What is the differential diagnosis and initial management for a patient with epigastric pain radiating to the shoulder?

Differential Diagnosis for Epigastric Pain Radiating to Shoulder

Epigastric pain radiating to the shoulder demands immediate consideration of life-threatening conditions first—specifically myocardial infarction, acute aortic syndromes, and ruptured viscus—before evaluating gastrointestinal causes. 1

Critical Life-Threatening Diagnoses (Rule Out First)

Cardiovascular Causes

• Myocardial infarction/Acute Coronary Syndrome: Epigastric pain can be the primary presentation of cardiac ischemia, particularly in women, diabetics, and elderly patients who may present atypically 1
• Acute aortic dissection: Can present with severe epigastric pain and requires emergent imaging 1
• Obtain immediate ECG and cardiac biomarkers (troponin at presentation and 6 hours later) for any patient with epigastric pain and shoulder radiation 1

Intra-abdominal Emergencies

• Perforated peptic ulcer: Free air under diaphragm irritates phrenic nerve causing referred shoulder pain; mortality up to 30% if untreated 1
• Ruptured ovarian cyst with hemoperitoneum: Can present with epigastric pain radiating to right shoulder tip from diaphragmatic irritation 2
• Splenic rupture or subcapsular hematoma: Left shoulder pain (Kehr's sign) from diaphragmatic irritation

Common Gastrointestinal Causes

Upper GI Pathology

• Peptic ulcer disease (PUD): Incidence 0.1-0.3%; complications occur in 2-10% of cases 1
  • Duodenal ulcers: Pain 2-3 hours after eating, relieved by food 3
  • Gastric ulcers: Pain immediately after eating, worsened by food, may radiate to back 3
• Gastroesophageal reflux disease (GERD): Affects 42% of Americans monthly; presents with heartburn, regurgitation, and epigastric pain 1
• Acute gastritis: Often associated with NSAID use, alcohol, or H. pylori infection 1
• Gastric cancer: Consider in patients with alarm symptoms (weight loss, dysphagia, hematemesis) 1

Hepatobiliary and Pancreatic

• Acute cholecystitis/biliary colic: Right upper quadrant pain radiating to right shoulder via phrenic nerve irritation 4
• Acute pancreatitis: Classic presentation includes epigastric pain radiating to the back 1, 3
• Hepatic pathology: Hepatitis, hepatic abscess, or hepatic congestion can cause referred shoulder pain

Initial Management Algorithm

Step 1: Immediate Assessment (Within Minutes)

• Vital signs: Hypotension, tachycardia suggest hemorrhage or shock 1
• ECG: Obtain within 10 minutes of presentation for any epigastric pain 1
• Cardiac biomarkers: Troponin at 0 and 6 hours to rule out NSTEMI 1
• Complete blood count: Acute hemoglobin drop suggests active bleeding 2

Step 2: Risk Stratification

High-risk features requiring immediate intervention:

• Hemodynamic instability
• ST-segment changes on ECG
• Acute hemoglobin drop >2 g/dL
• Peritoneal signs on examination
• Age >50 with new-onset symptoms 1

Step 3: Imaging Strategy

• Upright chest X-ray: First-line to detect free air under diaphragm (perforation) 4
• Bedside ultrasound: Rapid assessment for free fluid, gallbladder pathology, aortic aneurysm 4
• CT abdomen/pelvis with IV contrast: Gold standard for acute abdomen when diagnosis unclear; can identify pancreatitis, perforation, vascular emergencies 1
• Upper endoscopy: Definitive test for PUD, gastritis, esophagitis when patient is stable 1

Step 4: Empiric Management While Awaiting Diagnosis

• NPO status until surgical emergency excluded
• IV access and fluid resuscitation if hemodynamically unstable
• Proton pump inhibitor therapy: Omeprazole 20 mg for suspected acid-related pathology 1
• Avoid NSAIDs: Can worsen PUD and bleeding risk 1

Critical Pitfalls to Avoid

• Do not dismiss cardiac causes in patients presenting with "atypical" epigastric pain—women, diabetics, and elderly frequently present without classic chest pain 1
• Do not delay imaging in patients with peritoneal signs; perforated ulcer mortality increases significantly with delayed diagnosis 1
• Do not rely on single troponin: Requires serial measurements at least 6 hours apart to exclude NSTEMI 1
• Do not assume GERD without excluding life-threatening causes first, even in patients with known reflux disease 1
• Consider gynecologic emergencies in women of reproductive age—ruptured ovarian cysts can present identically to GI pathology 2