Clinical Features of Stones Associated with a Urinary Tract Infection (Infection Stones)

 

Urinary tract infection (UTI):

(1) chronic UTI with urea splitting (urease positive) bacteria (Proteus, other)

(2) anatomic or structural disorder predisposing to infection

 

Urea is split into:

(1) ammonium

(2) bicarbonate

 

Stones that develop:

(1) magnesium ammonium phosphate (struvite)

(2) carbonate apatite (Dahllite, form of calcium phosphate)

(3) ammonium urate

 

Features:

(1) stones form as a cast of the urinary system (staghorn, other)

(2) alkaline urine (pH above 6.8)

(3) pyruria

(4) positive urine culture for urea-splitting bacteria