointestinal malignancy

History

nausea, vomiting, abdominal pain and distension (especially with distal obstruction); little or no flatus or bowel function; weight loss; black stools

Exam

may have palpable mass, pallor, or cachexia; if obstruction present, distended abdomen, high-pitched (hyperactive) bowel sounds with rushes, or absent bowel sounds; tenderness to abdominal palpation, involuntary guarding; tachycardia

1st investigation

FBC:
variable level of anaemia
quantitative faecal immunochemical testing:
positive
More
Guaiac can react with food or medicine leading to a false-positive result, but quantitative faecal immunochemical tests (FITs) use antibodies specific to the globin part of human haemoglobin to detect small amounts of blood.[40][112] As globin degrades while traversing the gastrointestinal tract, theoretically these tests are less likely to detect globin from upper gastrointestinal bleeding.[112]
The US and UK guidelines report risk thresholds for testing symptomatic patients.[38][39][40] The UK’s National Institute for Health and Care Excellence (NICE) recommends certain FIT for the recognition and referral of patients at risk of colorectal cancer.[39][40] Adults with a FIT result of at least 10 micrograms of haemoglobin per gram of faeces should be referred using a suspected cancer pathway referral for colorectal cancer (for a diagnosis or ruling out of cancer within 28 days of being referred urgently).[39][40]
renal function:
normal, except if advanced pelvic disease is compressing ureters
LFTs:
normal, except if liver metastases present
chest x-ray:
normal or evidence of metastatic disease
oesophagogastroduodenoscopy with biopsy:
may show upper gastrointestinal ulcer, mass, or mucosal changes and provide histological confirmation
colonoscopy with biopsy:
ulcerating exophytic mucosal lesion that may narrow the bowel lumen; histological confirmation
CT thorax/abdomen/pelvis with oral and intravenous contrast:
hypodense lesions around tumour site or at distant metastatic sites (e.g. liver); colonic wall thickening, enlarged lymph nodes, liver metastases, ascites, lung secondaries; invasion of mesorectal fascia
CT colonography:
appearances similar to conventional colonoscopy, with an ulcerating exophytic mucosal lesion that may narrow the bowel lumen

Other investigations

upper gastrointestinal endoscopic ultrasound:
determines clinical tumour (T) and node (N) stage of upper gastrointestinal tumours
transrectal endoscopic ultrasound:
determines clinical tumour (T) and node (N) stage of rectal tumours
carcinoembryonic antigen:
elevated in colorectal cancer
pregnancy test:
negative
More

Mallory-Weiss tear

History

vomiting or coughing with subsequent haematemesis; retrosternal, epigastric, or back pain; melena; presyncope/syncope; dysphagia, odynophagia

Exam

postural/orthostatic hypotension; pallor, tachycardia

1st investigation

erect chest x-ray:
may show free air
oesophagogastroduodenoscopy:
bleeding, adherent clot, or fibrous rind over an area of mucosal split at or near the gastro-oesophageal junction
More
Enables direct visualisation and therapeutic intervention.[Figure caption and citation for the preceding image starts]: Mallory-Weiss tear: Actively bleeding tear appears as a red longitudinal defect with normal surrounding mucosaFrom the collection of Juan Carlos Munoz, MD, University of Florida [Citation ends].[Figure caption and citation for the preceding image starts]: Mallory-Weiss tear: Non-bleeding adherent clotFrom the collection of Juan Carlos Munoz, University of Florida [Citation ends].

Other investigations

Mallory-Weiss tear

Diabetic ketoacidosis

History

inadequate or inappropriate insulin therapy, infection (pneumonia and urinary tract infections are the most common), myocardial infarction; anorexia, nausea, vomiting, polyuria, thirst; abdominal pain; fever; dizziness, weakness, mental status change

Exam

acetone breath; deep, laboured, gasping breathing (Kussmaul's breathing); signs of hypovolaemia (tachycardia, hypotension, poor capillary refill, sunken eyes); abdominal tenderness; altered mental status

1st investigation

plasma glucose:
elevated
serum electrolytes and urea:
usually sodium low, potassium elevated, chloride low, magnesium low, calcium low, phosphate normal or elevated, urea elevated, creatinine elevated
arterial blood gases:
pH varies from 7.00 to 7.30 in diabetic ketoacidosis (DKA); arterial bicarbonate ranges from <10 mmol/L (<10 mEq/L) in severe DKA to >15 mmol/L (>15 mEq/L) in mild DKA
urinalysis:
positive for glucose and ketones; positive for leukocytes and nitrites in the presence of infection
serum ketones:
elevated
FBC:
elevated WBC count
More

Other investigations

Diabetic ketoacidosis

Opioid withdrawal

History

history of drug use/misuse; fever, chills, nausea, vomiting; crampy abdominal pain; change of bowel habit; sweating, tremors, confusion, agitation, anxiety, muscular aches, increased salivation, dilated pupils

Exam

diffuse abdominal pain and tenderness; abdomen usually not distended; dilated pupils, confusion, sweating, copious salivation

1st investigation

urine drug screen:
positive
More
gas chromatography-mass spectroscopy:
positive
More
A positive urine screen should be followed by a confirmatory urine test, because certain medications (e.g., antibiotics) can interfere with the screen and produce false-positive results.[123][124]

Other investigations

CT abdomen/pelvis:
may indicate intra-abdominal source
pregnancy test:
negative
More

Opioid use disorder

Gastroenteritis

History

nausea, vomiting, diarrhoea, crampy abdominal pain; history of sick contacts with similar symptoms; ingestion of questionable food or water; recent travel to places with insanitary conditions

Exam

dehydration; tachycardia; soft, non-distended abdomen; diffuse abdominal tenderness

1st investigation

FBC:
elevated WBC count
serum electrolytes and urea:
variable, may show dehydration
stool for culture, ova and parasites:
may identify infectious agent
More

Other investigations

stool leukocytes:
positive
CT abdomen/pelvis with oral and intravenous contrast:
may show non-specific thickening of affected bowel
More
pregnancy test:
negative
More

Infectious colitis

History

fever, chills, nausea, vomiting, diarrhoea (may be bloody), abdominal pain; abdominal distention, malaise, and anorexia; may have been recent travel, community outbreak or close contact with people with similar symptoms, recent use of antibiotics or hospitalisation; immunocompromise

Exam

pyrexia, abdominal pain and tenderness; variable signs from mild dehydration to hypovolaemic shock/septic shock (hypotension, tachycardia); peritonitis; possible abdominal distention

