Is this patient with recent broad‑spectrum antibiotic exposure, fever, leukocytosis, abdominal pain, ileus and colonic wall thickening on imaging (no diarrhea) having an active severe Clostridioides difficile infection?

Is This Active Severe C. difficile Infection?

Yes, this patient almost certainly has active severe Clostridioides difficile infection (CDI) presenting as ileus without diarrhea, and requires immediate aggressive treatment plus urgent surgical consultation.

Why Diarrhea Is Not Required for CDI Diagnosis

The absence of diarrhea does not exclude CDI. Multiple guidelines explicitly recognize ileus as a compatible clinical presentation of CDI 1. The ESCMID guideline defines ileus in CDI as "signs of severely disturbed bowel passage such as vomiting and absence of stool, combined with radiological signs of bowel distension" 1. This patient meets these criteria precisely.

A critical pitfall: Up to 30% of surgical patients with CDI may lack diarrhea initially due to colonic dysmotility 1. In fact, absence of diarrhea may signal progression to fulminant infection 1. Recent case series demonstrate that CDI without diarrhea can rapidly progress to toxic megacolon, with mortality rates approaching 40% in patients requiring colectomy 2.

This Patient Meets Multiple Criteria for Severe CDI

Clinical and Laboratory Markers of Severity

Your patient demonstrates virtually all the markers that guidelines associate with severe disease 1:

• Marked leukocytosis (>15 × 10⁹/L is a severity marker) 1
• Fever (core temperature >38.5°C indicates severe disease) 1
• Abdominal pain with signs of ileus 1
• Recent broad-spectrum antibiotic exposure (the primary risk factor) 1
• Radiologic findings: colonic wall thickening is specifically listed as an imaging marker of severe CDI 1

The 2019 WSES guidelines emphasize that leukocytosis >15 × 10⁹/L is a validated predictor of severe CDI and poor outcomes 1. The combination of fever, leukocytosis, and imaging findings has been shown to accurately stratify patients into severe disease categories 1.

Diagnostic Approach in This Clinical Context

When to Test and How

Test this patient immediately for C. difficile toxins, even without diarrhea 1. The IDSA guideline specifically states: "The diagnosis of C. difficile should be strongly considered if the patient has received antibiotics...and for any older patient with severe leukocytosis (≥30,000 cells/mm³), even in the absence of abdominal pain, diarrhea, or recent antibiotic use" 1.

• Send stool for C. difficile toxin testing (enzyme immunoassay for toxins A and B has 60-90% sensitivity) 1
• If available, nucleic acid amplification testing (NAAT) has higher sensitivity (80-100%) 1
• Do not wait for test results to start treatment in this high-risk presentation 1

Role of Imaging

CT imaging is already obtained and shows colonic wall thickening—this supports the diagnosis 1. The WSES guidelines note that CT findings including colonic wall thickening >4mm, pericolonic stranding, and unexplained ascites have 93% specificity for CDI 1. While CT sensitivity is only 52-70%, it is valuable for assessing severity and complications 1.

When Endoscopy Is Indicated

Avoid colonoscopy in this patient given the high clinical suspicion and severe presentation 1, 3. Full colonoscopy is contraindicated in severe or fulminant colitis due to perforation risk 1, 3. Flexible sigmoidoscopy may be considered only if stool tests are negative despite high clinical suspicion 1, 3, but this patient's presentation is so classic that empiric treatment is warranted immediately.

Immediate Management Algorithm

Step 1: Start Treatment Without Delay

This patient requires multi-route therapy because ileus prevents adequate oral drug delivery to the colon 1, 4:

• Vancomycin 125mg orally or via nasogastric tube four times daily 1, 4
• PLUS metronidazole 500mg intravenously every 8 hours 1, 4
• PLUS vancomycin 500mg in 100-500mL normal saline per rectum as a retention enema every 6 hours 1, 4

The rationale: intravenous metronidazole alone achieves poor colonic concentrations when ileus is present, necessitating direct colonic delivery of vancomycin 1, 4.

Step 2: Discontinue Inciting Antibiotics

Stop all non-essential antibiotics immediately 1. If antibiotics are absolutely required for another infection, narrow the spectrum as much as possible 1.

Step 3: Avoid Medications That Worsen Outcomes

• Do not use antiperistaltic agents (loperamide, diphenoxylate) 1
• Minimize or avoid opioid analgesics as they can precipitate toxic megacolon 1
• Do not give stool softeners, suppositories, or enemas for presumed constipation 2—this delays diagnosis and can worsen outcomes

Step 4: Obtain Urgent Surgical Consultation

Call surgery now 1, 4. Indications for immediate surgical consultation include 1, 4:

• Ileus (this patient has it)
• Severe systemic inflammation with leukocytosis (present)
• Colonic distension on imaging (present)
• Elevated serum lactate (check this urgently—it predicts need for surgery) 1

Early subtotal colectomy with end ileostomy is the procedure of choice if medical therapy fails 1, 4. Delayed surgery dramatically increases mortality—one series showed 40% mortality in patients requiring colectomy for CDI without diarrhea 2.

Step 5: Supportive Care

• Correct electrolyte abnormalities, especially potassium and magnesium 1
• Maintain hemodynamic stability with intravenous fluids
• Monitor for signs of toxic megacolon (worsening distension, peritonitis, shock)

Monitoring Treatment Response

Reassess after 3 days of therapy 1:

• Look for decreased fever, reduced abdominal pain and distention 1
• Check for declining white blood cell count 1
• Repeat imaging if clinical status is unclear 1
• If no improvement or worsening occurs within 3-5 days, proceed urgently to colectomy 1, 4

Metronidazole may take 3-5 days to show clinical response, but do not delay surgery if the patient deteriorates 1.

Key Clinical Pitfalls to Avoid

1. Assuming CDI requires diarrhea—ileus is a recognized presentation, especially in surgical patients 1, 2

2. Treating presumed constipation with laxatives or enemas—this delays diagnosis and can precipitate toxic megacolon 2

3. Relying solely on oral vancomycin when ileus is present—drug delivery to the colon is severely compromised 1, 4

4. Delaying surgical consultation—early involvement saves lives; waiting until the patient is moribund increases mortality dramatically 1, 4, 2

5. Continuing broad-spectrum antibiotics—these perpetuate CDI and worsen outcomes 1

6. Using antiperistaltic agents or opioids liberally—these can mask deterioration and precipitate toxic megacolon 1