Myoglobin is the oxygen trapping protein in muscle. Its higher affinity for oxygen compared with haemoglobin facilitates the uptake of oxygen by muscle cells. When muscles are damaged eg trauma or myositis, myoglobin is released into the circulation. It is filtered by the kidneys and causes acute renal failure either by obstruction of the renal tubules or a direct toxic effect. A particular feature of myoglobin-induced renal failure is hyperkalaemia as a result of the potassium released from the muscle cells on top of the hyperkalaemia of renal failure.
Treatment is based on maintaining a high fluid intake, while urine output is present. Bicarbonate, through maintenance of an alkaline urine may also help prevent renal failure.
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