Evaluation of Upper Left Abdominal Pain
For acute upper left abdominal pain, obtain CT abdomen/pelvis with IV contrast as the primary imaging modality after initial laboratory workup including CBC, liver enzymes, amylase/lipase, and pregnancy test in women of reproductive age. 1, 2
Initial Laboratory Assessment
Obtain the following tests immediately for all patients:
- Complete blood count to identify leukocytosis suggesting infection, inflammation, or splenic pathology 2
- Comprehensive metabolic panel including liver enzymes (ALT, AST, alkaline phosphatase, bilirubin) to evaluate hepatobiliary disease 2
- Amylase and lipase to rule out pancreatitis, a common cause of left upper quadrant pain 2
- Pregnancy test for all women of reproductive age to exclude ectopic pregnancy 2
- Lactate level if severe pain out of proportion to examination findings raises concern for mesenteric ischemia 1, 2
Critical Clinical Red Flags
Suspect acute mesenteric ischemia when severe abdominal pain is out of proportion to physical examination findings—this requires immediate CT angiography 1. This presentation, particularly with acidosis and organ failure, represents a surgical emergency with high mortality 1.
Consider splenic pathology (rupture, infarct, abscess) if coagulation abnormalities or trauma history present; obtain coagulation studies (PT/INR, PTT) 2.
Imaging Strategy
CT abdomen/pelvis with IV contrast is the preferred initial imaging study 1:
- Sensitivity of 89% for urgent abdominal conditions 3
- Identifies pathology across multiple organ systems (spleen, pancreas, stomach, kidney, colon) 1
- Detects complications including perforation, abscess, and vascular occlusion 1
- Changes management in 51% of patients and admission decisions in 25% 1
Plain radiography has limited utility (49% sensitivity for bowel obstruction) but may identify pneumoperitoneum if perforation suspected 3. Skip this and proceed directly to CT in most cases 1.
CT angiography should be performed immediately if mesenteric ischemia suspected based on pain severity, lactate elevation, or vasopressor requirement 1.
Differential Diagnosis by Pathology
The left upper quadrant contains multiple organs requiring consideration:
- Splenic: infarction, rupture, abscess (elevated WBC with left shift suggests infection) 2
- Pancreatic: pancreatitis (elevated lipase >3x normal is diagnostic) 2
- Gastric: perforation, gastritis (look for pneumoperitoneum on imaging) 3
- Renal: pyelonephritis, nephrolithiasis (obtain urinalysis) 2
- Colonic: splenic flexure diverticulitis (though more commonly left lower quadrant) 1
- Cardiac: myocardial infarction can present as upper abdominal pain 4
Common Pitfalls to Avoid
Do not rely solely on laboratory values—normal labs do not exclude serious pathology; imaging remains necessary based on clinical presentation 2.
Do not miss mesenteric ischemia—this diagnosis requires high clinical suspicion in elderly patients, those with atrial fibrillation, or critically ill patients on vasopressors 1. The classic presentation of severe pain with minimal examination findings should trigger immediate CTA 1.
Do not forget pregnancy testing—failure to test women of reproductive age risks missing ectopic pregnancy 2.
Consider abdominal wall pain if pain worsens with muscle tensing (positive Carnett's sign), particularly in chronic presentations 5.
Special Populations
Elderly patients may present with atypical symptoms and normal laboratory values despite serious infection 1, 4. Maintain lower threshold for advanced imaging 1.
Neutropenic patients mask typical signs of sepsis, leading to delayed diagnosis and high mortality 1. Image early and liberally 1.
Postoperative patients with fever require cross-sectional imaging to evaluate for abscess, anastomotic leak, or hemorrhage 1.