[Acute kidney failure in a recurrence of sarcoidosis at the height of summer].

History And Findings: A 35-year-old woman with sarcoidosis, successfully treated 3 years previously, developed fatigue, nausea and loss of weight during a summer holiday in Italy where she was exposed to much bright sun. There had been no previous recurrence of the sarcoidosis. On return she was found to be in renal failure with marked hypercalcaemia. Physical examination merely revealed peasized non-tender submandibular and cervical lymph nodes, but was otherwise unremarkable.

Investigations: Serum creatinine and calcium concentrations (3.8 mg/dl and 3.6 mmol/l) were markedly elevated. Computed tomography showed an enlarged submandibular lymph node, but no other organ abnormality. Biopsy of the salivary gland demonstrated recurrent sarcoidosis.

Treatment And Course: Calcium concentration became normal (2.4 mmol/l) within two weeks of treatment with methylprednisolone (100 mg daily for 3 days, followed by gradual reduction to 30 mg daily for 3 months, until discontinued slowly). Creatinine concentration, which had fallen to 1.5 mg/dl, was at the upper limit of normal (1.1 mg/dl) after 4 months and 0.8 mg/dl after 8 months.

Conclusion: Marked exposure to UV light should be avoided in patients with a history of recent sarcoidosis, because it increases the formation of vitamin D3 precursors: In the case of recurrent sarcoidosis, these precursors are converted to 1,25 dihydroxyvitamin D3 in the sarcoidosis granulomas. This can lead to severe complications, such as hypercalcaemia and renal failure.