1st investigation

FBC:
elevated WBC count and/or anaemia
serum electrolytes and urea:
variable, may show dehydration
stool culture:
may identify infectious agent

Other investigations

stool immunoassay for Clostridioides difficile toxins A and B:
may be positive
More
stool culture for ova/parasites:
may be positive
More
cytomegalovirus antigen/shell assay:
may be positive
More
abdominal x-ray:
may show distended colon
CT abdomen/pelvis with contrast:
may show thickened and inflamed segments of colon or all of colon affected; may show pneumatosis or localised perforation or perforation with phlegmon/abscess in severe cases
More
Image:[Figure caption and citation for the preceding image starts]: Clostridium difficile-associated disease: CT scan of the abdomen showing gross thickening of the large bowel wall and obliteration of the lumenYates B, Murphy CM, et al. Pseudomembranous colitis in four patients with cystic fibrosis following lung transplantation. BMJ Case Reports. 2009; doi: 10.1136/bcr.11.2008.1218 [Citation ends].
pregnancy test:
negative
More

Sickle cell crisis

History

history of sickle cell anaemia; diffuse bodily pain which can include abdominal pain, bone pain, chest pain; may also have fatigue, fever, jaundice, tachycardia, delayed growth and puberty; skin ulcers

Exam

diffuse acute abdominal pain and tenderness on palpation; patient is uncomfortable in any position; abdomen is usually not distended; fever

1st investigation

FBC with reticulocyte count:
some degree of anaemia occurs in most patients with sickle cell disease; leukocytosis common in acute pain crises
peripheral blood smear:
presence of nucleated red blood cells, sickle-shaped cells, and Howell-Jolly bodies
urea and creatinine:
normal or elevated
More
LFTs:
variable
More
bacterial cultures:
pathogen detected
More
abdominal ultrasound:
may show enlarged spleen or presence of gallstones; hepatomegaly
More
CT abdomen/pelvis:
may show enlarged spleen or presence of gallstones; hepatic or renal infarction
More

Other investigations

haemoglobinopathy testing:
sickle cell haemoglobin mutation
More
chest x-ray:
presence of pulmonary infiltrate(s) may be an indication of acute chest syndrome
More
pregnancy test:
negative
More

Sickle cell anaemia

Endometriosis

History

dysmenorrhoea; cyclical lower abdominal/pelvic/back pain, often 1-2 weeks before menstruation and during menstruation; pain during bowel movements; dyspareunia; sub-fertility; urinary or bowel obstruction; depression

Exam

discomfort and uterosacral ligament nodularity during bimanual/rectovaginal examination; tenderness on palpation in lower abdomen; fixed retroverted uterus in late stages; pelvic mass (ovarian endometriomas)

1st investigation

transvaginal ultrasound:
may show ovarian endometrioma (homogeneous, low-level echoes) or evidence of deep pelvic endometriosis such as uterosacral ligament involvement (hypoechoic linear thickening)
More

Other investigations

diagnostic laparoscopy:
direct visualisation of endometrial implants and histological confirmation of biopsies
More
Images:[Figure caption and citation for the preceding image starts]: Endometriosis: Laparoscopic image of endometriotic noduleFrom the collection of Dr Jonathon Solnik; used with permission [Citation ends].[Figure caption and citation for the preceding image starts]: Endometriosis: Laparoscopic image of ovarian endometriomaFrom the collection of Dr Jonathon Solnik; used with permission [Citation ends].
rectal endoscopic ultrasound:
hypoechoic nodule or mass
More
MRI pelvis:
hypointense, irregular thickening or mass of uterosacral ligament; replacement of fat tissue plane between uterus and rectum/sigmoid with tissue mass
More
Useful for imaging the entire abdomen and pelvis. Ovarian disease can be easily seen.
Sensitivity and specificity for deep pelvic disease is approximately 90%, but is consistently lower for uterosacral ligament and higher for gastrointestinal disease.[126]
pregnancy test:
negative
More

Endometriosis

Testicular torsion

History

history of previous on-off testicular pain; sudden-onset testicular pain with nausea and vomiting; scrotal oedema/swelling/erythema; abdominal pain also often present

Exam

severe testicular pain and tenderness on affected side; may be swollen; affected testicle is located higher than the non-affected testicle, often in horizontal position; reduced or absent cremasteric reflex

1st investigation

surgical exploration of the scrotum:
testicular torsion
More
grey-scale ultrasound:
presence of fluid and the whirlpool sign (the swirling appearance of the spermatic cord from torsion as the ultrasound probe scans downwards perpendicular to the spermatic cord)
FBC:
normal
More

Other investigations

power Doppler ultrasound:
absent or decreased blood flow in the affected testicle; decreased flow velocity in the intratesticular arteries, increased resistive indices in the intratesticular arteries
colour Doppler ultrasound:
absent or decreased blood flow in the affected testicle; decreased flow velocity in the intratesticular arteries, increased resistive indices in the intratesticular arteries
More
Image:[Figure caption and citation for the preceding image starts]: Testicular torsion: Bilateral transverse color Doppler images in a 12-year-old boy with right-sided scrotal pain of sudden onset, showing no colour flow signals in the right testis, which is enlarged and has heterogeneous echogenicity; reactive hydrocele (h) and thickening of the scrotal wall (*) are also seen; testicular torsion and bell clapper deformity were confirmed at surgeryAso C, et al. Radiographics. 2005 Sep-Oct;25(5):1197-214; used with permission [Citation ends].
spectral Doppler:
non-homogeneous and/or asymmetric vascular perfusion compared with the unaffected testis
scintigraphy:
decreased uptake of radioactive technetium-99m to the affected testicle in patients with testicular torsion
More
Scintigraphy has almost 100% sensitivity for identifying patients with torsion.[127] However, scintigraphy takes longer and is less readily available than Doppler ultrasound.

