Differentials

Common

GERD

History

burning epigastric/chest pain, regurgitation, worse with some foods and recumbency; improved by antacids

Exam

enamel erosion

1st investigation
  • therapeutic trial of proton pump inhibitors:

    relief of symptoms

    More
Other investigations
  • esophagogastroduodenoscopy (EGD):

    esophagitis or other abnormality explaining pain

    More
  • 24-hour pH probe testing:

    increased acid exposure to esophagus correlated with symptom occurrence

Peptic ulcer disease

History

epigastric pain, may be worsened or relieved by food; pain often worse at night; bloody or coffee-ground emesis or dark black tarry stool indicative of active bleeding and requiring urgent endoscopic evaluation; nonsteroidal anti-inflammatory drug (NSAID) and alcohol use predispose to ulcer disease; Helicobacter pylori more common in certain ethnicities, especially South and Central Americans and Asians

Exam

epigastric tenderness, pallor, Hemoccult-positive stool or black tarry stool

1st investigation
  • esophagogastroduodenoscopy:

    visualization of gastric or duodenal ulcer

    More
Other investigations

    Infectious gastroenteritis

    History

    history of travel to endemic areas; greasy, foul-smelling stools; diarrhea (may be bloody, depending on organism, but most chronic forms are nonbloody); tenesmus, fever, chills; immunosuppressed patients at higher risk

    Exam

    exam is nonspecific

    1st investigation
    • stool culture:

      positive culture for Escherichia coli, Shigella, Salmonella, or Campylobacter

    • stool ova and parasites:

      positive

    Other investigations
    • stool assay for Clostridium difficile toxin:

      positive

      More
    • sigmoidoscopy/colonoscopy with biopsy:

      microbiologic and/or histologic confirmation of infection

      More

    Lactase deficiency

    History

    abdominal pain, bloating, gas, and/or loose stool after ingestion of dairy products (or any product that contains the sugar lactose)[70]

    Exam

    exam is nonspecific

    1st investigation
    • trial of dietary lactose elimination:

      resolution of symptoms once lactose-containing dairy and nondairy products are eliminated from diet; resumption of symptoms when reintroduced

    Other investigations
    • lactose breath test:

      rise in breath hydrogen above normal

    Chronic cholecystitis, Chronic cholelithiasis

    History

    colicky right upper quadrant (RUQ) pain, fever, jaundice, symptoms beginning 30 minutes to 1 hour after eating and worse with high-fat meals (usually a source of acute abdominal pain; however, patients can have a chronic cholecystitis or acute recurrent cholecystitis with passage of microcalculi, sludge, or small stones)

    Exam

    fever, scleral icterus, jaundice, RUQ tenderness, positive Murphy sign

    1st investigation
    • LFT:

      elevated in an obstructive pattern (alk phos and gamma GT 2-10 times normal); elevated total bilirubin

      More
    • RUQ ultrasound:

      pericholecystic fluid, gallbladder wall thickening, common bile duct dilation, cholelithiasis

    Other investigations

      Nephrolithiasis

      History

      colicky flank pain that radiates to groin; nausea; bloody or amber urine; history of renal stones or recurrent urinary tract infections; may present as episodes of recurrent acute pain versus chronic pain

      Exam

      tenderness on deep abdominal palpation or with back tapping, usually unilateral; hematuria

      1st investigation
      • urinalysis:

        blood (macro- or microscopic)

      • noncontrast CT abdomen:

        hydronephrosis, obstructing stone

      • stone analysis:

        stones/debris sent for analysis to determine etiology of nephrolithiasis

      Other investigations
      • renal ultrasound:

        urinary tract calcification or dilation

        More

      Pelvic inflammatory disease (PID)

      History

      fever, pelvic pain, vaginal discharge, painful intercourse, history of sexually transmitted infection or intrauterine device use[85]

      Exam

      adnexal tenderness, vaginal discharge, cervical motion tenderness, cervical discharge, friable cervix, erythematous cervix

      1st investigation
      • CBC:

        leukocytosis

      • C-reactive protein:

        elevated

      • erythrocyte sedimentation rate:

        elevated

      • gonococcal and chlamydia culture or nucleic acid amplification test:

        presence of organism

      Other investigations
      • pelvic ultrasound:

        classic signs are 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 also see tubo-ovarian abscess

