A 70-year-old Caucasian male presented with history of systemic symptoms lasting since several weeks including malaise, anorexia, weight loss, and low-grade fever. He had no other significant symptoms or clinical findings, physical examination was unrevealing, and vital parameters were normal. When the patient was 45 yeas old, a diagnosis of pulmonary sarcoid was made upon results of radiologic imaging tests, gallium-67 scanning, and the histological demonstration of non-caseating granulomas at a transbronchial lung biopsy. At that time, all other known causes of granulomatous lung inflammation were ruled out and complete recovery was achieved after 6 months of steroid treatment at tapering doses. Afterwards, he had several episodes of recurrent right flank pain, which were managed conservatively; 10 months before admission lithotripsy was performed and calcium oxalate urinary stones recovered. At that time, serum creatinine was 2.1 mg/dl (normal range 0.5-1.2 mg/dl), urea was 72 mg/dl (normal range 10-50 mg/dl), and calcium was 12.4 mg/dl (normal range 8.1-10.4 mg/dl). Follow-up laboratory results until 1 month before presentation revealed persistent mild hypercalcaemia, with calcium blood levels ranging from 10.6 to 11.2 mg/dl, and stable serum creatinine and urea levels; the other variables remained within normal ranges on each occasion. There was no personal and family history of hypertension or any other cardiovascular, metabolic or systemic disorders, and the patient denied alcohol use, toxic habits, or taking any other medications, including over-the-counter medications, or herbal remedies. On admission, laboratory analyses showed renal impairment with a glomerular filtration rate of 14 ml/min; serum creatinine was 4.1 mg/dl, urea was 106 mg/dl, and calcium was 14.4 mg/dl. Electrolytes, a complete blood count, uric acid, cholesterol, triglycerides, protein, amylase and lipase, liver function tests, intact parathyroid hormone, and the coagulation profile were all normal; the erythrocyte sedimentation rate was 50 mm/h. Urinalysis showed a pH of 6.5, a specific gravity of 1012, and the urine tested positive for occult blood; there were between 5 and 10 red cells and calcium oxalate crystals per high-power field with no white cells, casts, or bacteria. Cultures grew no pathogens and the 24h urinary protein excretion was < 500 mg. Complement was normal and search for autoantibodies, including antinuclear, antiphospholipid, and antineutrophil cytoplasmic antibodies, rheumatoid factor, cryoglobulins, and lupus anticoagulant was also negative; blood levels of angiotensin-converting enzyme (ACE) were not measured at this time. An electrocardiogram did not show any abnormalities and a chest
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