Testicular torsion

Kidney stones

History

previous history of kidney stones; may be asymptomatic to severe abdominal flank pain radiating to the groin; other symptoms include nausea, vomiting, diaphoresis, haematuria; urinary frequency/urgency; occupations in hot conditions (e.g., chefs, steel workers); family history of stones

Exam

often obese; abdomen soft; when in pain, may be severe, unable to find comfortable position; tender to palpation/percussion of costovertebral angle/flank; if urosepsis also present may be tachycardic, hypotensive, pyrexial

1st investigation

urinalysis:
dipstick positive for leukocytes, nitrates, blood; microscopic analysis positive for WBCs, red blood cells, or bacteria; may be normal
More
Microhaematuria is seen in approximately 10% to 20% of patients with renal stones.[128]
FBC:
normal or raised WBC count
More
serum electrolytes, urea, and creatinine:
normal or deranged
More
uric acid level:
normal or elevated
More
non-contrast helical CT abdomen/pelvis (stone protocol):
calcification seen in renal collecting system or ureter

Other investigations

renal ultrasound:
calcification seen within urinary tract
retrograde urethrogram:
calcification seen within urinary tract or a filling defect seen
intravenous pyelogram:
calcification seen within urinary tract or a filling defect seen when dye is passing through the kidney and down the ureter
More
pregnancy test:
negative
More

Nephrolithiasis

Pyelonephritis

History

family history of kidney stones; history of urinary tract infection, stress incontinence, or frequent sexual intercourse; fever with chills; dysuria, frequency, urgency; flank pain; nausea, vomiting, diaphoresis, haematuria

Exam

pyrexia; flushed looking; flank pain and/or costovertebral angle tenderness on palpation/percussion

1st investigation

urinalysis:
pyuria (>10 WBCs per high-power field [HPF]), red blood cells ≥5/HPF, leukocyte esterase, nitrites, WBC casts, proteinuria up to 20 g/L (2 g/dL)
Gram stain:
typically gram-negative rods; less typically gram-positive cocci
urine culture:
positive
FBC:
leukocytosis
CRP:
elevated
More

Other investigations

blood cultures:
may be positive
More
CT abdomen/pelvis with intravenous contrast:
altered renal parenchymal perfusion; altered excretion of contrast; perinephric fluid; non-renal disease; may show abscess formation
More
renal ultrasound:
gross structural abnormalities; hydronephrosis; stones; perirenal fluid collections
More
99mTc-dimercaptosuccinic acid scintigraphy:
inflammation or scarring of the renal cortex; unequal distribution of renal function between the kidneys
More
MRI:
structural anomalies of the genitourinary system (prenatal); renal inflammation or masses; abnormal renal vasculature; urinary obstruction
More
pregnancy test:
negative
More

Acute pyelonephritis

Uncommon

Volvulus

History

steady abdominal pain that may have colicky characteristics varying from vague discomfort to excruciating (severe unremitting pain suggests gangrenous bowel); history of abdominal surgery, abdominal or inguinal hernia; nausea, vomiting, emesis may be absent in patients with sigmoid volvulus (more common in older or debilitated patients); periumbilical or hypogastric pain, diarrhoea or constipation (depending on the degree and location of the obstruction)

Exam

often diffuse abdominal distension and tenderness; faint or no bowel sounds, rigid abdomen, guarding, rebound tenderness, fever, or haematochezia

1st investigation

plain abdominal x-rays:
partial or complete obstruction; dilated bowel loops; air-fluid levels; abdominal free air with perforation
More
ABG:
may be normal; metabolic acidosis; elevated lactate
More
chest x-ray:
may see free air under the diaphragm
More
FBC:
elevated WBC count
More
serum electrolytes:
may be normal in early obstruction; may confirm hypochloraemia and hypokalaemia; urea and creatinine may be elevated
More
CRP:
may be elevated

Other investigations

barium or water-soluble contrast enema:
bird's-beak sign of stricture at the site of the volvulus
More
CT of abdomen:
bowel obstruction with whirl pattern of mesentery[67]
More

Retroperitoneal haemorrhage

History

symptoms may be vague; groin, lower abdominal or back pain; history of risk factors (e.g., recent anticoagulation use, recent history of transfemoral catheterisation, recent obstetric procedure in women of childbearing age, malignancy, pelvic or spine fractures)

Exam

non-specific findings including unexplained tachycardia; diffuse abdominal, back, or lower quadrant abdominal pain, abdominal distension; may be bruising of flank; flank mass on palpation; diaphoresis if severe; profound hypotension with decreasing levels of consciousness if shock present

1st investigation

basic test panel (FBC, serum electrolytes, blood glucose, serum LFTs, coagulation profile, group and save):
low Hb; INR may be raised
ECG:
normal, or tachycardia
CT abdomen and pelvis:
haematoma may be visualised
More
The American College of Radiology recommend that either CT of the abdomen and pelvis with IV contrast, CT of the abdomen and pelvis without and with IV contrast, or CTA of the abdomen and pelvis with IV contrast are usually appropriate for the initial imaging of clinically suspected retroperitoneal bleed in a patient.[68]
abdominal and pelvic CT angiography:
may demonstrate active bleeding site if bleeding is ongoing
More
The American College of Radiology recommend that either CT of the abdomen and pelvis with IV contrast, CT of the abdomen and pelvis without and with IV contrast, or CTA of the abdomen and pelvis with IV contrast are usually appropriate for the initial imaging of clinically suspected retroperitoneal bleed in a patient.[68]

Other investigations

Viral Hepatitis

History

perinatal exposure, family history of hepatitis B viral infection, blood transfusions, high-risk activities (e.g., multiple sexual partners, men who have sex with men, injection drug users, intravenous drug use); right upper quadrant pain; fever, chills, fatigue, myalgia/arthralgia; nausea, vomiting; jaundice

Exam

right upper quadrant tenderness; hepatosplenomegaly; jaundice; ascites; maculopapular or urticarial rash

1st investigation

FBC:
elevated; non-specific
LFTs:
elevated transaminases (alanine aminotransferase/aspartate aminotransferase), alkaline phosphatase, and bilirubin
serum electrolytes, urea, and creatinine:
usually normal
More
hepatitis serology and antigens:
positive
More

Other investigations

ultrasound right upper quadrant:
poorly defined margins and coarse, irregular internal echoes in hepatitis B
prothrombin time:
prolonged
More
pregnancy test:
negative
More

Hepatitis B

Intussusception

History

more common in children than in adults; classic presentation of severe, colicky pain alternating with lethargy; may also present with vague abdominal complaints; severe, cramp-like abdominal pain; children may be inconsolable; vomiting

Exam

occult or frank blood mixed with mucus giving currant-jelly appearance, abdominal tenderness, and palpable mass

