The Myositis Association defines muscle enzymes as proteins present inside muscle fibers serving a metabolic function. When muscle cells break down, they leak these enzymes into the blood stream. Muscle enzymes are detected in the blood to diagnose a variety of muscular conditions. When patients complain of muscle aches or weakness, the laboratory tests detecting the elevated levels of muscle enzymes are a cornerstone of diagnosis.
Rhabdomyolysis
MedlinePlus notes that serum muscle enzymes can be significantly raised in cases of rhabdomyolysis, a condition where skeletal muscles break down extensively, releasing their enzymatic contents and a pigment called myoglobin into the blood stream. Both the enzymatic proteins and the pigment may block the renal tubules and cause severe kidney damage, leading to acute renal failure. Rhabdomyolysis can be a fatal condition if not treated early by the administration of intravenous fluids in an attempt to flush the myoglobin out of the kidneys.
Myositis
The Myositis Association identifies two types of myositis. Infection and injury of muscles can cause reversible swelling, which results in the release of muscle enzymes into the bloodstream; this is a temporary myositis. A chronic type of myositis caused by a group of diseases called inflammatory myopathies results in permanent swelling of muscle fibers. Inflammatory myopathies are postulated to be due to an immune reaction in which antibodies attack the body's own muscle cells. Inflammatory myopathies generally manifest with fatigue, muscle weakness and muscle aches.
Metabolic Diseases of Muscles
Metabolic diseases of the muscles are another cause for the elevation of muscle enzymes, as noted by the Muscular Dystrophy Association. Metabolic diseases of muscles, called myopathies, are a group of diseases caused by genetic defects that result in a missing enzyme needed for proper muscle functioning or energy production. There are 10 metabolic muscle diseases, and each is given a distinctive name according to the name of the lacking enzyme. Patients suffering from myopathies experience muscle weakness and unusual tiredness, especially during exercise, and are at an increased risk of rhabdomyolysis with overexertion.
