ANTIBIOTIC INDUCED ILLUSION – GALLBLADDER PSEUDOLITHIASIS

ANTIBIOTIC INDUCED ILLUSION – GALLBLADDER PSEUDOLITHIASIS
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INTRODUCTION:

Ceftriaxone is a widely used third-generation cephalosporin with broad–spectrum antimicrobial coverage and convenient once-daily dosing. Approximately 30-40% of ceftriaxone is excreted through the biliary system, where it reaches concentrations significantly higher than in serum. In the presence of calcium ions, ceftriaxone complexes, which precipitate in bile and accumulate within the gall bladder lumen. This phenomenon, termed as ceftriaxone- induced pseudolithiasis, represents a reversible drug related biliary precipitation that mimics true cholelithiasis.

First described in 1980s, it is more commonly reported in pediatric population, with an incidence ranging from 15-46% in some prospective ultrasound based studies. Most cases are asymptomatic and resolve spontaneously after discontinuation of the drug.

CLINICAL HISTORY:

A 42 year old female presented with chief complaints of loose stools and abdominal pain. Patient was started on IV ceftriaxone.

DISCUSSION:

Although widely described in literature, ceftriaxone-related biliary pseudolithiasis remains under-recognized in routine clinical practice. The pathogenesis is attributed to precipitation of calcium-ceftriaxone salts in bile.

Unlike true gallstones , these precipitates:

  • Develop rapidly (within 3-7 days of therapy)
  • Are reversible upon discontinuation
  • Do not represent cholesterol or pigment stone formation

Risk factors:

  1. High dose ceftriaxone therapy.
  2. Prolonged therapy
  3. Pediatric age group
  4. Fasting state
  5. Dehydration
  6. Renal impairment

Imaging characteristics:

Ultrasound:

  • Echogenic sludge or calculi-like material.
  • May or may not produce posterior acoustic shadowing.
  • Absence of inflammatory features unless complicated.
  • Normal biliary duct calibre.

CT may demonstrable hyperdense material within the gall bladder due to calcium content.

Unlike true gallstones, these deposits resolve completely after discontinuation of the drug, which serves as the most important diagnostic clue.

Clinical significance:

Awareness of reversible entity prevents unnecessary surgical referral, misdiagnosis of acute cholecystitis and avoidable cholecystectomy, particularly in pediatric patients.

CONCLUSION:

Ceftriaxone-induced gall bladder pseudolithiasis is a reversible, drug-related biliary precipitation that mimics true gallstones on imaging. Recognition of the temporal association with ceftriaxone therapy and confirmation with follow up ultrasound are essential to prevent unnecessary surgical intervention.

Dr Akila

Dr. Akila
Radiology Resident
Kauvery Hospital, Chennai.

Dr. Vijay Thiraviyam
Senior Resident – Radiology
Kauvery Hospital, Chennai.