1st investigation

ultrasound:
tubular mass in longitudinal view; target lesion in transverse view
More
Sensitivity 98% to 100%. Specificity 88% to 100%. Negative predictive value 100%.[69][70]
The mass resulting from intussusception may be easily identified; the findings of intussusception by ultrasound closely mirror its pathophysiological process.[Figure caption and citation for the preceding image starts]: Intussusception: Ultrasound image showing invagination of a segment of bowel into the adjacent segmentBMJ Case Reports 2009; doi:10.1136/bcr.04.2009.1730 [Citation ends].[Figure caption and citation for the preceding image starts]: Intussusception: Transverse sonogram of the abdomen showing the donut sign (concentric rings within the lumen of a distended loop of bowel)Adapted from the Student BMJ. 2008;16:76 [Citation ends].
Can be used to monitor success of treatment with enema.
air or water enema:
filling defect or cupping in the head of contrast as it advances to the site of the intussusception
More
Air or hydrostatic enema can be used to reduce intussusception in 60% to 80% of childhood cases.[71]
Preferred initial test for children.
Contraindicated if peritonitis, shock, perforation, or an unstable clinical condition is present.[72][Figure caption and citation for the preceding image starts]: Intussusception: Abdominal x-ray showing impaired passage of barium at site of obstruction due to intussusceptionFrom the collection of Dr David J. Hackam [Citation ends].[Figure caption and citation for the preceding image starts]: Intussusception: Site of intussusception as revealed by abdominal x-ray, showing the meniscusFrom the collection of Dr David J. Hackam [Citation ends].[Figure caption and citation for the preceding image starts]: Intussusception: Site of intussusception as revealed by abdominal x-ray, showing the meniscusFrom the collection of Dr David J. Hackam [Citation ends].
FBC:
elevated WBC count
More
serum electrolytes:
may be normal in early obstruction; may confirm hypochloraemia and hypokalaemia; urea and creatinine may be elevated
More
CRP:
may be elevated

Other investigations

CT of abdomen and pelvis:
target lesion: intraluminal soft-tissue density mass with an eccentrically placed fatty area; reniform mass: high attenuation peripherally and lower attenuation centrally; sausage-shaped mass: alternating areas of low and high attenuation representing closely spaced bowel wall, mesenteric fat, and/or intestinal fluid and gas
More

Intussusception

Perforated duodenal ulcer

History

acute onset of severe epigastric pain, nausea, vomiting, and loss of appetite; more common in men than women; history of melaena or bright red blood from rectum, episodic epigastric pain relieved by eating; use of non-steroidal anti-inflammatory drugs; may have latent period with symptom improvement that may last several hours, followed by peritonitis with fever, nausea, vomiting, and peritoneal signs; referred pain to shoulders secondary to diaphragmatic irritation

Exam

tachycardia, fever, epigastric tenderness, rigid abdomen, guarding, rebound tenderness, and occult or frank blood in stool

1st investigation

ABG:
may be normal; metabolic acidosis; elevated lactate
More
blood cultures:
may detect bacteraemia
More
FBC:
elevated WBC count
More
serum electrolytes:
may show elevated creatinine and urea
More
CRP:
usually elevated
serum lipase or amylase:
normal
More
Performed to exclude acute pancreatitis. Serum lipase levels remain elevated for longer (up to 14 days after symptom onset vs. 5 days for amylase), providing a higher likelihood of picking up a diagnosis of pancreatitis in patients with a delayed presentation.[36]
CT of abdomen and pelvis:
pneumoperitoneum
More
plain abdominal x-rays:
abdominal free air on erect abdominal film
More
chest x-ray:
may see free air under the diaphragm
More
Helicobacter pylori testing:
positive result if H pylori present
More
All patients with a perforated ulcer should be tested for H pylori.[78]
Urea breath test is preferred. Stool antigen test also has high sensitivity and specificity. Serological tests should be locally validated, because they may perform differently depending on the antigenic composition of local strains.[79]

Other investigations

upper gastrointestinal series with water-soluble contrast:
extravasation of contrast from stomach or duodenum
esophagogastroduodenoscopy with biopsy:
visualisation of ulcer; histological confirmation

Peptic ulcer disease

Ruptured ovarian cyst

History

often days 20 and 26 of a normal menstrual cycle; often follows intercourse, exercise, or pelvic examination; sudden-onset lower abdominal pain, may be lateralised to left or right; light vaginal bleeding; postural dizziness if marked haemorrhage (associated with rupture of corpus luteum cyst, specifically among patients on anticoagulants or with bleeding disorders)

Exam

light vaginal bleeding; vital signs usually normal, but may be low-grade fever; may have tachycardia/hypotension if severe bleeding in association with coagulopathy or anticoagulant use; signs of peritonitis if haemoperitoneum present

1st investigation

transvaginal ultrasound:
enlarged ovary or portion of ovarian tissue; may be cystic, solid, or mixed; free pelvic fluid
More
pregnancy test:
positive or negative
More

Other investigations

Ovarian cysts

Ovarian torsion

History

sudden onset of unilateral pain, waxing and waning severe pelvic pain, and history of adnexal mass

Exam

severe, unilateral adnexal tenderness; adnexal mass that is often palpable and, in advanced cases, patient may develop rigid abdomen, guarding, and rebound tenderness

1st investigation

pregnancy test:
negative
More
pelvic ultrasound with Doppler study:
no Doppler flow to affected ovary
More

Other investigations

Ovarian torsion

Abdominal aortic dissection

History

severe, sharp, or tearing pain in thorax or abdomen, pain radiates to neck or back, history of hypertension, increased risk in Marfan's syndrome and Ehlers-Danlos syndrome or other collagen vascular disorders, painless dissection is rare

Exam

hypertension in distal dissection; lower extremity pulse deficit, sensory or motor deficits (including numbness, tingling, or transient paraplegia); ischaemia and, if mesenteric arteries involved, bowel ischaemia with rigid abdomen, guarding and rebound tenderness

1st investigation

serum urea and electrolytes:
elevated urea
More
plain abdominal x-rays:
aortic wall calcification consistent with abdominal aortic aneurysm; loss of psoas shadow in presence of rupture
More
CT angiography of chest and abdomen:
two aortic lumina separated by intimal flap or displaying different rates of contrast opacification
magnetic resonance angiography of chest and abdomen:
two aortic lumina separated by intimal flap; branch vessel involvement; aortic regurgitation
More
chest x-ray:
widened aortic silhouette; widened mediastinum
More

Other investigations

contrast aortography:
two aortic lumina separated by intimal flap; branch vessel involvement; aortic regurgitation
More

Ruptured aortic aneurysm

History

severe abdominal pain radiating to back, flank, groin, or legs; patient unaffected by position; history of aneurysm, possible discoloration and pain in lower extremities due to ischaemia

