What is the next step in managing a patient with sudden severe persistent epigastric (upper abdominal) pain, nausea, vomiting, and leukocytosis (elevated white blood cell count), with normal amylase and lipase levels?

CT Scan of Abdomen and Pelvis

The next step is CT scan of the abdomen and pelvis with IV contrast (option c), as this patient presents with an acute abdomen requiring urgent evaluation for life-threatening conditions including perforated peptic ulcer, mesenteric ischemia, and other surgical emergencies that cannot be adequately excluded by other modalities. 1

Clinical Reasoning

This patient's presentation—sudden severe persistent epigastric pain with nausea, vomiting, and leukocytosis—represents an acute abdomen that demands immediate diagnostic imaging to identify potentially fatal conditions:

Why CT is the Priority

• CT scan is the recommended first-line imaging for suspected perforated peptic ulcer, which classically presents with sudden severe epigastric pain. The World Society of Emergency Surgery strongly recommends CT imaging in patients with acute abdomen from suspected perforated peptic ulcer, as it has superior sensitivity for detecting free air, characterizing perforation site and size, and excluding other causes. 1

• Normal amylase/lipase does NOT exclude serious pathology. While these enzymes are often elevated in pancreatitis, they are non-specific in acute mesenteric ischemia and perforated ulcer. In fact, elevated amylase occurs in only about half of patients with acute mesenteric ischemia, and isolated lipase elevation without amylase elevation should not be equated with pancreatitis. 1, 2

• Leukocytosis (11,000) with severe pain suggests significant intra-abdominal pathology. Laboratory findings in both perforated peptic ulcer and mesenteric ischemia are non-specific early in the disease course, but leukocytosis is commonly present. The combination of leukocytosis with severe abdominal pain warrants urgent CT evaluation. 1

Critical Differential Diagnoses Requiring CT

Perforated Peptic Ulcer:

• CT detects pneumoperitoneum, unexplained intraperitoneal fluid, bowel wall thickening, and mesenteric fat streaking with high sensitivity 1
• Up to 12% of perforations may have normal CT, but it remains the most sensitive test available 1
• Physical examination findings may be equivocal, and peritonitis may be minimal or absent in contained perforations 1

Acute Mesenteric Ischemia:

• Patients present with "abdominal pain out of proportion to physical examination"—a hallmark that fits this clinical scenario 1
• CT angiography should be performed as soon as possible for any patient with suspicion for acute mesenteric ischemia, as delay in diagnosis accounts for mortality rates of 30-70% 1
• Early laboratory findings (including normal amylase/lipase) are insufficient for diagnosis 1

Why Other Options Are Inadequate

IV Ranitidine (option a): Empiric acid suppression without diagnosis is inappropriate when life-threatening surgical emergencies must be excluded first. Treatment cannot precede diagnosis in this acute setting. 1

Urgent Endoscopy (option b): While endoscopy has a role in upper GI bleeding, it does not evaluate for perforation, mesenteric ischemia, or other extra-luminal pathology. CT must come first to assess for perforation and other surgical emergencies. 1

Abdominal Ultrasound (option d): Ultrasound has limited sensitivity for detecting free air from perforation and cannot adequately evaluate mesenteric vasculature or characterize the full extent of intra-abdominal pathology in acute abdomen. Plain radiographs and ultrasound are often insufficiently sensitive and specific for definitive diagnosis in acute abdomen presentations. 1

Key Clinical Pitfalls

• Do not rely on normal amylase/lipase to exclude surgical emergencies. These values are non-specific and frequently normal in perforated ulcer and early mesenteric ischemia. 1, 2

• Do not delay CT for plain radiography first. While some guidelines mention X-ray when CT is not promptly available, in facilities with CT access, proceeding directly to CT is appropriate given the superior diagnostic accuracy and the need to exclude multiple life-threatening conditions simultaneously. 1

• Recognize that "sudden severe persistent" pain suggests a catastrophic event (perforation, vascular occlusion, or other surgical emergency) rather than medical conditions amenable to empiric therapy. 1