Myoglobinuria

Myoglobinuria
Urine from a person with rhabdomyolysis showing the characteristic brown discoloration as a result of myoglobinuria
Classification and external resources
ICD-10	R82.1
ICD-9	791.3
DiseasesDB	23059
eMedicine	ped/1535
Patient UK	Myoglobinuria
MeSH	D009212

Model of helical domains in myoglobin.

Myoglobinuria is the presence of myoglobin in the urine, usually associated with rhabdomyolysis or muscle destruction. Myoglobin is present in muscle cells as a reserve of oxygen.

Causes

Trauma, vascular problems, venoms, malignant hyperthermia, certain drugs and other situations can destroy or damage the muscle, releasing myoglobin to the circulation and thus to the kidneys.

Under ideal situations myoglobin will be filtered and excreted with the urine, but if too much myoglobin is released into the circulation or in case of renal problems, it can occlude the renal filtration system leading to acute tubular necrosis and acute renal insufficiency.

Other causes of myoglobinuria include:

• McArdle's disease
• Phosphofructokinase deficiency^[1]
• Carnitine palmitoyltransferase II deficiency
• malignant hyperthermia
• Polymyositis

Diagnosis

After centrifuging, the urine of myoglobinuria is clear, where the serum of hemoglobinuria after centrifuge is pink to red.

Treatment

Hospitalization and IV hydration should be the first step in any patient suspected of having myoglobinuria or rhabdomyolysis. The goal is to induce a brisk diuresis to prevent myoglobin precipitation and deposition, which can cause acute kidney injury. Mannitol can be added to assist with diuresis. Adding sodium bicarbonate to the IV fluids will cause alkalinzation of the urine, believed to reduce the breakdown of myoglobin into its nephrotoxic metabolites, thus preventing renal damage. Often, IV normal saline is all that is needed to induce diuresis and alkalinize the urine.

External links

• Overview on the Neuromuscular disease center website.

References