title: Metabolic investigation of patients with staghorn calculus: is it necessary?
abstract: OBJECTIVE
  To evaluate the prevalence of metabolic disorders in patients with staghorn calculi treated at the Regional Center of Lithiasis Metabolic Studies in central region of Såo Paulo State, Brazil.
  
  
  METHODS
  Between February 2000 and February 2008, 630 patients with urinary calculi were evaluated in the lithiasis outpatient clinic. Thirty-seven of them had staghorn calculi (35 women and 2 men). The inclusion criteria for the metabolic investigation included the absence of urological manipulation 30 days before the examination, negative urine culture and creatinine clearance > 60 mL/min. The protocol for metabolic investigation consisted of qualitative search for cystinuria. Two non-consecutive 24-hour urine samples collected to measure calcium, phosphorus, uric acid, sodium, potassium, magnesium, oxalate and citrate, and serum calcium levels, phosphorus, uric acid, sodium, potassium, magnesium, chloride, parathormone and urine pH.
  
  
  RESULTS
  Among patients with lithiasis, 5.9% (37/630) had staghorn calculus and in 48.6% (18/37) were diagnosed with urinary infection. The females were predominant for 94.5% of cases. The calculi were unilateral in 31 of cases and bilateral in six. Metabolic abnormalities were found in 68.2% of patients with hypercalciuria (64.2%) and hypocitraturia (53.3%) being the most common disorders.
  
  
  CONCLUSIONS
  The presence of metabolic disorders in nearly 70% of patients with staghorn calculus reinforces the necessity for evaluation of these patients. The diagnosis and treatment of identified metabolic abnormalities can contribute to the prevention of recurrent staghorn calculi.
authors.affiliation: Lithotripsy Service, School of Medicine, UNESP, Botucatu, Brazil.
authors.forename: Carmen R P
authors.initials: CR
authors.lastname: Amaro
authors.forename: Jose
authors.initials: J
authors.lastname: Goldberg
authors.forename: Aparecido D
authors.initials: AD
authors.lastname: Agostinho
authors.forename: Patricia
authors.initials: P
authors.lastname: Damasio
authors.forename: Paulo R
authors.initials: PR
authors.lastname: Kawano
authors.forename: Oscar E H
authors.initials: OE
authors.lastname: Fugita
authors.forename: Joao L
authors.initials: JL
authors.lastname: Amaro
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000150:complications* / Q000378:metabolism; D008297:Male; D008659:Metabolic Diseases / Q000150:complications*; D008875:Middle Aged; D011446:Prospective Studies; D014552:Urinary Tract Infections / Q000150:complications* / Q000382:microbiology; D014556:Urine / Q000737:chemistry*