🦠 Severe Diverticulitis Requiring Admission

Scenario:

A 55‑year‑old woman presents with 48 hours of severe left lower‑quadrant pain, fever (38.5 °C), and inability to tolerate oral intake. She reports nausea and has been unable to pass flatus. On examination she is tender in the left lower quadrant with guarding but no peritonism. Her white cell count is 16 × 10^9/L, and CRP is elevated. A CT scan confirms uncomplicated diverticulitis (no abscess or perforation) with marked pericolic fat stranding. Given her pain, systemic features and inability to eat, you admit her for IV antibiotic therapy.

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Question:
Which empiric IV regimen is most appropriate on admission?

A) Piperacillin–tazobactam
B) Ceftriaxone + metronidazole
C) Ertapenem
D) Meropenem
E) Ampicillin–sulbactam

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✅ Preferred Answer: A) Piperacillin–tazobactam

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📘 Mini‑Lesson & Discussion

• Spectrum Required:

  • Gram‑negative rods (e.g. E. coli)

  • Anaerobic bacteria

• Why Piperacillin–Tazobactam?

  • Single‑agent coverage of both Gram‑negatives and anaerobes

  • Proven efficacy in moderate–severe diverticulitis

• Alternative IV Option:

  • C) Ertapenem: excellent single‑agent cover, especially if ESBL risk is high; however, reserving carbapenems helps curb resistance.

• Why Not the Others?

  • B) Ceftriaxone + metronidazole: two‑drug approach workable, but dual infusions are less convenient than piperacillin–tazobactam.

  • D) Meropenem: broadest spectrum but overkill in uncomplicated disease; reserve for documented resistant organisms.

  • E) Ampicillin–sulbactam: rising resistance among E. coli limits reliability.

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🏠 Discharge Strategy

Once clinically improved, afebrile, and tolerating diet, switch to oral therapy for a total 7–10 days:

• Single‑agent option:

  • Moxifloxacin (covers both Gram‑negatives and anaerobes).

• Two‑drug option:

  • Ciprofloxacin plus metronidazole.

⚠️ Note: Amoxicillin–clavulanate (Augmentin) is no longer recommended for diverticulitis in many regions due to high resistance rates among E. coli and anaerobes.

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💡 Teaching Pearls

• Admission Criteria: Severe pain, systemic signs, or inability to tolerate oral intake necessitate IV admission even in uncomplicated CT findings.

• Single‑Agent vs. Combination: Favour single agents that cover the required spectrum to simplify care and reduce line‑related complications.

• Antibiotic Stewardship: Reserve carbapenems for documented resistant infections; avoid agents with known high local resistance (e.g. Augmentin in diverticulitis).

• Oral Step‑Down: Choose oral agents with reliable bioavailability and spectrum; moxifloxacin or ciprofloxacin + metronidazole are preferred.

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