staghorn calculus

Introduction

A large urinary calculus within the renal pelvis (often shaped like a staghorn).

Pathology

• associated with struvite stones (magnesium ammonium phosphate)
• urinary tract infections including pyelonephritis are common
  • urea-splitting bacteria Proteus & Klebsiella are frequent pathogens
    • urea -> NH3 + CO2 thus they form in alkaline urine
  • less commonly Pseudomonas
• calcium phosphate stone most common; rarely form staghorn calculi

Complications

• struvite stones leading to staghorn calculus resulting from Pseudomonas infection can lead to sepsis & ESRD

Management

• stone removal
• antibiotic therapy

More general terms

• struvite (magnesium ammonium phosphate) stone
• nephrolithiasis; kidney stone