What are the possible causes and treatments for left upper quadrant abdominal pain?

Left Upper Quadrant Abdominal Pain: Diagnostic and Management Approach

Immediate Imaging Strategy

CT abdomen and pelvis with IV contrast is the preferred initial imaging modality for evaluating left upper quadrant pain, providing comprehensive assessment with excellent diagnostic accuracy. 1

• The American College of Radiology rates CT with IV contrast as 8/9 (usually appropriate) for this clinical scenario, as it evaluates all potential causes including splenic pathology, pancreatic disease, gastric abnormalities, and vascular conditions 1
• CT alters the initial diagnosis in approximately 51% of patients with nonlocalized abdominal pain and changes admission decisions in 25% of cases 2
• Plain radiography has very limited diagnostic value and should not be used for left upper quadrant pain evaluation 1
• Ultrasound has limited utility in this anatomic location due to overlying bowel gas and rib shadowing, though it may identify splenic or renal pathology 1

Critical Clinical Features to Assess

Identify fever and leukocytosis immediately, as these indicate inflammatory or infectious processes requiring urgent imaging and intervention. 1

• Fever with left upper quadrant pain raises suspicion for intra-abdominal abscess, splenic abscess, pyelonephritis, or perforated viscus 2, 1
• The combination of fever, abdominal pain, and leukocytosis constitutes a high-risk presentation requiring immediate CT evaluation 2
• In elderly or immunocompromised patients, typical signs of infection may be masked and laboratory values may be falsely reassuring despite serious pathology 2

Differential Diagnosis by Organ System

Splenic Pathology

• Splenic infarction, abscess, or rupture (traumatic or spontaneous) 1
• CT with IV contrast provides definitive diagnosis 1

Pancreatic Disease

• Acute pancreatitis (check lipase level) 3
• Pancreatic mass with secondary complications 2

Gastric Abnormalities

• Gastric perforation or ulcer 1
• Gastric outlet obstruction 1

Renal/Urologic Causes

• Nephrolithiasis or pyelonephritis should be excluded in cases without fever 1
• Urinalysis is essential in the initial workup 3

Vascular Emergencies

• Splenic artery aneurysm or dissection 1
• Mesenteric ischemia (consider if postprandial pain with weight loss and atherosclerotic risk factors) 1

Atypical Presentations

• Malrotation with atypical appendicitis can present as left upper quadrant pain and must not be missed 1, 4
• Internal hernias with incarcerated bowel 5
• Mobile cecum with appendicitis 6

Management Algorithm Based on CT Findings

If Intra-abdominal Abscess Identified

• Source control with percutaneous drainage for abscesses ≥3-4 cm 1
• Broad-spectrum antibiotics immediately after blood cultures if sepsis suspected 1
• Surgical consultation if drainage not feasible or patient deteriorating 1

If Perforation Detected (Free Intraperitoneal Air)

• Immediate surgical consultation required 1
• NPO status, IV fluid resuscitation, nasogastric decompression 1
• Broad-spectrum antibiotics 1

If Renal Pathology Confirmed

• Nephrolithiasis: analgesia, hydration, urology referral for stones >5mm 1
• Pyelonephritis: antibiotics based on local resistance patterns 1

If Negative CT with Persistent Symptoms

• Consider functional dyspepsia if postprandial pain predominates 1
• Test for H. pylori and treat if positive 1
• Trial of proton pump inhibitors or H2-receptor antagonists 1
• Tricyclic antidepressants as second-line for refractory symptoms 1

Common Pitfalls to Avoid

Do not dismiss left upper quadrant pain as benign without imaging when clinical suspicion exists, as CT identifies unexpected findings including malrotation with atypical appendicitis in rare cases. 1, 4

• Clinical diagnosis alone has poor accuracy for left upper quadrant pathology, with CT detecting acute abnormalities in 39% of patients presenting to emergency departments 7
• CT has 100% positive predictive value when abnormalities are detected and 100% specificity for ruling out acute pathology 7
• Sensitivity is moderate at 69%, meaning some pathologies may be missed, but negative predictive value is 83% 7

Red Flags Requiring Emergency Evaluation

Immediate emergency department evaluation is mandatory for: 1

• Fever with severe abdominal tenderness, guarding, or rebound
• Inability to pass gas or stool with abdominal distension
• Signs of shock (hypotension, tachycardia, altered mental status)
• Bloody stools or hematemesis
• Progressively worsening pain over hours to days

Laboratory Testing Priority

Order the following tests before or concurrent with imaging: 3

• Complete blood count with differential
• C-reactive protein (CRP >50 mg/L increases diagnostic accuracy) 8
• Hepatobiliary markers (AST, ALT, alkaline phosphatase, bilirubin)
• Lipase (for pancreatic pathology)
• Urinalysis
• Pregnancy test in women of reproductive age