A 65-year-old man is evaluated in the emergency department for severe, unremitting abdomin… — USMLE Step 2 CK

A $65$ -year-old man is evaluated in the emergency department for severe, unremitting abdominal pain that began abruptly $6$ hours ago. Earlier in the day, he experienced nausea, bilious vomiting, and abdominal bloating. He has not passed flatus or stool for the last $24$ hours. His medical history is significant for an open appendectomy $20$ years ago and essential hypertension. Vital signs are temperature $38.8^\circ\text{C}$ ( $101.8^\circ\text{F}$ ), blood pressure $90/60 \text{ mmHg}$ , heart rate $118/\text{min}$ , and respiratory rate $22/\text{min}$ . Physical examination reveals a distended abdomen with absent bowel sounds. There is significant tenderness to palpation in the right lower quadrant, accompanied by involuntary guarding and rebound tenderness. Laboratory studies show a leukocyte count of $18,500/\text{mm}^3$ and a serum bicarbonate of $14 \text{ mEq/L}$ . An arterial blood gas analysis on room air reveals a pH of $7.28$ and a $\text{PaCO}_2$ of $30 \text{ mmHg}$ . An upright abdominal radiograph demonstrates multiple dilated small bowel loops with air-fluid levels and a paucity of colonic gas. Which of the following is the most appropriate next step in the management of this patient?

A
Insert a nasogastric tube for decompression and perform serial abdominal examinations
B
Obtain a computed tomography scan of the abdomen and pelvis with intravenous contrast
C
Administer intravenous sodium bicarbonate to correct the metabolic acidosis
D
Initiate intravenous piperacillin-tazobactam and admit to the intensive care unit for observation
Proceed immediately to emergency exploratory laparotomyCevap

Cevap

Proceed immediately to emergency exploratory laparotomy

The correct answer is to proceed immediately to emergency exploratory laparotomy. This patient presents with classic clinical and radiographic evidence of a small bowel obstruction (SBO), most likely secondary to adhesions from his prior appendectomy. Crucially, his presentation is complicated by signs of bowel ischemia and strangulation. Key indicators of strangulation include systemic toxicity (fever, tachycardia, hypotension), significant leukocytosis, metabolic acidosis (evidenced by low bicarbonate and low pH due to lactic acidosis from ischemic tissue), and physical exam findings of peritonitis (involuntary guarding and rebound tenderness). When an SBO is complicated by signs of ischemia or peritonitis, the obstruction is considered a surgical emergency. The most appropriate next step is immediate exploratory laparotomy to resect any necrotic bowel and relieve the obstruction. Delaying surgery for further imaging or attempting conservative management in this setting significantly increases mortality.

Adım Adım Çözüm

Diagnose the primary condition based on history and imaging.

The patient has a small bowel obstruction (SBO), supported by the history of prior abdominal surgery (adhesions), bilious vomiting, obstipation, and radiographic evidence of dilated small bowel loops with air-fluid levels.

Identifying the mechanical obstruction is the first step in formulating a management plan.

Evaluate for complications such as bowel ischemia, strangulation, or perforation.

The patient exhibits fever (

38.8^\circ\text{C}

), hemodynamic instability (BP

90/60 \text{ mmHg}

, HR

118/\text{min}

), severe leukocytosis (

18,500/\text{mm}^3

), metabolic acidosis (pH

7.28

\text{HCO}_3^-

14 \text{ mEq/L}

), and peritonitis (rebound tenderness and guarding).

Differentiating between an uncomplicated SBO and a complicated SBO dictates whether medical or surgical management is indicated.

Determine the most appropriate next step in management.

Due to the clear evidence of complicated SBO with suspected bowel infarction and peritonitis, immediate surgical intervention is mandated.

Delaying surgery for further imaging or attempting conservative management in a patient with a strangulated SBO significantly increases mortality.

Anahtar Kavram

Patients presenting with a small bowel obstruction and signs of clinical deterioration (fever, hemodynamic instability, metabolic acidosis, leukocytosis) or peritonitis require emergent surgical exploration.

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