      Irritable bowel syndrome

      History

      abdominal pain relieved with defecation; pain associated with alteration of bowel habit (change in stool frequency and/or form); exacerbated by psychosocial stressors[31]

      Exam

      usually normal

      1st investigation
      • clinical diagnosis:

        other causes of abdominal pain excluded

        More
      Other investigations
      • fecal calprotectin:

        <50 micrograms/g makes inflammatory bowel disease unlikely, and irritable bowel syndrome more likely[41]

      Gastroparesis

      History

      early satiety, fullness, nausea, vomiting; all symptoms are worse after ingestion of meals; history of diabetes mellitus or Parkinson disease; previous abdominal surgery that may result in vagal nerve injury

      Exam

      succussion splash rarely detected; weight loss; no other specific physical findings

      1st investigation
      • gastric emptying scintigraphy:

        gastric retention of >10% of the test meal at the end of 4 hours, or >60% retention after 2 hours supports a diagnosis of gastroparesis[87][88]

        More
      Other investigations
      • wireless capsule motility:

        gastric emptying time >5 hours is consistent with gastroparesis[89]​​

        More

      Functional dyspepsia

      History

      bothersome postprandial fullness, early satiation; epigastric pain and burning that are unexplained after a routine clinical evaluation; may be associated with nausea and vomiting, and exacerbated by psychosocial stressors[36]

      Exam

      usually normal

      1st investigation
      • clinical diagnosis:

        other causes of abdominal pain excluded

        More
      Other investigations

        Centrally mediated abdominal pain syndrome (CAPS)

        History

        chronic abdominal pain without obvious organic etiology, not affected by eating or defecation, exacerbated by psychosocial stressors

        Exam

        usually normal

        1st investigation
        • clinical diagnosis:

          other causes of abdominal pain excluded

          More
        Other investigations

          Chronic abdominal wall pain

          History

          localized anterior abdominal pain accentuated by physical activity

          Exam

          positive Carnett test to show precise localization of the pain[29]

          1st investigation
          • clinical and physical examination:

            abdominal imaging by ultrasound, CT, or MRI may be needed to exclude internal organ pathology or abdominal hernia (e.g., Spigelian hernia)

          Other investigations

            Referred pain

            History

            abdominal pain can be referred from multiple extra-abdominal sources, including the chest (e.g., angina, pneumonia, pleurisy, malignancy), musculoskeletal structures (e.g., rib fracture, abdominal cutaneous nerve entrapment), nerves (e.g., herpes zoster, radiculopathy), or pelvis (e.g., interstitial cystitis, endometriosis, ectopic pregnancy, gynecological malignancies such as ovarian cancer, adhesions, urethral syndrome, changes or dysfunction of the pelvic muscles, prostatitis, prostate cancer), and intermittent/recurrent testicular torsion

            Exam

            exam varies depending on underlying etiology

            1st investigation
            • directed by suspected source of referred pain:

              may include imaging of spine, chest, or pelvis

            Other investigations

              Uncommon

              Crohn disease

              History

              crampy abdominal pain, often localized to the right lower quadrant and worse postprandially;[62] intermittent diarrhea, bloody diarrhea if colitis a feature, weight loss, fatigue, family history of inflammatory bowel disease

              Exam

              aphthous ulcers, evidence of weight loss, pallor, abdominal tenderness, abdominal mass, perianal fistula, perirectal abscess, anal fissure, perianal skin tags; extraintestinal manifestations including iritis, arthritis, sacroiliitis, erythema nodosum, pyoderma gangrenosum

              1st investigation
              • colonoscopy:

                aphthous ulcers, hyperemia, edema, cobblestoning, skip lesions

                More
              • CBC:

                microcytic anemia, thrombocytosis

              • erythrocyte sedimentation rate/C-reactive protein:

                elevated

              Other investigations
              • upper gastrointestinal series, small bowel follow-through, and enteroclysis:

                evidence of enteritis, small bowel wall thickening, fat stranding

                More
              • small bowel capsule endoscopy:

                aphthous ulcers, hyperemia, edema, cobblestoning, skip lesions

                More

              Ulcerative colitis

              History

              bloody diarrhea, watery diarrhea, weight loss, abdominal pain, mucus per rectum, urgency and tenesmus; weight loss indicates more severe disease[68]

