Myoglobinuria
Myoglobinuria Causes
Myoglobinuria typically results from a number of factors ? including venom absorption, trauma, vascular problems, drug ingestion, and other scenarios which can damage or destroy the muscle. In these situations, the body reacts by releasing myoglobin to the circulation, thus consequently reaching the kidneys. Under ideal conditions, the myoglobin may be filtered and excreted through the urine. However, if an excessive amount of myoglobin is released, it can damage the renal filtration system, eventually leading to acute tubular necrosis and acute renal insufficiency.
Myoglobinuria Definition
The presence of myoglobin in the urine results in a condition known as myoglobinuria, and is usually correlated with rhabdomyolysis or muscle destruction. Myoglobin is the red pigment of muscle cells which serve as an oxygen reserve.
Myoglobinuria Diagnosis
The most important diagnostic tool to determine myoglobinuria is a lab test to measure CK levels to assess for rhabdomyolysis or muscle damage. While myoglobin levels are the first to increase, the enzyme rapidly returns to normal because they are excreted through the urine. Blood CK levels, on the other hand, may remain high after urine tests for myoglobin turn out negative. Serum CK levels increase within 3 days after the onset of symptoms, and remain high for several days after. Thus, it is a more useful marker of rhabdomyolysis.
Myoglobinuria Symptoms and Signs
Dark urine, usually described as burgundy in color, is indicative of myoglobinuria. Additionally, patients experience severe pain and tenderness or weakness in the affected muscles. Also, decreased urine output and rapid weight gain may also result due to renal failure.
Myoglobinuria Treatment
Patients with myoglobinuria must be admitted for management of complications and IV hydration. A brisk diuresis may be induced to prevent myoglobin influx in the urine. Saline is administered to prevent acute renal failure. Sodium bicarbonate and fluids are administered to raise the pH of the urine to 6.5. To avoid dialysis, diuresis must be safely facilitated by nephrologists. If dialysis is required, a reliable nephrologist should provide immediate consultation. Surgical intervention becomes necessary if the extent of muscle damage is severe. To treat compartment compression syndrome, fasciotomy may be used.