Exam

tachycardia, hypotension, pulsatile abdominal mass, nausea, vomiting, lower extremity pulse deficit, lower extremity or back pain, loss of consciousness or confusion, limb numbness or tingling, ischaemia and livedo reticularis

1st investigation

abdominal ultrasound:
aortic aneurysm
More

Other investigations

CT of chest and abdomen with intravenous contrast:
aortic aneurysm, extravasation of contrast
More

Abdominal aorta aneurysm

Acute mesenteric ischaemia (AMI) and infarction

History

age >50 years; constant periumbilical non-radiating abdominal pain; recent history of post-prandial abdominal pain; history of atrial fibrillation, coronary artery disease, myocardial infarction, and congestive heart failure; melaena or bright red blood from rectum, and patient taking vaso-active medicines; risk factors include smoking, hypertension, hyperlipidaemia, and diabetes

Exam

initially, pain out of proportion to examination findings with soft, non-tender abdomen despite severe abdominal pain, followed by rigid abdomen, guarding, and rebound tenderness with bowel necrosis and perforation, and, in advanced cases, fever, tachycardia, and hypotension will be present

1st investigation

CT of abdomen:
vessel thrombosis; thickened bowel wall; abnormal bowel wall enhancement; pneumatosis; portal or mesenteric venous gas
More
If the use of contrast material is possible, biphasic contrast material-enhanced multi-detector CT is the imaging test of choice for early diagnosis of the disease and for differentiation from other causes of acute abdomen.
The diagnostic performance for detection of AMI using multi-detector CT is reported to be high, with a sensitivity of 64%-96% and a specificity of 92%-100%.[88][89]
If abnormal, proceed to angiography or laparotomy.[Figure caption and citation for the preceding image starts]: Ischaemic bowel disease: CT scan showing colonic thickening with pneumatosis intestinalisFrom the collection of Dr Jennifer Holder-Murray and Dr Alessandro Fichera [Citation ends].[Figure caption and citation for the preceding image starts]: Ischaemic bowel disease: CT angiogram: acute superior mesenteric artery thrombusFrom the collection of Dr Jennifer Holder-Murray and Dr Alessandro Fichera [Citation ends].[Figure caption and citation for the preceding image starts]: Ischaemic bowel disease: 84-year-old man presenting with symptoms suggestive of ischaemic bowel disease: (A) Abdominal CT revealing a massive circumferential and band-like air formation as intestinal pneumatosis (arrows) and pronounced edema of mesenteric fat (arrowhead) around necrotic bowel loops; (B) Another slice of abdominal CT showing long segmental pneumatosis of the small bowelLin I, Chang W, Shih S, et al. Bedside echogram in ischaemic bowel. BMJ Case Reports. 2009:bcr.2007.053462 [Citation ends].
plain abdominal x-rays:
may see dilated loops of bowel; air-fluid level; bowel wall thickening; formless loops of large or small bowel; pneumatosis; vascular gas
More
chest x-ray:
may see free air under the diaphragm
More
FBC:
elevated WBC count
More
WBC count may be >15.0 × 10⁹/L (>15,000 cells/microL).
More than 90% of patients have leukocytosis.[90]
Normal WBC count does not exclude diagnosis.
serum lactate:
elevated
More
ABG:
metabolic acidosis
serum electrolytes:
uraemia, elevated creatinine

Other investigations

mesenteric angiography:
arterial or venous obstruction
More

Ischaemic bowel disease

Myocardial infarction

History

epigastric pain, diaphoresis, shortness of breath, nausea, vomiting; may be risk factors such as atherosclerosis, diabetes, smoking, hypertension, obesity, dyslipidaemia; atypical symptoms more common in women, older people, and those with diabetes

Exam

often normal; may be tachycardia, bradycardia, hypotension, third and fourth heart sound, paradoxical splitting of second heart sound

1st investigation

ECG:
ST-T wave changes or ischaemic changes
cardiac troponins:
>99th percentile of normal

Other investigations

Overview of acute coronary syndrome

Meckel's diverticulitis

History

sudden-onset severe abdominal pain, often starts periumbilical with migration to right lower quadrant; nausea, vomiting, anorexia, fever, diarrhoea

Exam

fever, tachycardia, patient may be lying in right lateral decubitus position with hips flexed; no or decreased bowel sounds; pain commonly originates near the umbilicus or the epigastrium; right lower quadrant (McBurney's point) tenderness with rigid abdomen; guarding and rebound tenderness; psoas sign (right lower quadrant pain with right thigh extension)

1st investigation

FBC:
low haemoglobin and haematocrit; leukocytosis with left shift
technetium-99m pertechnetate scan ('Meckel scan'):
ectopic focus or 'hot spot'; enhancement of diverticulum

Other investigations

plain abdominal radiography:
dilated bowel loops with air-fluid levels and paucity of distal gas suggests bowel obstruction; free air on upright film suggests a perforation; a density in the right side of the abdomen suggests an intussusception
CT scan of the abdomen and pelvis:
blind-ending fluid-filled and/or gas-filled structure in continuity with distal ileum
ultrasound of the abdomen:
tubular mass in longitudinal views and a doughnut or target appearance in transverse views suggests intussusception

Meckel's diverticulum

Hepatic abscess

History

biliary tract abnormalities; age >50 years; malignancy; diabetes mellitus; history of interventional biliary or hepatic procedures; travel to endemic area for amoebiasis; right upper quadrant pain, fever, chills, anorexia, and malaise; nausea and vomiting; cough, shortness of breath, may have had recent episode of gastrointestinal disease or biliary disease such as appendicitis, diverticulitis, or cholangitis

Exam

fever; hepatomegaly; weight loss; shortness of breath; jaundice; pleural effusion right lower zone; signs of shock with severe disease; rarely ascites

