A 62-year-old man presents to the emergency department with a 3-day history of worsening l… — USMLE Step 2 CK

A $62$ -year-old man presents to the emergency department with a $3$ -day history of worsening left lower quadrant abdominal pain, fever, and anorexia. His temperature is $38.8^\circ\text{C}$ ( $101.8^\circ\text{F}$ ), blood pressure is $122/78\text{ mm Hg}$ , and pulse is $102/\text{min}$ . Physical examination demonstrates significant focal tenderness and guarding in the left lower quadrant without diffuse peritonitis. Laboratory testing shows a leukocyte count of $17,200/\text{mm}^3$ with a left shift. Empiric broad-spectrum intravenous antibiotics are initiated immediately. Assuming the initial diagnostic imaging confirms acute complicated diverticulitis with a $5\text{ cm}$ pericolic abscess, arrange the following management steps in the most appropriate chronological sequence.

1Obtain computed tomography (CT) of the abdomen and pelvis with intravenous contrast
2Perform percutaneous image-guided catheter drainage of the pericolic abscess
3De-escalate empiric broad-spectrum antibiotics to targeted therapy based on fluid culture results
4Perform diagnostic colonoscopy $6$ to $8$ weeks after resolution of the acute episode
5Consult general surgery for elective segmental sigmoid resection

Answer

The correct chronological sequence for managing this patient is: 1) CT of the abdomen and pelvis with contrast, 2) Percutaneous image-guided catheter drainage, 3) De-escalation to targeted antibiotics, 4) Delayed diagnostic colonoscopy, and 5) Elective segmental sigmoid resection.

The standard of care for suspected acute diverticulitis begins with diagnostic CT imaging. Upon identification of a macro-abscess (generally

>3\text{ cm}

), the immediate next step is percutaneous drainage to achieve source control. Once cultures are obtained from the drain, broad-spectrum antibiotics should be de-escalated to targeted therapy to adhere to antibiotic stewardship guidelines. After the acute episode fully resolves (typically

6

8

weeks later), a delayed colonoscopy is mandatory to rule out an underlying malignancy that may have precipitated the perforation. Finally, because the patient experienced a complicated episode (abscess), they should be evaluated for a definitive elective sigmoid resection to prevent future life-threatening recurrences.

Step-by-Step Solution

Obtain CT of the abdomen and pelvis with contrast

Confirms the diagnosis of acute complicated diverticulitis and localizes the

5\text{ cm}

pericolic abscess.

This is the safest and most accurate initial diagnostic test. Acute colonoscopy is strictly contraindicated due to perforation risk.

Perform percutaneous image-guided catheter drainage

Achieves prompt source control of the infection and provides fluid for microbiological culture.

Abscesses larger than

3

4\text{ cm}

typically do not resolve with antibiotics alone and require drainage. This avoids emergency multi-stage surgery (Hartmann procedure).

De-escalate empiric antibiotics to targeted therapy

Narrows the antimicrobial spectrum based on specific culture sensitivities from the drained fluid.

Aligns with antibiotic stewardship to prevent resistance and secondary infections (e.g., C. difficile) once the pathogen is identified.

Perform delayed diagnostic colonoscopy

Evaluates the colonic mucosa to rule out underlying malignancy.

Diverticulitis can radiographically mimic colon cancer. Delaying the procedure

6

8

weeks allows inflammation to subside, minimizing perforation risk.

Consult surgery for elective resection

Removes the diseased segment of the sigmoid colon in a controlled, single-stage operation.

Patients who survive an episode of complicated diverticulitis are at high risk for recurrence, making elective resection the definitive long-term treatment.

Key Concept

Management algorithm for acute complicated diverticulitis with abscess formation

Estimated Time:2m 30s

Question

Answer

Step-by-Step Solution

Key Concept

Common Mistakes

Topics

More questions from this topic