High-voltage injury — dark urine and a tense forearm

The data show three concurrent, time-critical consequences of high-voltage electrical injury. First, rhabdomyolysis: a CK of 24 000 U/L (rhabdomyolysis is defined by a CK above about 1000 U/L) with dark red-brown urine, a positive blood dipstick and no red cells on microscopy is myoglobinuria — the myoglobin is being released from necrosing muscle along the current path. Second, the metabolic consequences of that necrosis: the pH of 7.28 with a base excess of negative 7 is a high-anion-gap lactic acidosis from the injured tissue, and the potassium of 6.1 mmol per litre is released from lysed muscle cells — both predict an evolving acute kidney injury from pigment nephropathy. Third, compartment syndrome: the tensely swollen forearm with severe pain on passive finger extension is the classic clinical picture of a compartment under pressure from deep muscle oedema within a fixed fascial envelope.^[5][7]