1st investigation

FBC:
leukocytosis, elevated neutrophil count, anaemia
LFTs:
elevated alkaline phosphatase, mildly elevated aminotransferases and bilirubin, hypoalbuminaemia
blood culture:
pyogenic: may be positive for causative bacterial organism; fungal: may be positive for Candida species
prothrombin time and activated partial thromboplastin time:
usually normal
CRP:
may be elevated
chest x-ray:
in presence of pleural effusion: blunting of the costophrenic angles
liver ultrasound:
demonstrates a variably echoic lesion
contrast-enhanced abdominal CT scan:
demonstrates hypodense liver lesions; gas within the lesion is highly suggestive of a pyogenic abscess
More
Can provide information of extent of abscess and likely pathology.[Figure caption and citation for the preceding image starts]: Liver abscess: CT scan showing a liver abscess (7 cm x 5 cm) in a 46-year-old man who presented with fever, fatigue, and coughFrom the collection of Massachusetts General Hospital radiology images [Citation ends].[Figure caption and citation for the preceding image starts]: Liver abscess: CT scan showing 8 cm by 8 cm superinfected and ruptured echinococcal cyst, and a 4 cm by 4 cm echinococcal cyst in a 69-year-old man who presented with hypotension and chest pain radiating to the epigastric regionFrom the collection of MGH Massachusetts General Hospital radiology images [Citation ends].[Figure caption and citation for the preceding image starts]: Liver abscess: CT scan (coronal view) showing liver abscess in a 46-year-old man who presented with fever, fatigue, and coughFrom the collection of Massachusetts General Hospital radiology images [Citation ends].[Figure caption and citation for the preceding image starts]: Liver abscess: A non-contrast abdominal CT scan showing a huge gas-containing liver abscess (arrow)Adapted from BMJ Case Reports 2009 (doi:10.1136/bcr.08.2008.0638) [Citation ends].[Figure caption and citation for the preceding image starts]: Liver abscess: Gross pathology of amoebic abscess of liver; tube of 'chocolate' pus from abscessCDC; Dr. Mae Melvin; Dr E. West of Mobile, AL [Citation ends].
stool Entamoeba histolytica antigen detection test:
positive in amoebiasis
Gram stain and culture of aspirated abscess fluid:
pyogenic: positive for causative bacterial organism; fungal: may be positive for Candida species
polymerase chain reaction (PCR) or real-time quantitative PCR of aspirated abscess fluid:
amplification of amoebic DNA

Other investigations

pregnancy test:
negative
More

Liver abscess

Psoas abscess

History

fever, chills, nausea, vomiting, flank or low abdominal/groin pain, malaise; new-onset limp

Exam

mild pyrexia, rigors, flank or abdominal tenderness; hip flexion deformity; pain with active hip flexion and passive extension

1st investigation

FBC:
elevated WBC count
CRP:
elevated
CT abdomen/pelvis with intravenous contrast:
visualisation of abscess

Other investigations

ultrasound abdomen/pelvis:
visualisation of abscess
MRI abdomen/pelvis:
visualisation of abscess
aspiration of abscess, Gram stain and culture:
may culture causative organism

Tuberculosis

History

male, black or Hispanic ethnicity; diffuse abdominal pain, right lower quadrant pain

Exam

fever, cachexia, abdominal swelling, abdominal mass, hepatosplenomegaly, lymphadenopathy

1st investigation

chest x-ray:
consolidation, pulmonary infiltrates, mediastinal or hilar lymphadenopathy, upper zone fibrosis
More
sputum acid-fast bacilli smear and culture:
presence of acid-fast bacilli (Ziehl-Neelsen stain) in specimen
More
Testing of 3 specimens (minimum 8 hours apart, including an early morning specimen) is recommended in many countries; consult local guidance.[113]
Sputum specimen should be tested in patients with suspected extrapulmonary TB, as active pulmonary TB is seen in 15% to 20% of patients with extrapulmonary TB.[114][115][116]
Culture of Mycobacterium tuberculosis typically takes several weeks (up to 8), decisions on treatment are usually made before culture results are known.
acid-fast bacilli smear and culture of extrapulmonary biopsy specimen:
positive
More
Microscopy should be performed on specimens collected from sites of suspected extrapulmonary TB.[113][117]
Patients in whom urogenital-TB is suspected should have three early morning urines on consecutive days sent for AFB microscopy and culture.[118] Culture result may take several weeks.
nucleic acid amplification tests (NAAT):
positive for M tuberculosis
More
Although NAATs were originally designed and approved for respiratory specimens, they may also be requested on specimens from other sites where involvement of TB is suspected (e.g., cerebrospinal fluid, lymph node aspirate, lymph node biopsy, pleural fluid, peritoneal fluid, pericardial fluid, synovial fluid or urine).[113][119]
In the US, use of NAATs for extrapulmonary specimens is not approved by the Food and Drug Administration, and use would be off-label.
Several rapid NAATs are available for the diagnosis of TB and some are also able to detect genes encoding resistance to TB drugs.[119]

Other investigations

lateral flow urine lipoarabinomannan (LF-LAM) assay:
positive
More
One Cochrane review found the lateral flow urine lipoarabinomannan (LF-LAM) assay to have a sensitivity of 42% in diagnosing TB in HIV-positive individuals with TB symptoms, and 35% in HIV-positive individuals not assessed for TB symptoms.[120] WHO recommends that LF-LAM can be used to assist in the diagnosis of active TB in HIV-positive adults, adolescents, and children with signs and symptoms of TB, or in those with advanced HIV or who are seriously ill.[119]
Culture would still be required for drug susceptibility testing (DST).

Extrapulmonary tuberculosis

Oesophageal perforation (Boerhaave’s syndrome)

History

history of vomiting followed by chest pain; recent oesophagogastroduodenoscopy or chest/neck trauma; neck, chest, epigastric, or upper back pain; dysphagia; respiratory distress; fever, tachycardia

Exam

mediastinal crunching sound on auscultation; subcutaneous emphysema of neck or chest; decreased breath sounds (usually on left side); tachypnoea and respiratory distress

1st investigation

FBC:
elevated WBC count
erect chest x-ray:
may show pneumomediastinum, subcutaneous emphysema, pleural effusions typically located left side

Other investigations

contrast oesophagram:
visualisation of perforation
More
CT chest with oral and intravenous contrast:
visualisation of perforation
More
upper gastrointestinal endoscopy:
visualisation of perforation

Fitz-Hugh Curtis syndrome

History

female with history of pelvic inflammatory disease; severe right upper quadrant abdominal pain, possibly referred to right shoulder and worse on coughing, sneezing, or movement; fever, chills; headaches; malaise; hiccups; night sweats, nausea, and vomiting

Exam

right upper quadrant pain and tenderness on palpation; lower abdominal tenderness, cervical excitation pain, tender adnexa

1st investigation

ultrasound right upper quadrant:
no gallstones
CT abdomen/pelvis with oral and intravenous contrast:
may show enhancement of liver capsule
nucleic acid amplification test or culture of vaginal secretions:
may culture Neisseria gonorrhoeae or Chlamydia trachomatis

