title: Characteristics of patients with staghorn calculi in our experience.
abstract: OBJECTIVE
  To elucidate the factors contributing to staghorn stone formation in patients.
  
  
  METHODS
  The records of 82 patients (44 men and 38 women) with complete staghorn calculi were reviewed retrospectively for clinical presentation, metabolic disturbances and anatomical abnormalities.
  
  
  RESULTS
  There were 79 unilateral and three bilateral cases. The patient performance of the activities of daily life was assessed with the modified Rankin scale (MRS) and it was found that 69 patients were functionally independent (84.1%, MRS 0-1) and 10 patients had a severe disability (12.2%, MRS 4-5). Seven patients had chronic indwelling catheters (8.5%). A positive urine culture was found in 24.4% of patients. Analysis of stone composition revealed magnesium ammonium phosphate and mixed calcium oxalate-phosphate were the most frequently identified types of stone (32.1% and 22.2%, respectively). Urinary pH was low in patients with uric acid stones (mean 5.4). Hyperuricemia, cystinuria and hypercalciuria were found in 14.6%, 2.4% and 37.8%, respectively. Hypercalciuria was found more frequently in calcium-stone cases. Eleven patients (13.4%) showed structural abnormalities of the kidney.
  
  
  CONCLUSIONS
  Our data show that the patients with severe disability, urinary tract infection and hypercalciuria could be recognized more frequently in staghorn calculi compared with common urolithiasis. However, in Western countries, the frequency of both urinary tract infection and struvite stones is much higher than in our data. Other Japanese authors have also reported the low frequency of struvite stones in staghorn calculi, suggesting that various factors other than urinary tract infection possibly contribute to the formation of staghorn calculi in Japan.
authors.affiliation: Department of Urology, Sanjukai Hospital, Sapporo, Hokkaido, Japan. akagashi@sanjukai.or.jp
authors.forename: Keigo
authors.initials: K
authors.lastname: Akagashi
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Tanda
authors.forename: Shuji
authors.initials: S
authors.lastname: Kato
authors.forename: Shigeki
authors.initials: S
authors.lastname: Ohnishi
authors.forename: Hisao
authors.initials: H
authors.lastname: Nakajima
authors.forename: Akihito
authors.initials: A
authors.lastname: Nanbu
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Nitta
authors.forename: Mikio
authors.initials: M
authors.lastname: Koroku
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Sato
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Hanzawa
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D002118:Calcium / Q000652:urine; D002129:Calcium Oxalate / Q000032:analysis; D002130:Calcium Phosphates / Q000032:analysis; D002408:Catheters, Indwelling; D003555:Cystinuria / Q000150:complications; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D033461:Hyperuricemia / Q000150:complications; D007668:Kidney / Q000002:abnormalities; D007669:Kidney Calculi / Q000737:chemistry* / Q000150:complications* / Q000175:diagnosis / Q000628:therapy; D017616:Magnesium Compounds / Q000032:analysis; D008297:Male; D008875:Middle Aged; D010710:Phosphates / Q000032:analysis; D012189:Retrospective Studies; D000069877:Struvite; D014527:Uric Acid / Q000032:analysis; D014552:Urinary Tract Infections / Q000209:etiology; D014556:Urine / Q000382:microbiology / Q000502:physiology
chemical_list: D002130:Calcium Phosphates; D017616:Magnesium Compounds; D010710:Phosphates; D002129:Calcium Oxalate; D014527:Uric Acid; D000069877:Struvite; D002118:Calcium