What is the most likely diagnosis and appropriate emergency management for a patient with epigastric pain, three episodes of vomiting, obstipation for three days (but passed flatus three times yesterday), hyperactive bowel sounds and no abdominal rigidity?

Most Likely Diagnosis and Emergency Management

This clinical presentation most strongly suggests partial small bowel obstruction or early large bowel obstruction, and requires immediate CT abdomen/pelvis with IV contrast to exclude surgical emergencies including complete obstruction, closed-loop obstruction, or bowel ischemia. 1

Immediate Assessment and Risk Stratification

Check vital signs immediately for tachycardia ≥110 bpm, fever ≥38°C, or hypotension, which predict perforation, anastomotic leak, or sepsis with high specificity. 2, 3 The absence of abdominal rigidity argues against perforation, but does not exclude it entirely. 1, 3

Obtain an ECG within 10 minutes to exclude myocardial infarction, which presents atypically with epigastric pain as the primary manifestation in women, diabetics, and elderly patients, with mortality rates of 10-20% if missed. 2, 3 Never rely on a single troponin measurement—obtain serial troponins at 0 and 6 hours. 2, 3

The ability to pass flatus three times yesterday indicates the obstruction is partial rather than complete, but this does not exclude the need for urgent intervention. 1 In large bowel obstruction, absence of passage of flatus occurs in 90% and absence of feces in 80.6%, making the recent flatus passage clinically significant. 1

Clinical Reasoning for Bowel Obstruction

Hyperactive bowel sounds with obstipation for three days strongly suggests mechanical bowel obstruction. 1 In large bowel obstruction, abdominal examination shows tenderness, abdominal distension, and hyperactive or absent bowel sounds. 1 The progression from hyperactive to absent bowel sounds indicates worsening obstruction or development of ileus. 1

The combination of epigastric pain, vomiting, and obstipation creates a high-risk scenario that mandates urgent imaging regardless of the ability to pass flatus. 1, 4 Vomiting is less frequent in large bowel obstruction than small bowel obstruction, but three episodes of vomiting with obstipation raises concern for either proximal large bowel or distal small bowel obstruction. 1

Mandatory Emergency Investigations

Order immediately:

• CT abdomen and pelvis with IV contrast is the gold standard with diagnostic accuracy >90% for bowel obstruction, identifying the site, cause, and presence of complications such as ischemia, closed-loop obstruction, or perforation. 1, 2
• Complete blood count to assess for leukocytosis suggesting ischemia or perforation. 1
• Serum lactate and metabolic panel to evaluate for lactic acidosis (suggesting necrosis), electrolyte imbalances, and elevated urea nitrogen from dehydration. 1, 2
• Serum amylase (≥4x normal) or lipase (≥2x normal) to exclude acute pancreatitis, which has 80-90% sensitivity and specificity. 2, 3

Do not administer oral contrast for suspected high-grade obstruction because the nonopacified fluid in the bowel provides adequate intrinsic contrast, and oral contrast may worsen obstruction. 1

CT Findings That Mandate Immediate Surgery

Specific imaging signs suggesting bowel ischemia that warrant immediate surgical consultation include: 1

• Abnormally decreased or increased bowel wall enhancement
• Intramural hyperdensity on noncontrast CT
• Bowel wall thickening
• Mesenteric edema
• Ascites
• Pneumatosis or mesenteric venous gas

Closed-loop obstruction, volvulus, or complete obstruction identified on CT require urgent surgical intervention. 1

Initial Management Algorithm

Step 1: Maintain NPO status until surgical emergency is excluded. 3

Step 2: Establish IV access and begin fluid resuscitation to correct physiologic and electrolyte disturbances from vomiting and dehydration. 1, 5

Step 3: Obtain immediate surgical consultation given the combination of epigastric tenderness, vomiting, and obstipation. 3 Do not delay surgical consultation while awaiting imaging if the patient develops peritoneal signs or hemodynamic instability. 1, 3

Step 4: Hospital admission for observation and serial examinations is mandatory regardless of imaging findings. 3

Step 5: If imaging reveals partial obstruction without ischemia, conservative management includes: 1, 5

• Bowel rest (NPO)
• Nasogastric tube decompression if vomiting persists
• IV fluid resuscitation
• Serial abdominal examinations every 4-6 hours
• Repeat imaging if clinical deterioration occurs

Critical Pitfalls to Avoid

Never dismiss this presentation as functional dyspepsia or gastroenteritis. Persistent vomiting with obstipation is a red flag that excludes functional disease and mandates investigation for structural pathology. 1, 6

Do not delay imaging based on the ability to pass flatus. Recent flatus passage indicates partial obstruction, which can progress to complete obstruction or develop ischemia. 1

Avoid administering NSAIDs for pain control as they worsen peptic ulcer disease and bleeding risk if that is the underlying cause. 2, 3

Do not assume the absence of abdominal rigidity excludes perforation. Perforated peptic ulcer can present with localized tenderness before developing diffuse peritonitis, and mortality reaches 30% if treatment is delayed. 2, 3

Colicky abdominal pain persisting more than 4 hours mandates urgent investigation with CT. 7 Emergency care providers should seek expert surgical advice early rather than pursuing prolonged observation. 7

Alternative Diagnoses to Exclude

While bowel obstruction is most likely, also consider:

• Perforated peptic ulcer if pain becomes suddenly severe and generalized, though the absence of rigidity makes this less likely. 2, 3
• Acute pancreatitis if pain radiates to the back, diagnosed by elevated amylase/lipase. 2, 3
• Boerhaave's syndrome (esophageal rupture) after excessive vomiting, which has high mortality if untreated. 8