During morning rounds on the surgical ward, the care team evaluates a patient recovering f… — USMLE Step 2 CK

During morning rounds on the surgical ward, the care team evaluates a patient recovering from a radical cystoprostatectomy and ileal conduit formation performed $48$ hours ago for high-grade urothelial carcinoma. The patient reports generalized fatigue and mild nausea but no acute distress. Vital signs include a temperature of $38.7^\circ\text{C}$ ( $101.7^\circ\text{F}$ ), heart rate of $95/\text{min}$ , blood pressure of $128/78\text{ mmHg}$ , and respiratory rate of $18/\text{min}$ . Auscultation of the chest reveals faint crackles at both lung bases. Abdominal examination demonstrates mild distension without rigidity or guarding; bowel sounds are absent. The stoma appears pink and healthy. The ostomy appliance contains $180\text{ mL}$ of cloudy, mucus-laden urine collected over the past four hours.

Laboratory studies obtained this morning reveal the following:
Leukocyte count: $11,500/\text{mm}^3$
Sodium: $139\text{ mEq/L}$
Potassium: $4.6\text{ mEq/L}$
Chloride: $110\text{ mEq/L}$
Bicarbonate: $18\text{ mEq/L}$
Blood urea nitrogen: $22\text{ mg/dL}$
Creatinine: $1.1\text{ mg/dL}$

Based on these clinical findings, which of the following is the most appropriate next step in management?

Initiate targeted incentive spirometry and encourage early ambulationAnswer
B
Administer broad-spectrum intravenous antibiotics after obtaining blood and urine cultures
C
Obtain a computed tomography scan of the abdomen and pelvis with intravenous contrast
D
Administer an intravenous bolus of sodium bicarbonate
E
Place a nasogastric tube for decompression and prepare for possible surgical exploration

Answer

Initiate targeted incentive spirometry and encourage early ambulation

The most appropriate next step is initiating incentive spirometry and early ambulation. This patient's clinical presentation represents a combination of normal physiological responses and benign, anticipated postoperative changes following an ileal conduit urinary diversion. Fever on postoperative day 2 accompanied by basilar crackles is highly characteristic of atelectasis. The cloudy, mucus-laden urine is an expected finding because the intestinal mucosa of the conduit continues to actively secrete mucus. Furthermore, the laboratory results show a mild hyperchloremic (normal anion gap) metabolic acidosis. This occurs because the ileal segment reabsorbs chloride and ammonium from the urine while secreting bicarbonate. Finally, absent bowel sounds and mild distension at 48 hours reflect a standard postoperative ileus following laparotomy. Because there are no indications of a true pathological emergency, standard pulmonary toilet is the correct management strategy.

Step-by-Step Solution

Analyze the timing and nature of the postoperative fever.

A temperature of

38.7^\circ\text{C}

on postoperative day 2 accompanied by basilar crackles is identified.

Atelectasis ('wind') is the most common cause of early postoperative fever, typically peaking at 48 hours, and requires pulmonary toilet.

Evaluate the significance of the urinary findings.

The urine is cloudy and heavily laden with mucus.

The intestinal mucosa utilized for the ileal conduit naturally secretes copious amounts of mucus. This is a physiological feature of the diversion, not a sign of pyuria or infection.

Interpret the basic metabolic panel.

The patient has a normal anion gap metabolic acidosis (

Na^+ - (Cl^- + HCO_3^-) = 139 - (110 + 18) = 11

Ileal mucosa functionally reabsorbs ammonium chloride and secretes bicarbonate from the urine into the bloodstream, creating a classic, expected hyperchloremic metabolic acidosis.

Assess the abdominal examination findings.

Mild distension and absent bowel sounds are noted 48 hours post-laparotomy.

This presentation is entirely consistent with an expected postoperative ileus following major abdominal surgery and bowel anastomosis.

Determine the appropriate intervention.

The correct action is to provide supportive pulmonary care.

Because all clinical and laboratory abnormalities represent expected physiological consequences of the surgical procedure, invasive diagnostics or aggressive pharmacologic treatments are contraindicated.

Key Concept

Normal physiological changes following ileal conduit urinary diversion include mucus-laden urine and hyperchloremic metabolic acidosis, which must be distinguished from postoperative complications.

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