Myoglobin Cast Nephropathy, A Series of Five Cases

Abstract

Acute kidney injury is a potential complication of severe rhabdomyolysis, which occur mostly due to excessive release of myoglobin from necrosed muscle cells. The major causes of rhabdomyolysis in Indian subcontinent include wasp sting, snake envenomation, strenuous exercise and seizures, etc. The main pathophysiology of AKI due to tubular obstruction, renal vasoconstriction and tubular damage due to myoglobin casts in the tubular lumen. With raised serum creatinine level these patients also show remarkably high serum creatine phosphokinase (CPK). On light microscopy myoglobin casts present as granular eosinophilic pigment casts, sometimes may mimic haemoglobin casts or bile casts. To differentiate the myoglobin casts from other, immunohistochemistry for myoglobin is used in most of the centers worldwide now days. A good number of patients need haemodialysis and most of them recover well, however early diagnosis and timely intervention is warranted. Here we report five cases of myoglobin cast nephropathy in a year at department of histopathology, Armed Forces Institute of Pathology (AFIP), Dhaka, following different non traumatic causes, diagnosed by immunohistochemistry for myoglobin.