Dihydroxyadenine crystalline nephropathy: an under-recognized cause of rapidly progressive renal failure. A Nephrology picture

Impaired kidney function was discovered in a 57-year-old man seeking medical advice for elevated blood pressure.Urine output had decreased in the 3 days before referral.There was no past history of renal disease or nephrotoxic drug intake.The patient denied a family history of kidney diseases.At presentation, examination revealed anasarca and elevated blood pressure (150/100 mmHg), but no hepatomegaly or splenomegaly.Heart bruits were normal, and chest ascultation was clear.Laboratory investigations revealed serum creatinine of 2.3 mg/dl and urea of 98 mg/dL.Serum calcium, phosphorus, and magnesium were 9.4, 3.6, and 2.1 mg/dl, respectively.Serum sodium concentration was 115 mmol/l, and serum potassium was 3.1 mmol/l; hemoglobin was 12.3 g/ dl, total leukocyte count 10.6 10 9 /L, and platelet count 217 10 9 /L.Aspartate aminotransferase was 130 IU/L, alanine aminotransferase was 136 IU/L, and serum albumin was 3.8 g/dl.HbA1C was 6.3%.Urinalysis showed urate crystals (+ +), 8-10 red blood cells, and 20-25 pus cells/ high power field.Renal ultrasounds revealed kidneys of normal size, bilateral hyperechogenicity and no kidney stones.Eye fundus examination was unremarkable.Viral markers revealed HCV-Ab positivity, while ANCA C and P, ANA, and rheumatoid factor were absent.