MAKE YOUR DIAGNOSIS The Case | Idiopathic hypocomplementemic interstitial nephritis

A 70-year-old male with chronic kidney disease stage 3 developed increasing peripheral edema and a progressive renal insufficiency over 6 months. This was associated with hypertension (168/98mmHg) and hematoproteinuria (urine protein creatinine ratio of 381mg/g). The serum creatinine reached a peak of 3.3mg/dl. There was no history of weight loss, fever, or infections. He did not have any history of skin rashes, arthralgia, or hair loss. There was no evidence of any exposure to non-steroidal anti-inflammatory drugs, herbal medicines, or over-the-counter medications. Physical examination was unremarkable, except for the presence of bilateral leg edema. Similarly there was no evidence of skin rashes, arthropathies, or lymphadenopathy. There was a past medical history of two similar episodes over the last 3 years.