Differentials
Peptic ulcer disease
SIGNS / SYMPTOMS
Longstanding epigastric pain, which does not generally radiate to the back; reflux; heartburn; and anorexia. Identifiable causes such as non-steroidal anti-inflammatory drug use, Helicobacter pylori, Zollinger-Ellison's syndrome may be present.
INVESTIGATIONS
May improve with proton pump inhibitors, lifestyle modifications, and H pylori treatment.
Normal or low lipase and amylase.
Endoscopic evaluation will be diagnostic after visualising erosions, erythema, or ulcers, and allows biopsies to be performed.
Perforated viscus
SIGNS / SYMPTOMS
Will present with acute abdomen, peritoneal signs, tachycardia, and sepsis. Generally the abdomen is rigid and tender in all 4 quadrants, with guarding.
INVESTIGATIONS
Normal or slightly elevated lipase.
Plain x-rays show sub-diaphragmatic air.
Oesophageal spasm
SIGNS / SYMPTOMS
Dysphagia, odynophagia, weight loss, history of retrosternal pain. Physical examination may be normal.
INVESTIGATIONS
A swallow study may demonstrate a contracted and abnormal-appearing oesophagus with increased pressures on oesophageal manometry.
Intestinal obstruction
SIGNS / SYMPTOMS
History of abdominal surgeries (especially colon resection, caesarean sections, and aortic procedures).
Hernias, usually with incarcerated bowel, in the physical examination.
Presents with abdominal distension (depends on the level of obstruction), tympanism, decreased bowel sounds, anorexia, emesis (quality depends on location of obstruction), obstipation, or constipation.
INVESTIGATIONS
Normal lipase and amylase.
Acute abdominal series will show air-fluid levels, distended bowel loops, absence of distal gas, pneumatosis.
An abdomen/pelvic CT scan may be more diagnostic, and will show point of transition and potentially identify aetiology (such as volvulus, hernias, intussusception, masses).
Abdominal aorta aneurysm
SIGNS / SYMPTOMS
Cardiovascular risk factors: hyperlipidaemia, tobacco, diabetes mellitus, homocystinaemia.
Acute tearing-like abdominal pain, pulsating abdominal mass, hypotension, and mottled lower extremities with decreased pulses and abdominal distension.
INVESTIGATIONS
High index of suspicion is necessary to make a rapid diagnosis and improve outcomes. In stable patients, where history and physical examination are equivocal, a CT angiography may be useful as a rapid way to make diagnosis.
If too unstable for radiographic evaluation, patients usually go directly to surgery.
Cholangitis
SIGNS / SYMPTOMS
Charcot's triad (jaundice, right upper quadrant pain, and fever) present in 70% of patients, altered mental status, and hypotension indicate biliary sepsis, usually caused by gram-negative bacteria.
Patient may have a history of gallstones, peri-ampullary neoplasms, or biliary manipulation such as endoscopic retrograde cholangiopancreatography.
INVESTIGATIONS
Several clinical findings are present more frequently in cholangitis, such as fever (95%), right upper quadrant pain (90%), and jaundice (80%).
Normal lipase and amylase.
Blood cultures are usually positive, especially during episodes of chills, with Escherichia coli and Klebsiella as the most common micro-organisms isolated from infected bile.[22]
Choledocholithiasis
SIGNS / SYMPTOMS
Severe right upper quadrant pain of sudden onset, jaundice, acholia, choluria, and history of cholelithiasis. May occlude the common bile duct and cause pancreatitis.
INVESTIGATIONS
Normal or slightly elevated lipase and amylase.
Ultrasound will show gallstones, stones within the common bile duct with extra-hepatic and/or intra-hepatic duct dilatation.
Chemistry will show biochemical obstruction, with increased levels of total and direct bilirubin, alkaline phosphatase, gamma glutamyl transpeptidase, and a slight increase in alanine aminotransferase/aspartate aminotransferase but normal levels of pancreatic enzymes (especially lipase).
Cholecystitis
SIGNS / SYMPTOMS
Pain is generally triggered after a fatty meal and localised in the right upper quadrant. More common in overweight females between 40 and 50 years of age.
Anorexia, nausea, and vomiting may be present. May show a positive Murphy's sign and low-grade fever.
INVESTIGATIONS
Normal or slightly elevated lipase and amylase.
A right upper quadrant ultrasound will show thickened gallbladder wall, stones with acoustic shadows, biliary sludge, peri-cholecystic fluid, and sonographic Murphy's sign, and allows evaluation of the duct system. Can suggest pancreatic head inflammation. May show mild leukocytosis and a very mild elevation of liver enzymes.
A hepatobiliary iminodiacetic acid scan is diagnostic when there is no filling of the gallbladder or with delayed emptying of the radiotracer.
Viral gastroenteritis
SIGNS / SYMPTOMS
Generalised non-specific abdominal pain, anorexia, nausea, emesis, diarrhoea, and dehydration.
Is usually a self-limiting viral infection but if fever is documented, bacterial and invasive organisms should be suspected.
Consider in travellers and immunosuppressed patients.
Consider osmotic and secretory diarrhoea from history.
INVESTIGATIONS
Normal or slightly elevated lipase and amylase.
Important to obtain serum electrolytes and an FBC.
Hypokalaemia and alkalosis may be seen secondary to diarrhoea, vomiting, and dehydration.
Stool examination for microscopy, culture, osmolality, ova, parasites, Clostridium difficile toxin, and white blood cells may help in identifying the causative factor.
Hepatitis
SIGNS / SYMPTOMS
Jaundice, right upper quadrant pain, anorexia, and general malaise. Choluria and acholia may be seen.
Examination: tenderness to palpation over the right upper quadrant and enlarged liver.
INVESTIGATIONS
Normal lipase and amylase.
Elevated liver function tests are characteristic. Aspartate aminotransferase/alanine aminotransferase in the range of the 1000 units/L is not rare. Serological titres can make diagnosis of aetiological cause.
Radiographic studies not important for its diagnosis.
Mesenteric ischaemia
SIGNS / SYMPTOMS
Patients are usually older, may have a history of atrial fibrillation and risk factors for peripheral vascular disease.
Hypercoagulable states may lead to bowel necrosis. Pain is usually out of proportion to the finding of the physical examination.
INVESTIGATIONS
High index of suspicion of diagnosis is necessary. Angiography and CT scan may be useful in diagnosis as well as lactic acid levels.
Normal lipase. May have elevated amylase (usually less marked than that seen in acute pancreatitis).
Myocardial infarction
SIGNS / SYMPTOMS
Pain is usually retrosternal with radiation to jaw, neck, and left upper extremity. Associated with shortness of breath, nausea, vomiting, and diaphoresis. Cardiovascular risk factors in the history.
INVESTIGATIONS
Elevated cardiac enzymes (creatine kinase or creatine phosphokinase, troponins), ECG changes, and clinical scenario make the diagnosis.
Normal lipase and amylase.
Cardiac catheterisation, perfusion scans, and echocardiograms are useful during the work-up of cardiac ischaemia.
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