              Exam

              evidence of weight loss, pallor, abdominal tenderness, abdominal mass, iritis, arthritis, sacroiliitis, erythema nodosum, pyoderma gangrenosum

              1st investigation
              • flexible sigmoidoscopy:

                rectal involvement, continuous colonic involvement, diffuse erythema, mucosal granularity

                More
              • CBC:

                microcytic anemia, thrombocytosis

              • erythrocyte sedimentation rate/C-reactive protein:

                elevated

              Other investigations
              • colonoscopy:

                rectal involvement, continuous colonic involvement, diffuse erythema, mucosal granularity; backwash ileitis may be present in pancolitis

                More

              Subacute intestinal obstruction

              History

              abdominal pain with features of obstruction including, but not limited to, constipation, obstipation, and nausea with bilious or feculent emesis; history of abdominal surgery, radiation, or hernia

              Exam

              high-pitched bowel sounds, absence of bowel sounds, abdominal scars, hernia

              1st investigation
              • abdominal x-ray:

                dilated loops of bowel, air-fluid levels, no air in rectum

              Other investigations
              • CT abdomen:

                obstruction, hernia, transition point at site of obstruction, volvulus

              Celiac disease

              History

              nonspecific abdominal pain, bloating; diarrhea; greasy, foul-smelling stools; weight loss; anemia, ataxia, osteoporosis

              Exam

              pale conjunctiva, aphthous stomatitis, dermatitis herpetiformis, ataxia

              1st investigation
              • total IgA:

                may be normal or deficient

                More
              • IgA-tTG (tissue transglutaminase):

                elevated

                More
              • esophagogastroduodenoscopy:

                atrophy and scalloping of mucosal folds; nodularity and mosaic pattern of mucosa

              • small bowel biopsy:

                presence of intraepithelial lymphocytes, villous atrophy, and crypt hyperplasia

                More
              Other investigations
              • CBC:

                microcytic anemia

              • iron studies:

                iron deficiency

              • endomysial antibody (EMA):

                elevated

                More
              • IgG-based antibodies:

                elevated

                More

              Chronic pancreatitis

              History

              chronic postprandial pain; history of recurrent acute pancreatitis, alcohol misuse, or smoking;[71] brittle diabetes; greasy, foul-smelling stools and weight loss suggest exocrine insufficiency

              Exam

              weight loss, epigastric tenderness consistent with the diagnosis but not diagnostic, and palmar erythema suggest alcohol misuse

              1st investigation
              • serum amylase and lipase:

                elevated (3 times the upper limit of normal)

                More
              • CT abdomen:

                atrophic, calcified pancreas; pancreatic duct abnormalities, strictures, pseudocysts

              Other investigations
              • endoscopic ultrasonography:

                ductal and parenchymal abnormalities

                More
              • therapeutic trial of pancreatic enzyme replacement:

                improvement in symptoms

                More

              Esophageal cancer

              History

              weight loss, dysphagia, history of Barrett esophagitis

              Exam

              signs of weight loss, pallor, stool that is positive for occult blood

              1st investigation
              • esophagogastroduodenoscopy:

                visualization of esophageal cancer

                More
              Other investigations
              • CT abdomen:

                extent of disease, metastatic lesions

              Gastric cancer

              History

              weight loss, early satiety, nausea and vomiting, dysphagia if proximal lesion

              Exam

              signs of weight loss, pallor, palpable abdominal mass, palpable periumbilical or supraclavicular lymph nodes, Hemoccult-positive stool

              1st investigation
              • esophagogastroduodenoscopy:

                visualization of gastric cancer

                More
              Other investigations
              • CT abdomen:

                extent of disease, metastatic lesions

              Colorectal cancer

              History

              weight loss, blood in stool, change in bowel habit, anemia

              Exam

              signs of weight loss, pallor, palpable abdominal mass, hepatomegaly if metastatic spread has occurred, multiple seborrheic keratoses (sign of Lesser-Trelat, a rare sign associated with adenocarcinoma), occult blood-positive in stool​​​

