Left Upper Quadrant Pain Differential Diagnosis
Left upper quadrant (LUQ) pain may arise from abdominal viscera or from thoracic disease with referred pain. LUQ pain is commonly referred from peptic ulcer disease, gastritis, esophagitis, pancreatitis, renal colic, cardiac angina, or pericarditis. [1]
Anatomic Sources Within the LUQ
The LUQ contains the spleen, stomach, bowel, pancreas, left lobe of the liver, left kidney, and left adrenal gland. [1]
Common Abdominal Etiologies
- Gastritis and gastric ulcer (including focal ulceration with or without perforation) [2]
- Splenic infarction (often due to emboli) [2]
- Splenic abscess (often due to hematogenous dissemination in immunocompromised individuals or intravenous drug abusers) [2]
- Splenic rupture in the setting of splenomegaly due to hematologic malignancy or viral infection (e.g., mononucleosis) [2]
- Pancreatitis [1]
- Colonic causes at the splenic flexure, including colitis [1]
Thoracic, Cardiac, and Serosal Etiologies
- Pneumonia with pleuritic pain that can present as referred LUQ pain [1]
- Pericarditis that can present as referred LUQ pain [1]
- Cardiac ischemia (cardiac angina) that can present as referred LUQ pain [1]
Urinary and Renal Etiologies
- Nephrolithiasis presenting with LUQ pain [3]
- Renal colic presenting as referred LUQ pain [1]
Initial Risk-Directed Diagnostic Priorities
- LUQ pain with fever requires urgent diagnostic workup because it raises concern for intraabdominal infection, abscess, or hematologic malignancy. [1]
- Splenomegaly increases the risk of splenic infarction, rupture, torsion, aneurysmal rupture, or venous thrombosis. [1]
Broad Differential Categories for Clinical Framing
- Gastrointestinal: peptic ulcer disease, gastritis, esophagitis, gastric ulcer/perforation, colitis, pancreatitis [1], [2]
- Splenic: infarction, abscess, rupture (often secondary to splenomegaly) [2], [1]
- Renal: nephrolithiasis and renal colic [3], [1]
- Cardiac/serosal: cardiac angina and pericarditis [1], [3]
- Thoracic: pneumonia causing pleuritic referred pain [1], [3]
Imaging-Driven Differential Sorting
CT is commonly used when LUQ pain diagnosis is uncertain. [3]
Common Emergency-Department Discharge Patterns After Nondiagnostic Imaging
In a consecutive emergency department cohort with LUQ pain, CT was nondiagnostic in 73% of cases. [3] The most common discharge diagnoses after nonspecific abdominal pain were urolithiasis (5%) and gastritis/gastric ulcer (5%). [3]