What is the initial evaluation and management for a patient with consistent left upper quadrant (LUQ) pain?

Initial Evaluation and Management of Left Upper Quadrant (LUQ) Pain

CT abdomen and pelvis with IV contrast is the first-line imaging modality for patients presenting with consistent left upper quadrant pain, as it provides superior diagnostic accuracy for detecting the wide range of pathologies that can cause LUQ pain. 1

Initial Laboratory Workup

Order the following tests for all patients with acute LUQ pain:

• Complete blood count (CBC) to assess for leukocytosis indicating infection or inflammation (splenic abscess, pancreatitis) 2
• Comprehensive metabolic panel including liver function tests (ALT, AST, alkaline phosphatase, GGT, bilirubin) to evaluate hepatobiliary disease 2
• Pancreatic enzymes (amylase and lipase) to rule out pancreatitis, a common cause of LUQ pain 2
• Pregnancy test for all women of reproductive age to exclude ectopic pregnancy or pregnancy-related conditions 2

Additional Laboratory Tests Based on Clinical Suspicion

• Coagulation studies (PT/INR, PTT) if splenic rupture or hematoma is suspected 2
• Lactate level if mesenteric ischemia or severe infection is suspected 2
• Urinalysis to evaluate for renal stones or infection 2

Important caveat: Normal laboratory values do not exclude serious pathology; imaging studies are still necessary based on clinical presentation. 2

Imaging Strategy

First-Line Imaging: CT Abdomen and Pelvis with IV Contrast

CT with IV contrast is the gold standard because it:

• Changes the leading diagnosis in up to 51% of patients and alters management in 25% of cases with abdominal pain 1
• Provides superior detection of bowel wall pathology, pericolic abnormalities, vascular pathology, and intraabdominal fluid collections 1
• Has moderate sensitivity (69%) but excellent specificity (100%) for acute LUQ pathology 3

Alternative Imaging Modalities in Specific Scenarios

Use ultrasound as initial imaging when:

• Patient is pregnant or young (radiation exposure concern) 1
• Premenopausal woman with suspected gynecologic pathology 1
• Suspected gallbladder pathology with referred LUQ pain (81% sensitivity, 83% specificity for acute cholecystitis) 1

Use unenhanced CT when:

• IV contrast is contraindicated 1
• Suspected urolithiasis (sensitivity and specificity near 100%) 1
• Patient is elderly (≥75 years), as unenhanced CT has similar accuracy to contrast-enhanced CT 1

Imaging Modalities to Avoid

• Plain radiography has limited utility due to low sensitivity, though it may detect pneumoperitoneum or bowel obstruction 1
• MRI is not recommended initially due to longer acquisition time, less sensitivity for extraluminal air, motion artifacts in symptomatic patients, and screening requirements for contraindications 4, 1
• Fluoroscopic contrast enema is not recommended as initial imaging 1

Common Pathologies to Consider in LUQ Pain

Pancreatic Pathology

• Acute pancreatitis requires contrast-enhanced CT for severity assessment and detection of complications 1
• Elevated amylase and lipase strongly suggest pancreatitis 2

Splenic Pathology

• Splenic infarction, abscess, or rupture 2
• Splenic torsion can present with LUQ pain and may show characteristic "upside down spleen" sign on coronal CT reconstruction 5

Renal Pathology

• Pyelonephritis and nephrolithiasis can be evaluated with high diagnostic accuracy on CT 1

Intestinal Pathology

• Colitis or diverticulitis extending to the LUQ 1

Atypical Presentations

• Left-sided appendicitis due to intestinal malrotation should be considered in the differential, especially in younger patients 6
• Coronary artery disease can present with LUQ pain, particularly in patients with spinal cord injury or other atypical risk factors 7

Common Pitfalls to Avoid

• Failing to order pregnancy test in women of reproductive age, potentially missing ectopic pregnancy 2
• Relying solely on plain radiographs which have poor sensitivity for most causes of LUQ pain 1
• Failing to use contrast enhancement when evaluating for vascular pathologies or abscesses 1
• Delaying appropriate imaging in elderly patients who may present with atypical symptoms and normal laboratory values 1
• Relying solely on laboratory tests without appropriate imaging studies when clinically indicated 2

Clinical Pearls

• Elevated white blood cell count with left shift suggests infection or inflammation (splenic abscess, pancreatitis, or diverticulitis) 2
• Elevated liver enzymes with cholestatic pattern may indicate biliary pathology extending to LUQ 2
• Consider patient's age, sex, and clinical presentation when selecting imaging modality 1
• Maintain high index of suspicion for cardiac pathology in patients with persistent "atypical" abdominal symptoms, especially when no specific abdominal organ dysfunction is evident 7