Other investigations

diagnostic laparoscopy with lysis of adhesions and peritoneal cultures:
may see peritonitis of liver surface and adjacent peritoneal surface; lysis of adhesions may provide relief of chronic symptoms; may culture N gonorrhoeae or C trachomatis
pregnancy test:
negative
More

Pelvic inflammatory disease

Ischaemic colitis

History

fever, vomiting, diarrhoea, abdominal pain, and bloody stools; history of vascular disease, recent abdominal aortic aneurysm repair, sepsis, myocardial infarct, or atrial fibrillation

Exam

diffuse abdominal pain or localised to area of colon affected with little or no distension

1st investigation

FBC:
elevated WBC count
serum lactate:
elevated if tissue hypoxia
CT abdomen/pelvis with oral and intravenous contrast:
may show thickened and inflamed segments of colon; pneumatosis or gas in mesenteric veins suggestive of ischaemia
colonoscopy:
pale or bluish mucosa with haemorrhagic lesions

Other investigations

obstruction series:
pneumatosis or gas in mesenteric or portal vein but not specific to ischaemic colitis
MRI abdomen with contrast:
may show thickened and inflamed segments of colon; pneumatosis or gas in mesenteric veins suggestive of ischaemia
diagnostic laparoscopy:
full thickness ischaemia may be seen; ischaemia restricted to mucosa will not be seen

Ischaemic bowel disease

Ruptured splenic artery aneurysm

History

females and pregnant women; acute abdominal pain, may start in epigastrium or left upper quadrant and become diffuse; occasionally presents as gastrointestinal haemorrhage; dizziness, weakness, collapse

Exam

hypovolaemic shock; pallor; abdominal distension and tenderness

1st investigation

CT abdomen/pelvis with intravenous contrast:
visualisation of aneurysm and haemorrhage
More

Other investigations

Budd-Chiari syndrome

History

female, age in third or fourth decade of life; use of oral contraceptive, pregnancy, and immediate postpartum period; history of myeloproliferative disorder and/or hypercoagulable states; right upper quadrant pain, history of liver failure/cirrhosis, variceal bleeding, ascites

Exam

right upper quadrant pain and tenderness; hepatosplenomegaly; jaundice; muscle wasting; ascites; leg oedema; truncal venous collaterals; disturbances of consciousness, intellectual function, behaviour, and neuromuscular function (hepatic encephalopathy)

1st investigation

colour-flow Doppler ultrasound:
alterations in hepatic and/or caval veins in the form of thrombosis, stenosis, fibrotic cord, or insufficient recanalisation of the vessels
More

Other investigations

MRI with pulsed sequencing:
thrombus, compression, and/or stenosis along the whole length of the inferior vena cava (IVC) or hepatic veins; necrosis and focal nodular hyperplasia in liver parenchyma; detect other lesions
More
CT abdomen/pelvis with triple-phase contrast:
occlusion of hepatic veins and/or IVC; areas with necrotic liver parenchyma; detect other lesions
hepatic venography:
spider web pattern
More
Definitive investigation, but invasive so performed only if non-invasive studies negative and still clinically suspicious Budd-Chiari syndrome.[Figure caption and citation for the preceding image starts]: Budd-Chiari syndrome: Hepatic venogram demonstrating 'spider web' and thrombus in the inferior vena cavaLiver Transplantation Journal. 2006 Nov;12(11 suppl 2):S21-2; reprinted with permission of John Wiley & Sons, Inc [Citation ends].

Budd-Chiari syndrome

Splenic infarct

History

ranges from asymptomatic to left upper quadrant pain, nausea, vomiting, fever, chills; may have pleuritic chest pain or left shoulder pain

Exam

tender left upper quadrant

1st investigation

CT abdomen/pelvis with intravenous contrast:
visualisation of infarct

Other investigations

MRI abdomen/pelvis intravenous gadolinium contrast:
visualisation of infarct

Abdominal wall haematoma

History

spontaneous or secondary to trauma, exercise, coughing, or procedure; acute abdominal pain with fever, nausea, vomiting; may report a mass or lump

Exam

signs of hypovolaemia with hypotension and tachycardia; localised abdominal pain and tenderness with non-pulsatile mass that is firm and painful; no mass may be palpable depending on location and depth of haematoma

1st investigation

ultrasound abdominal wall:
haematoma visualised
More

Other investigations

CT abdomen/pelvis with intravenous contrast:
haematoma visualised
More
FBC:
normal or low haemoglobin
coagulation studies:
normal or deranged

Uraemia

History

confusion, depressed mental status; oliguria; tachycardia; pallor; fatigue; diffuse abdominal pain; thirst; excessive urination at night

Exam

diffuse abdominal pain, poor skin turgor, low blood pressure

1st investigation

creatinine clearance:
reduced, usually <10 mL/min
glomerular filtration rate:
reduced
serum electrolytes:
abnormal
urinalysis:
abnormal

Other investigations

CT abdomen/pelvis with oral and intravenous contrast:
may reveal alternative cause for acute abdomen

Addisonian crisis

History

weight loss, nausea, vomiting, abdominal pain, anorexia, salt craving, fatigue, postural dizziness, syncope, confusion

Exam

cutaneous and mucosal hyperpigmentation, hypotension, pyrexia, and abdominal pain and/or guarding

1st investigation

random cortisol level:
decreased
rapid adrenocorticotropic hormone (ACTH) stimulation test:
limited increase in cortisol levels in response to ACTH stimulation
CT abdomen/pelvis with oral and intravenous contrast:
may show bilateral enlargement of adrenal glands, adrenal haemorrhage, infiltrating diseases, or atrophic glands; may rule out other causes of abdominal pain and hypotension
serum electrolytes:
often abnormal, typically with hypercalcaemia, hyponatremia, and hyperkalaemia

Other investigations

Addison's disease

Hypercalcaemia

History

bone pain; depression; fatigue; confusion; nausea, anorexia; constipation; abdominal or flank pain; polyuria, polydipsia

Exam

non-specific findings; abdominal pain, hyperreflexia, tongue fasciculations, bony tenderness on palpation; hypertension and bradycardia

1st investigation

corrected or ionised calcium:
elevated
12-lead ECG:
typically short QT interval and widened T waves
serum parathyroid hormone:
elevated

Other investigations

ultrasound neck:
may indicate hyperparathyroidism
nuclear scan neck:
may indicate hyperparathyroidism
MRI neck:
may indicate hyperparathyroidism
CT abdomen/pelvis with oral and intravenous contrast:
may indicate alternative source of acute abdomen

