A 45-year-old man comes to the emergency department due to intermittent, crampy abdominal … — USMLE Step 2 CK

A 45-year-old man comes to the emergency department due to intermittent, crampy abdominal pain and nausea for the past 24 hours. He has vomited twice and has not passed flatus since yesterday. His surgical history is significant for an open appendectomy for a perforated appendix 10 years ago.

Vital signs include a temperature of $37.1^\circ\text{C}$ ( $98.8^\circ\text{F}$ ), pulse of $88/\text{min}$ , respirations of $14/\text{min}$ , and blood pressure of $130/82\text{ mm Hg}$ . The abdomen is moderately distended and tympanitic to percussion. High-pitched, hyperactive bowel sounds are auscultated. There is mild, diffuse abdominal tenderness to deep palpation, but no guarding, rigidity, or rebound tenderness is present.

Laboratory studies show a leukocyte count of $8,200/\text{mm}^3$ and a normal basic metabolic panel. A CT scan of the abdomen and pelvis with intravenous contrast reveals dilated loops of small bowel up to $4\text{ cm}$ in diameter, a transition point in the distal ileum, and a collapsed colon. The bowel wall enhances normally, and there is no evidence of pneumatosis intestinalis, free intraperitoneal air, or free fluid.

Which of the following is the most appropriate next step in management?

Placement of a nasogastric tube and intravenous fluidsAnswer
B
Immediate exploratory laparotomy
C
Diagnostic laparoscopy
D
Administration of intravenous metoclopramide
E
Initiation of intravenous broad-spectrum antibiotics

Answer

Placement of a nasogastric tube and intravenous fluids

The patient's presentation of colicky abdominal pain, vomiting, obstipation, and abdominal distension in the setting of prior abdominal surgery is highly suggestive of a small bowel obstruction (SBO) secondary to post-surgical adhesions. The CT scan confirms a mechanical SBO. Crucially, the patient exhibits no signs of complicated SBO (which would include fever, hemodynamic instability, significant leukocytosis, localized peritonitis, or CT evidence of bowel ischemia such as pneumatosis intestinalis or lack of wall enhancement). Because this is an uncomplicated SBO, the most appropriate next step in management is conservative. This consists of gastrointestinal decompression using a nasogastric tube, rigorous intravenous fluid resuscitation to correct volume depletion from vomiting and third-spacing, and bowel rest (nil per os). Observation with serial abdominal examinations is then required to monitor for resolution or signs of clinical deterioration.

Step-by-Step Solution

Evaluate the clinical presentation and physical exam.

The patient has crampy abdominal pain, nausea, vomiting, obstipation, abdominal distension, and high-pitched bowel sounds, which are classic signs of a mechanical small bowel obstruction.

Identifying the primary syndrome directs the subsequent diagnostic and management pathways.

Analyze the diagnostic studies to stratify disease severity.

Normal leukocyte count, normal vital signs, lack of peritonitis, and a CT scan showing bowel dilation without signs of ischemia or free air indicate an uncomplicated small bowel obstruction.

Differentiating between uncomplicated and complicated obstruction is critical because it dictates whether the initial management should be conservative or surgical.

Determine the appropriate management based on severity.

For an uncomplicated small bowel obstruction, the standard of care is conservative management with bowel rest, intravenous fluid resuscitation, and nasogastric tube decompression.

Conservative management successfully resolves the majority of adhesion-related small bowel obstructions, avoiding unnecessary surgical morbidity.

Key Concept

The initial management of a stable patient with an uncomplicated small bowel obstruction (no signs of ischemia, perforation, or peritonitis) is conservative, consisting of nasogastric tube decompression, intravenous fluids, and bowel rest.

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