What could be causing left upper quadrant abdominal pain accompanied by vomiting?

Left Upper Quadrant Pain with Vomiting: Diagnostic Approach

CT abdomen and pelvis with IV contrast is the preferred initial imaging modality for evaluating left upper quadrant pain with vomiting, as it provides comprehensive assessment of all potential causes with excellent diagnostic accuracy. 1

Immediate Clinical Assessment

The evaluation must focus on identifying red flag features that indicate life-threatening conditions requiring urgent intervention:

• Fever with leukocytosis suggests inflammatory or infectious processes (splenic abscess, pancreatitis, perforated viscus) requiring urgent imaging 1
• Rebound tenderness with abdominal distension occurs in 82.5% of patients with peritonitis and mandates immediate surgical evaluation 1
• Recent excessive vomiting should raise concern for Boerhaave's syndrome (spontaneous esophageal rupture), which has high mortality if untreated 2
• Postprandial pain pattern may suggest mesenteric ischemia (especially with weight loss and atherosclerotic risk factors) or functional dyspepsia 1

Key Differential Diagnoses

Life-Threatening Causes (Require Immediate Action)

• Splenic pathology (rupture, infarction, abscess) - CT detects with high sensitivity 1
• Acute pancreatitis - presents with upper abdominal pain and vomiting; diagnosis confirmed by serum amylase >4× normal or lipase >2× upper limit 3
• Perforated viscus - free intraperitoneal air on CT has 92% positive predictive value for perforation requiring surgical consultation 1
• Boerhaave's syndrome - spontaneous esophageal rupture after excessive vomiting; CT shows mediastinal air/fluid 2
• Intestinal obstruction - CT identifies level and cause; requires nasogastric decompression and surgical evaluation 1, 4

Important Atypical Presentations

• Malrotation with left upper quadrant appendicitis - CT can detect this rare but critical diagnosis that alters management in 49% of cases with nonlocalized pain 1, 5
• Internal hernia (e.g., through foramen of Winslow) - may present with acute left upper quadrant pain and requires exploratory surgery if suspected 6

Common Non-Emergent Causes

• Gastric pathology (gastritis, peptic ulcer disease) - consider H. pylori testing and acid suppression 1
• Renal pathology (nephrolithiasis, pyelonephritis) - should be excluded in cases without fever 1
• Functional dyspepsia - most common cause when structural abnormalities are excluded 1

Imaging Strategy

CT abdomen and pelvis with IV contrast is rated 8/9 (usually appropriate) by the American College of Radiology and should not be delayed when clinical suspicion exists, as it:

• Alters diagnosis in nearly half of cases 1
• Detects free intraperitoneal air with 92% positive predictive value for perforation 1
• Identifies splenic, pancreatic, gastric, and vascular pathology comprehensively 1
• Can detect unexpected findings like malrotation with atypical appendicitis 1, 5

Plain radiography has very limited diagnostic value and should not be used as the initial test 1

Ultrasound has limited utility in the left upper quadrant due to overlying bowel gas and rib shadowing, though it may identify splenic or renal pathology 1

Critical Laboratory Red Flags

Obtain urgent labs to assess for ischemia or perforation: 4

• Elevated lactate, low serum bicarbonate, or low arterial pH suggest intestinal ischemia 4
• Marked leukocytosis indicates possible perforation or necrosis 4
• Elevated amylase/lipase confirms pancreatitis (amylase >4× normal or lipase >2× upper limit) 3

Immediate Management Algorithm

If Peritonitis Signs Present (rebound tenderness, guarding, rigid abdomen):

1. Immediate surgical consultation 1, 4
2. Broad-spectrum antibiotics after blood cultures if sepsis suspected 1
3. NPO status, IV fluid resuscitation, nasogastric decompression 1, 4
4. Urgent CT with IV contrast to identify perforation or ischemia 1

If Excessive Vomiting Preceded Pain:

1. Consider Boerhaave's syndrome - obtain CT chest/abdomen to evaluate for esophageal rupture 2
2. Endoscopic stent placement is preferred over surgery in hemodynamically stable patients without sepsis diagnosed >24 hours after rupture 2

If Pancreatitis Suspected:

1. Serum amylase and lipase - diagnostic if amylase >4× normal or lipase >2× upper limit 3
2. Assess severity - overall mortality should be <10%, <30% in severe disease 3
3. Supportive care with IV fluids, pain control, antiemetics 3
4. Monitor for postembolization syndrome if recent procedure - presents with nausea, vomiting, upper quadrant pain, fever 3

If Stable Without Red Flags:

1. CT abdomen/pelvis with IV contrast as first-line imaging 1
2. Consider functional dyspepsia if imaging negative - test for H. pylori and treat if positive 1
3. Trial of proton pump inhibitors or H2-receptor antagonists for symptom relief 1

Common Pitfalls to Avoid

• Do not dismiss left upper quadrant pain as benign without imaging when clinical suspicion exists - CT alters diagnosis in 49% of cases 1
• Do not rely on plain radiography - it has very limited diagnostic value and may delay definitive diagnosis 1, 4
• Do not miss Boerhaave's syndrome - always consider in patients with upper abdominal pain after excessive vomiting 2
• Do not overlook atypical appendicitis - malrotation can cause left upper quadrant appendicitis requiring surgical intervention 1, 5
• Do not delay surgical consultation if peritonitis signs, systemic toxicity, or CT shows perforation/ischemia 1, 4