What is the appropriate immediate management for an adult patient with a history of abdominal issues presenting with intermittent severe abdominal pain, nausea, vomiting, abdominal distention, and an absence of flatus, suggestive of a possible bowel obstruction?

Immediate Management of Suspected Bowel Obstruction

This patient requires immediate resuscitation with IV fluids, nasogastric tube decompression, NPO status, and urgent CT abdomen/pelvis with IV contrast to differentiate mechanical obstruction from ileus and identify signs of bowel ischemia that would mandate emergency surgery. 1, 2, 3

Initial Resuscitation and Stabilization

Begin aggressive IV crystalloid resuscitation immediately upon presentation, as bowel obstruction causes third-spacing of fluids and significant dehydration. 4, 3 Insert a nasogastric tube for gastric decompression to prevent aspiration pneumonia and reduce vomiting—this is particularly critical given the patient's active vomiting. 4, 3 Place a Foley catheter to monitor urine output as a marker of adequate resuscitation. 4 Administer antiemetics for symptom control and maintain strict NPO status. 4, 5

Critical Diagnostic Workup

Order CT abdomen/pelvis with IV contrast immediately—this is the diagnostic standard with >90% accuracy and can identify life-threatening complications. 1, 2, 4 Do not give oral contrast in suspected high-grade obstruction, as the non-opacified fluid provides adequate intrinsic contrast. 2, 4 This imaging will determine:

• Presence and location of obstruction with identification of a transition point between dilated and collapsed bowel 6, 1
• Signs of bowel ischemia including abnormal bowel wall enhancement, mesenteric edema, pneumatosis, or portal venous gas—any of these findings mandate immediate surgery 2, 4
• Underlying etiology such as adhesions, hernias, masses, or volvulus 4

Plain abdominal X-rays have only 50-60% sensitivity and are non-diagnostic in 36% of cases—they should not delay CT imaging. 1, 4

Laboratory Assessment

Draw the following labs immediately:

• Complete blood count to assess for leukocytosis >10,000/mm³ suggesting peritonitis or ischemia 1, 4
• Lactate level as elevation indicates bowel ischemia and predicts need for surgery 1, 2, 4
• Electrolyte panel focusing on potassium, which is frequently low and requires correction before any surgical intervention 4
• Renal function tests (BUN/creatinine) to assess degree of dehydration 1, 4
• CRP as values >75 mg/L suggest peritonitis 4
• Coagulation profile given potential need for emergency surgery 4

Red Flags Requiring Emergency Surgery

Call surgery immediately if any of the following are present, as mortality increases from 10% to 25-30% with delayed intervention: 2, 4

• Fever, tachycardia ≥110 bpm, tachypnea, or confusion suggesting strangulation 2
• Intense pain unresponsive to analgesics indicating ischemia 2
• Diffuse tenderness with guarding or rebound signaling peritonitis 2
• Absent bowel sounds (note: the patient's lack of flatus is concerning, but absent sounds on exam indicate advanced ischemia) 1, 2
• Hypotension, cool extremities, mottled skin, oliguria representing shock 1, 2
• CT findings of ischemia including abnormal enhancement, pneumatosis, or mesenteric venous gas 2, 4

Clinical Context and Etiology

The presentation of intermittent severe colicky pain, vomiting, distention, and absence of flatus is classic for mechanical bowel obstruction. 6, 1, 3 Ask specifically about:

• Previous abdominal surgeries (85% sensitivity for adhesive small bowel obstruction, which accounts for 55-75% of cases) 6, 1, 4
• History of hernias (10-15% of cases) 4
• Previous diverticulitis or chronic constipation suggesting large bowel obstruction from diverticular disease or volvulus 6, 1
• Rectal bleeding or weight loss concerning for colorectal cancer (60% of large bowel obstructions) 6, 1
• Medication history, particularly opioids which can cause narcotic bowel syndrome mimicking mechanical obstruction 6, 4

Examine all hernia orifices and previous surgical incision sites, as incarcerated hernias require immediate surgical reduction. 1, 4

Management Algorithm Based on CT Findings

If CT shows signs of ischemia or complete obstruction with complications: Proceed directly to emergency laparotomy—do not delay. 2, 4

If CT shows partial obstruction without ischemia: Trial of conservative management with continued NG decompression, IV fluids, bowel rest, and serial abdominal exams every 4-6 hours. 2, 4, 3 Most partial small bowel obstructions resolve with conservative therapy. 4, 3

If CT shows complete obstruction without ischemia: Early surgical consultation is mandatory, as most will require operative intervention within 24-48 hours if no improvement. 2, 3

Critical Pitfalls to Avoid

Do not mistake incomplete obstruction with watery diarrhea for gastroenteritis—patients can have paradoxical diarrhea as liquid stool passes around a partial obstruction. 1, 4

Do not rely on hyperactive bowel sounds to rule out ischemia—when sounds transition from hyperactive to absent, this indicates progression to ischemia with mortality up to 25%. 1, 2

Do not delay surgical consultation when lactate is elevated or CT shows concerning features—every hour of delay with ischemic bowel increases mortality. 2, 4

In elderly patients, pain may be less prominent despite severe obstruction—maintain high suspicion even with minimal pain. 1, 4