“Isolated” granulomatous interstitial nephritis and renal failure: an unusual presentation of sarcoidosis

• Main Author: Farinha,Ana
• Publication Date: 2012
• Other Authors: Assunção,José, Felgueiras,Joana, Vinhas,José
• Format: Article
• Language: eng
• Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Download full: http://scielo.pt/scielo.php?script=sci_arttext&pid=S0872-01692012000400011
• topic: Chronic kidney disease; granulomatous interstitial nephritis; hypercalcaemia; sarcoidosis

Sarcoidosis is a multisystemic granulomatous disorder of unknown aetiology typically affecting the lungs and lymph nodes. Less frequently, the kidneys may also be affected. Postmortem analysis suggests that 20 percent of patients have histologic changes in the kidney. However, clinical involvement of the kidney is a relatively uncommon condition. Renal failure may occur associated with hypercalcaemia, glomerular disease, or granulomatous interstitial nephritis. Renal failure associated with isolated granulomatous interstitial nephritis is an extremely rare entity, with only 57 cases reported until 1990, and the clinical presentation may be misleading. We report a case of a 52-year-old man complaining of persistence of symptoms of lethargy and anorexia, admitted for hypercalcaemia and progressive renal failure. One year earlier, he presented to his primary care physician with a 3-month history of fatigue, anorexia and weight loss. At that time, laboratory findings showed renal failure with a raised serum creatinine of 2.8 mg/dL, and evidence of mesenteric lymphadenopathy on abdominal CT scan. However, as spontaneous regression of lymphadenopathy occurred, the clinical picture was attributed to a depression syndrome. During hospital stay, patient underwent a renal biopsy which showed a granulomatous interstitial nephritis with Schaumann bodies and led to a diagnosis of sarcoidosis. He was treated with steroids with disappearance of constitutional symptoms and partial recovery of renal function. Renal sarcoidosis should be considered in the differential diagnosis of hypercalcaemia and renal failure. A raised serum angiotensin-converting enzyme may aid in making the diagnosis, but a renal biopsy is essential to confirm the diagnosis. Timely diagnosis is critical to successful therapy, as the condition usually responds to early treatment with corticosteroids