What is staghorn kidney stone?Staghorn kidney stones are "staghorn-like" (branched antlers of deer) renal calculi. Staghorn stones are branched and occupy a large portion of the renal pelvis and one or more of calices.
AdvertisementsThe staghorn calculus is termed "partial staghorn calculus" when it occupies part of the renal collecting system. If the calculus occupies the entire collecting system, it is termed as a "complete staghorn calculus".
Formation of staghorn kidney stonesSome of the main types of renal calculi are oxalate, phosphate, struvite, calcium carbonate apatite and cystine stones. The calcium oxalate stones are formed due to excessive oxalate and calcium, in acidic urine. The growth of oxalate calculi is slow and very rarely they grow into staghorn calculi. The phosphate calculi are formed due to certain medical conditions and disorders. The phosphate calculi also normally do not grow into staghorn stones.
The struvite calculi, which are composed of magnesium ammonium phosphate and/or in combination with calcium carbonate apatite, are formed due to infection in the upper urinary tract by urease forming organisms.
Renal calculi composed of cystine or uric acid, either in pure form or mixed with other components may also grow into staghorn filling the renal pelvis as well as the calices. Mucoproteins and biofilm exopolysaccharides produced by microbes may provide matrix for the formation of these renal calculi. Even after active treatment, there is always the possibility of recurrence due to persisting infection or staghorn calculi debris.
Renal failureActive treatment is advised for the newly diagnosed patient. As the staghorn kidney stones may not cause renal colic, often show symptoms of dull pain only, the patient tend to neglect treatment. The staghorn kidney stones, if not treated early and properly, have the great risk of causing renal failure and/or life threatening sepsis.
Complete removal of the staghorn calculus along with its fragments and debris, eradication of the causative organisms and removal of obstructions, can only protect from the progressive renal damage. Nonsurgical conservative treatment and supportive measures such as use of antibiotics and urease inhibitors may give temporary relief, but active treatment is necessary for protection from permanent renal damage.
Treatment modalitiesThe American Urological Association (AUA) had in their guidelines report on the management of staghorn kidney stones recommended certain treatment modalities. Recommended treatment modalities are, percutaneous nephrolithotomy (PNL) monotherapy, shock-wave lithotripsy (SWL) monotherapy, combination therapy, open surgery or nephrectomy.
Percutaneous nephrolithotomy is the most prefered treatment option. Open surgery is considered in patients with extremely large staghorn calculi. Patients with extreme morbid obesity, skeletal abnormalities or unfavorable collecting-system are candidates for open surgery. In patients with chronic infection and severe renal damage, nephrectomy is the best option to prevent further patient morbidity and loss of life. Focus must be on complete removal of the staghorn calculus and treatment of infection.
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