Assessment of hypercalcaemia

Acute intermittent porphyria (AIP)

History

family history of acute porphyria, female sex predominates, nutritional alterations (e.g., fasting, dieting), intercurrent illness, and exposure to drugs or hormones known to provoke attacks of AIP; intermittent acute severe abdominal pain for days with symptoms out of proportion to the physical examination, often epigastric and colicky; nausea, vomiting; psychiatric symptoms (minor behavioural changes and insomnia to depression, agitation, and confusion); weakness in lower limbs; constipation; urinary hesitancy and dysuria

Exam

epigastric pain, tenderness, distension; fever, tachycardia, and hypertension; dark or red urine; central nervous system signs such as seizures, mental status changes, cortical blindness, and coma; weakness starting in lower limbs and ascending

1st investigation

urinary porphobilinogen (PBG):
elevated; reddish colour
More

Other investigations

obstruction series:
may show ileus
CT abdomen/pelvis with oral and intravenous contrast:
may indicate alternative source of acute abdomen

Acute intermittent porphyria

Familial Mediterranean fever

History

mainly people of Mediterranean ancestry, especially from Arabian countries, Turkey, and Armenia; age <20 years; male sex; positive family history; episodic acute fever and pain in various places, the abdomen being the most common; pain can also occur in chest, joints, muscles, and skin; altered bowel habit (usually constipation)

Exam

fever, tachypnoea, acute abdominal pain with rigidity, rebound tenderness

1st investigation

FBC:
leukocytosis ± thrombocytosis
erythrocyte sedimentation rate:
elevated
CRP:
elevated
serum fibrinogen:
elevated
LFTs:
rarely: elevated alanine aminotransferase and aspartate aminotransferase
urinalysis:
proteinuria; haematuria suggests infection or vasculitis
CT abdomen:
serositis; may show fluid and/or inflammation

Other investigations

genetic testing:
positive for mutation
pregnancy test:
negative
More

Familial Mediterranean fever

Typhlitis (neutropenic enterocolitis)

History

history of haematological malignancy and/or receiving chemotherapy or other immunosuppressive medicines; fever, abdominal pain, particularly right lower quadrant; nausea, vomiting, diarrhoea (sometimes bloody)

Exam

pyrexia; hypovolaemia from dehydration; marked abdominal pain and tenderness; may have septic shock; peritonitis

1st investigation

CT abdomen/pelvis with oral and intravenous contrast:
dilated/distended caecum with thickening and inflammation; may show pneumatosis, localised perforation, phlegmon, or abscess formation
More
absolute neutrophil count:
neutropenia
blood cultures:
may culture infective organism
stool culture (including Clostridium difficile toxin):
may culture infective organism

Other investigations

ultrasound abdomen:
may show distended caecum; free fluid
obstruction series:
usually non-specific; may show distended caecum and thumbprinting or pneumatosis
diagnostic laparoscopy:
direct visualisation of pathology
More
pregnancy test:
negative
More

Radiation enteritis

History

history of radiation treatment in recent or distant past; acute radiation enteritis produces nausea, vomiting, abdominal pain, diarrhoea, anorexia, diarrhoea/watery stools; chronic radiation enteritis produces obstructive symptoms (distention, nausea, vomiting, reduced flatus) if stricturing has occurred or malabsorptive symptoms (bloating, cramping, flatus, bulky stools, diarrhoea, weight loss) if mucosal integrity has been damaged; gastrointestinal bleeding if intestinal ulceration has occurred

Exam

abdominal pain and tenderness without distension in acute enteritis; passage of blood or mucus per rectum; obstructive findings include distension with tenderness and guarding, tympanism, tinkling bowel sounds, dehydration; abdominal bloating, mild abdominal tenderness; steatorrhoea, weight loss with malabsorption

1st investigation

CT abdomen/pelvis with oral and intravenous contrast:
thickening and inflammation of bowel segments affected

Other investigations

upper gastrointestinal series with small bowel follow-through:
shows extent of radiation injury; stricturing of bowel; fistula formation; thickening of bowel wall
enteroclysis:
shows extent of radiation injury; stricturing of bowel; fistula formation; thickening of bowel wall
More
endoscopy:
shows mucosal integrity
More

Heavy metal poisoning

History

medical/environmental/occupational history consistent with exposure; nausea, persistent vomiting, diarrhoea, abdominal pain

Exam

anaemia, dehydration, neurological findings, abdominal pain and tenderness; encephalopathy, cardiomyopathy, dysrhythmias, acute tubular necrosis, and metabolic acidosis

1st investigation

FBC with blood smear:
haematocrit and haemoglobin values reduced; smear either normochromic and normocytic or hypochromic and microcytic
serum electrolytes and urea:
may be normal or deranged
LFTs:
normal or elevated
urinalysis:
presence of heavy metal at elevated levels
venous blood lead level:
elevated in lead exposure

Other investigations

Lead toxicity

Spider bite

History

possible spider bite (e.g., black widow spider); fever, chills, nausea, vomiting, and severe, acute diffuse abdominal pain

Exam

diffuse abdominal pain and tenderness; abdominal muscle rigidity; profuse sweating; tachycardia

1st investigation

clinical diagnosis:
diagnosis is based on history and examination

Other investigations

Insect bites and stings

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Assessment of acute abdomen

Differentials

Common

Adhesions

History

Exam

1st investigation

Other investigations

Incarcerated/strangulated hernia

History

Exam

1st investigation

Other investigations

Cholecystitis

History

Exam

1st investigation

Other investigations

Perforated gastric ulcer

History

Exam

1st investigation

Other investigations

Appendicitis

History

Exam

1st investigation

Other investigations

Ectopic pregnancy

History

Exam

1st investigation

Other investigations

Pelvic inflammatory disease

History

Exam

1st investigation

Other investigations

Acute pancreatitis

History

Exam

1st investigation

Other investigations

Acute diverticulitis

History

Exam

1st investigation

Other investigations

Ulcerative colitis

History

Exam

1st investigation

Other investigations

Crohn's disease

History

Exam

1st investigation

Other investigations

Cholelithiasis

History

Exam

1st investigation

Other investigations

Gastrointestinal malignancy

History

Exam

1st investigation

Other investigations

Mallory-Weiss tear

History

Exam

1st investigation

Other investigations

Diabetic ketoacidosis

History

Exam

1st investigation

Other investigations

Opioid withdrawal

History