Renal sarcoidosis in Christchurch, New Zealand 1970-1998

AIM: To identify patients presenting to a nephrologist in whom a diagnosis of sarcoidosis could be made, to assess the relevant causes of renal involvement and to review treatment and long-term follow-up of this group.

METHOD: A retrospective review of the computer database PROTON for patients given the diagnosis of sarcoidosis, followed by a case note review of identified patients with respect to the mode of presentation, clinical and laboratory features, treatment and subsequent follow-up.

RESULTS: Nineteen patients (15 males) were identified, mean age 45 years, all were Caucasian, and follow-up was four months to 26 years (mean 9.3 years). Most common mode of presentation was acute renal failure (11) during spring/summer (14). Evidence for systemic disease was present in all patients. Mean plasma creatinine on presentation was 0.52 mmol/L and calcium 3.01 mmol/L. Hypercalcaemia was present in 60%. Kidney biopsy was performed in seven patients with the predominant findings of tubular atrophy and interstitial fibrosis; significant granulomata were present in only two. Treatment in all patients was with corticosteroids with good result. Mean long term plasma creatinine was 0.17 mmol/L at 9.3 years. Steroid withdrawal was attempted in all patients, successful in five, with the mean time to relapse of five months in the remaining 14. Mean steroid dose in this group was 7.6 mg on long term follow-up.

CONCLUSIONS: Sarcoidosis causes renal dysfunction mainly through altered calcium metabolism. Treatment with corticosteroids is successful in improving renal function, but relapse is common on steroid withdrawal and prolonged treatment is necessary for disease control.