What are the causes and treatment options for left upper quadrant abdominal pain?

Left Upper Quadrant Abdominal Pain: Causes and Management

Initial Imaging Recommendation

CT of the abdomen and pelvis with IV contrast is the first-line imaging modality for evaluating left upper quadrant (LUQ) pain when the diagnosis is unclear. 1

This recommendation is based on CT's superior diagnostic accuracy, ability to detect a wide range of pathologies, and capacity to change the leading diagnosis in up to 51% of patients and management decisions in 25% of cases. 1

Common Causes of LUQ Pain

Gastrointestinal Pathology

• Acute pancreatitis is a primary consideration requiring contrast-enhanced CT for severity assessment and detection of complications 1
• Gastric pathology including gastritis or peptic ulcer disease can be evaluated with CT 2
• Splenic pathology such as splenomegaly, infarction, or abscess is well-visualized on contrast-enhanced CT 2
• Colonic pathology including diverticulitis or colitis extending to the LUQ can be identified on CT 1

Renal and Urologic Causes

• Pyelonephritis and nephrolithiasis are common LUQ pain etiologies that CT evaluates with high diagnostic accuracy 1
• For suspected urolithiasis specifically, unenhanced CT has sensitivity and specificity near 100% 1

Atypical Presentations Requiring High Clinical Suspicion

• Appendicitis with intestinal malrotation can present as LUQ pain rather than the typical right lower quadrant location 3, 4
• Mobile cecum may result in appendicitis presenting with LUQ pain 4
• These atypical presentations underscore why CT is essential when the diagnosis is uncertain 3

Diagnostic Algorithm

Step 1: Clinical Assessment

• Evaluate for fever, leukocytosis, and specific pain characteristics 2
• Consider age, sex, and relevant medical history when selecting imaging 1
• In premenopausal women, consider gynecologic causes and start with pelvic ultrasound if clinically suspected 1

Step 2: Initial Imaging Selection

• Standard approach: CT abdomen/pelvis with IV contrast 1
• If contrast contraindicated: Unenhanced CT (particularly effective in elderly patients ≥75 years) 1
• Pregnant or young patients: Ultrasound as initial modality to avoid radiation 1
• Suspected gallbladder pathology with referred pain: Ultrasound (81% sensitivity, 83% specificity for acute cholecystitis) 1

Step 3: Interpret CT Findings

CT in the emergency setting for LUQ pain demonstrates moderate sensitivity (69%) but excellent specificity (100%) and positive predictive value (100%). 5 This means:

• A positive CT finding reliably identifies the cause of pain 5
• A negative CT does not completely exclude pathology, as 12% of patients with negative CT may have clinically detectable pathology 5

Imaging Modalities to Avoid

Do not use these as initial studies for acute LUQ pain:

• Plain radiography has limited utility due to low sensitivity, though it may detect pneumoperitoneum or bowel obstruction 1
• Fluoroscopic contrast enema is not appropriate for initial LUQ pain evaluation 1
• MRI is not recommended initially due to longer acquisition time, reduced sensitivity for extraluminal air, motion artifacts in symptomatic patients, and screening requirements for contraindications 1

Treatment Approach Based on Diagnosis

If Specific Pathology Identified on CT

• Pancreatitis: Manage according to severity with supportive care, NPO status, fluid resuscitation 2
• Splenic pathology: Treat based on specific diagnosis (observation vs. intervention) 2
• Diverticulitis: Medical management for uncomplicated cases; consider drainage for abscesses ≥3 cm; surgery for perforation 6
• Atypical appendicitis: Surgical management (laparoscopic appendectomy, potentially with Ladd's procedure if malrotation present) 3

If Pain Associated with Eating

• Consider mesenteric ischemia in appropriate clinical context and pursue vascular imaging 2

If Fatty Liver Incidentally Detected

• Important caveat: Fatty liver typically does not cause LUQ pain; the pain requires separate evaluation 2
• If fatty liver is found, perform complete evaluation for NAFLD including assessment of metabolic risk factors, alcohol consumption history, and exclusion of other causes 2
• Monitor liver enzymes every 3-6 months with follow-up imaging 2

Critical Pitfalls to Avoid

• Do not rely solely on plain radiographs, which have poor sensitivity for most LUQ pain causes 1
• Do not fail to use contrast enhancement when evaluating for vascular pathologies or abscesses 1
• Do not delay imaging in elderly patients who may present with atypical symptoms and normal laboratory values 1
• Do not dismiss the possibility of appendicitis in patients with LUQ pain, especially if intestinal malrotation or mobile cecum is present 3, 4
• Do not assume negative CT completely excludes pathology; maintain clinical suspicion and consider follow-up if symptoms persist 5

Follow-Up Recommendations

• If CT identifies specific pathology: Follow-up based on the identified cause and treatment response 2
• If CT negative but symptoms persist: Consider repeat imaging or specialist consultation, as 12% of patients with negative CT may have undetectable pathology 5
• If incidental findings noted: Address appropriately with targeted follow-up imaging or specialist referral 2