Types of Stones
stones, commonly called infectious stones, are composed of magnesium,
ammonium and phosphate. Struvite stones represent 7-31% of all renal
calculi. Struvite stones are produced from urease-containing bacteria
(i.e., Proteus, Klebsiella). Multimodal therapy includes percutaneous
nephrolithotomy possibly followed by extracorporeal lithotripsy
and chemolysis. For very large stones, anatrophic nephrolithotomy
is performed. Medical management with antimicrobial therapy, chemolysis
(hemiacidrin), urease inhibition (acetohydroxamic acid) and urinary
acidification helps to prevent stone recurrence.
or infection stones account for 15% - 20% of all renal calculi.
They occur more commonly in females with a female to male ratio
of 2:1. The stones are composed of magnesium ammonium phosphate
(struvite) and carbonate apatite (calcium carbonate and calcium
phosphate) and often obtain staghorn proportions. These stones are
always associated with urinary tract infections with urease splitting
bacteria (Proteus, Klebsiella, Pseudomonas
and less commonly, Staphylococcus aureus).
indications for stone removal include urinary tract infection, progressive
renal damage, urinary tract obstruction and persistent pain. Medical
therapy is only an adjunctive roll in the management of these patients
and is directed primarily at controlling the urinary tract infection
prior to, during, and subsequent to surgical removal. Administration
of Urease inhibitors (acetohydroxamic acid) may be useful in reducing
the incidence of stone recurrence in patients with intractable urinary
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