              1st investigation
              • colonoscopy:

                visualization of colorectal mass

                More
              • quantitative fecal immunochemical tests:

                positive

                More
              Other investigations
              • CT abdomen:

                extent of disease, metastatic lesions

              Pancreatic cancer

              History

              weight loss, epigastric pain, depression, jaundice, history of chronic pancreatitis

              Exam

              signs of weight loss, palpable abdominal mass, jaundice

              1st investigation
              • CT abdomen:

                pancreatic mass, dilated pancreatic duct

              Other investigations
              • endoscopic retrograde cholangiopancreatography (ERCP)/magnetic resonance cholangiopancreatography (MRCP):

                dilated pancreatic duct

                More

              Hepatocellular cancer

              History

              weight loss, jaundice, history of cirrhosis

              Exam

              signs of weight loss, jaundice, tender hepatomegaly

              1st investigation
              • multiphase CT or MRI abdomen:

                hepatic mass with hypervascular pattern

                More
              Other investigations
              • alpha fetoprotein:

                elevated

                More

              Cholangiocarcinoma

              History

              weight loss, jaundice

              Exam

              signs of weight loss, jaundice

              1st investigation
              • abdominal ultrasound:

                intrahepatic duct dilation

              • liver tests:

                elevated alkaline phosphatase and serum gamma-GT (obstructive/cholestatic pattern); conjugated bilirubin elevated in obstructive jaundice

              Other investigations
              • endoscopic retrograde cholangiopancreatography (ERCP)/magnetic resonance cholangiopancreatography (MRCP):

                intrahepatic duct dilation, filling defect visualized

                More
              • serum CA 19-9:

                elevated

                More

              Ovarian cancer

              History

              symptoms are often vague and nonspecific; common symptoms are abdominal bloating, nausea and emesis, early satiety, dyspepsia, increased abdominal girth, abdominal cramping, or a change in bowel habit suggestive of advanced disease

              Exam

              variable: may include ascites, pleural effusion, palpable mass on pelvic exam, and abdominal distension that is dull to percussion; patients may appear malnourished if they have significant gastrointestinal symptoms; findings consistent with ascites (e.g., fluid wave, shifting dullness) or a right-sided pleural effusion (e.g., diminished breath sounds or rales present) can often be detected; on pelvic exam, a mass might be appreciated in the adnexa or rectovaginal space

              1st investigation
              • serum CA-125:

                ≥35 IU/mL

                More
              Other investigations
              • ultrasound of abdomen and pelvis:

                presence of solid, complex, septated, multiloculated mass; high blood flow

                More

              Chronic mesenteric ischemia

              History

              chronic recurrent abdominal pain, usually worse after eating (referred to as abdominal angina); may lead to food phobia and weight loss; acute presentation with abdominal pain and bloody diarrhea may be secondary to acute ischemic colitis; presence of risk factors for vascular disease including diabetes, hypertension, renal disease, cardiovascular disease, and/or smoking[79]

              Exam

              subjective complaint of abdominal pain out of proportion to exam findings; signs of peripheral vascular disease may be present, such as diminished peripheral pulses or cool extremities; with severe atherosclerotic disease, an abdominal bruit may be heard

              1st investigation
              • CT or MRI angiography, or duplex ultrasound of abdomen:

                stenosis, thrombus, or reduced blood flow in the celiac artery, superior mesenteric artery, or inferior mesenteric artery

                More
              Other investigations
              • abdominal arteriogram:

                diminished blood flow to the intestine

              Superior mesenteric artery syndrome

              History

              chronic postprandial abdominal pain that usually begins after a period of weight loss (the weight loss may be intentional and predate the pain), early satiety, bloating, nausea with bilious emesis

              Exam

              evidence of weight loss

              1st investigation
              • CT abdomen:

                loss of fat planes surrounding superior mesenteric and celiac arteries; compression of distal duodenum by superior mesenteric artery, with proximal dilation of small bowel

              • CT or MRI angiography, or duplex ultrasound of abdomen:

                stenosis, thrombus, or reduced blood flow in the celiac artery, superior mesenteric artery, or inferior mesenteric artery; signs of atherosclerosis

                More
              Other investigations
              • abdominal arteriogram:

                diminished blood flow at the superior mesenteric and celiac arteries

              Acute intermittent porphyria

              History

              abdominal pain with neuropsychiatric features[81]

