Q: My son is 28 years old. From the past one year he is suffering from low grade fever (99-100F), occasional cough, insufficiency of breath and chronic fatigue. His chest x-ray and CT scan of lungs are normal. Blood Tests of Hb, TLC, DLC, ESR, anti-nuclear antibody, ds-DNA, C-reactive protein, rheumatoid factor, serum angiotensin converting (ACE) were normal. His ECG and echocardiogram were normal. Lung Function is also normal. Only his 1,25 dihydroxyvitamin D (vit D3) levels are 52.60 pg/ml for which the reference range is 15 - 55pg/ml. He has developed a chronic phosphate loss through urine (phosphaturia). The doctors who treated him are unsure of his condition. I mailed his medical information to medical websites, some of them replied that this may be an early case of sarcoidosis. For them the maximum serum VitD3 is 45pg/ml. They also mentioned sarcoid granulomas generate excess Vit D3 apart from kidneys. My son avoided direct sunlight according to doctor's advice and has not taken any Vit D supplements. Yet he has high VitD3 serum levels. Does he have sarcoidosis or any other autoimmune disease? Please prescribe the test to confirm the diagnosis? Are high VitD3 levels due to hidden sarcoidosis or phosphaturia?

A:I agree your son's condition appears puzzling and I agree with the others that a diagnosis of sarcoidosis can be logically considered in the presence of hyperphosphaturia and the serum D3 level. Sarcoidosis can be very difficult to diagnose when the chest x-ray is normal. But the condition can cause granulomas- sometimes very tiny and difficult to pick up. My suggestion is that he should have investigations concentrated on the liver functions as well as the relevant scans for a possible clue to the diagnosis. However, speaking as a clinician I would get his urine repeatedly checked for infection, which in subclinical form may account for his raised temperature and if so an appropriate antibiotic should help. If your son feels really ill generally, a short course of steroids can be effective but it is important to exclude tuberculosis before using steroid treatment.