Emergency medical services bring a 58-year-old male to the acute care bay complaining of r… — USMLE Step 2 CK

Emergency medical services bring a 58-year-old male to the acute care bay complaining of relentless, diffuse abdominal pain that started two days ago. The patient reports having vomited bilious material several times and notes a complete inability to pass stool or flatus since the pain began. His surgical history is significant for an open appendectomy a decade ago. Vital signs show a temperature of $39.2^\circ\text{C}$ ( $102.6^\circ\text{F}$ ), a heart rate of $122/\text{min}$ , and a blood pressure of $86/54\text{ mmHg}$ . Abdominal examination demonstrates marked distension, tympany to percussion, and exquisite diffuse tenderness accompanied by board-like rigidity and rebound tenderness. Laboratory evaluation is notable for a leukocyte count of $19,500/\text{mm}^3$ and a serum lactate level of $4.8\text{ mmol/L}$ . Venous blood gas reveals a pH of $7.28$ and a bicarbonate concentration of $14\text{ mEq/L}$ . Which of the following is the most appropriate next step in management?

A
Nasogastric tube decompression and intravenous fluid resuscitation
B
Computed tomography scan of the abdomen with intravenous contrast
Emergent exploratory laparotomyAnswer
D
Intravenous piperacillin-tazobactam and clinical observation
E
Intravenous sodium bicarbonate infusion

Answer

The most appropriate next step in management is emergent exploratory laparotomy.

The correct answer is emergent exploratory laparotomy. This patient presents with classic signs of a small bowel obstruction (SBO) caused by postoperative adhesions, complicated by bowel strangulation. Uncomplicated SBO typically presents with colicky abdominal pain, vomiting, and distension, and is managed initially with bowel rest, nasogastric tube decompression, and intravenous fluids. However, this patient exhibits classic 'red flag' signs of strangulation and ischemia: fever, hemodynamic instability (hypotension, tachycardia), peritonitis (rigidity, rebound tenderness), pronounced leukocytosis, and lactic acidosis. Once signs of ischemia or peritonitis develop, the standard of care immediately shifts from conservative management to emergent surgical exploration. Delaying source control in a patient with a necrotic bowel segment results in rapidly progressive sepsis and a high mortality rate.

Step-by-Step Solution

Identify the underlying primary pathology based on the clinical presentation.

The combination of colicky abdominal pain, bilious vomiting, obstipation, marked abdominal distension, and a history of prior abdominal surgery strongly indicates a small bowel obstruction (SBO).

Prior abdominal surgeries frequently cause adhesions, which are the most common cause of mechanical SBO in adults.

Evaluate the patient's clinical stability and look for signs of complications.

The patient exhibits hemodynamic instability (hypotension, tachycardia), signs of systemic inflammatory response (high fever, pronounced leukocytosis), peritonitis (rigidity, rebound tenderness), and metabolic acidosis with elevated lactate.

These findings indicate that the SBO has progressed to bowel ischemia and strangulation, meaning a segment of the intestine has lost its blood supply and is becoming necrotic.

Determine the definitive management strategy based on the presence of complications.

Because there are overt signs of bowel strangulation and peritonitis, conservative medical management and delayed imaging are contraindicated; immediate surgical intervention is required.

Emergent exploratory laparotomy is necessary to resect the necrotic bowel, restore continuity or create an ostomy, and resolve the underlying mechanical obstruction.

Key Concept

Patients with a small bowel obstruction who develop signs of bowel strangulation or peritonitis (e.g., fever, hemodynamic instability, guarding, rebound tenderness, metabolic acidosis) require emergent exploratory laparotomy.

Question

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Topics

More questions from this topic