              Exam

              urine may be pigmented

              1st investigation
              • 24-hour urine collection:

                elevated alpha-aminolevulinate and porphobilinogen >5-10 times upper limit of normal

              Other investigations

                Heavy metal poisoning (lead, arsenic)

                History

                pica, lead paint exposure, occupational exposure; abdominal pain may be severe[82]

                Exam

                exam may mimic an acute abdomen

                1st investigation
                • heavy metal toxicology tests:

                  elevated lead or arsenic levels

                Other investigations
                • CBC:

                  basophilic stippling of red cells, anemia

                Familial Mediterranean fever

                History

                positive family history, recurrent/chronic episodes of fever and serositis with pain in abdomen, chest, joints, and muscles; rash may be present[83]

                Exam

                exam may mimic an acute abdomen

                1st investigation
                • CBC:

                  leukocytosis

                • erythrocyte sedimentation rate/C-reactive protein:

                  elevated

                Other investigations
                • CT abdomen:

                  nonspecific mesenteric pathology, which may include engorged mesenteric vessels, thickened mesenteric folds, and mesenteric and/or retroperitoneal lymphadenopathy

                Paroxysmal nocturnal hemoglobinuria

                History

                severe abdominal pain, lethargy, dysphagia, erectile dysfunction[84]

                Exam

                possible evidence of venous thrombosis, peripheral edema, pallor

                1st investigation
                • CBC:

                  hemolysis, anemia, or cytopenia

                • LDH:

                  >20 times upper limit of normal

                • urine dipstick:

                  hemoglobinuria

                  More
                • urine microscopy:

                  hemosiderinuria

                  More
                Other investigations
                • CT abdomen:

                  venous thrombosis

                • bone marrow biopsy:

                  aplastic anemia

                  More

                Chronic pyelonephritis

                History

                dysuria, fever, flank pain; increased risk if underlying renal tract abnormalities (e.g., children with vesicoureteral reflux), episodes of recurrent acute pyelonephritis, inadequately treated acute pyelonephritis, or history of diabetes

                Exam

                fever, flank tenderness

                1st investigation
                • urinalysis:

                  positive for white blood cells and nitrates

                • CBC:

                  leukocytosis

                Other investigations
                • renal ultrasound/CT abdomen:

                  abscess

                Endometriosis

                History

                perimenstrual chronic pelvic/abdominal pain, dysmenorrhea, dyspareunia, dysuria, hematuria, urinary frequency

                Exam

                tender pelvic nodules, retroverted uterus, tender uterus

                1st investigation
                • clinical diagnosis:

                  history and examination findings in a female patient of reproductive age are usually sufficient for diagnosis

                Other investigations
                • pelvic ultrasound:

                  ovarian endometrioma, if present

                • laparoscopy with biopsy:

                  histologic confirmation of extrauterine endometrial tissue

                • MRI:

                  atypical symptoms (e.g., deep pelvic endometriosis)[86]

                Ovarian cystic disease

                History

                lower pelvis/abdominal discomfort, dyspareunia, may be cyclical, severe pain if torsion or hemorrhage into cyst

                Exam

                palpable mass on bimanual pelvic exam

                1st investigation
                • pelvic ultrasound:

                  cystic adnexal lesion, free fluid in the peritoneum

                Other investigations

                  Narcotic bowel syndrome

                  History

                  chronic narcotic use

                  Exam

                  usually normal

                  1st investigation
                  • clinical diagnosis:

                    other causes of abdominal pain excluded

                  Other investigations

                    Abdominal migraine

                    History

                    recurrent attacks of periumbilical or diffuse abdominal pain, lasting 1-72 hours, several times per year, accompanied by anorexia, nausea, vomiting, and pallor; few or no gastrointestinal complaints between attacks; migraine headaches in family and/or patient; exacerbation by stressors such as mental stress, tiredness, missing a meal, travel, and certain foods; usually occurs in childhood, with only few patients continuing to exhibit symptoms into adulthood[90]

                    Exam

                    usually normal

                    1st investigation
                    • clinical diagnosis:

                      other causes of abdominal pain excluded

                      More
                    Other investigations

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