Myopathy Definition
The word myopathy literally means muscle disease. "Myo" is from the Greek word for muscle, while "pathy" is Greek for "suffering". More specifically, myopathies are neuromuscular conditions wherein the muscle fibers are damaged and no longer function for a number of reasons, thus resulting in muscular weakness. Myopathy implies a primary defect in the muscle. Even mild muscle complaints, such as cramps, stiffness, and spasms are, in fact, associated with this disorder. Myopathy is a very broad term. Specific classes are available with more distinct classifications. Some of these classes are dystrophies, myotonia, neuromyotonia, mitochondrial myopathies, and familial periodic paralysis, among others.
Myopathy Diagnosis
Myopathy can be determined in any one of a number of lab studies - including screening for CK with isoenzymes, electrolytes, calcium, magnesium, serum myoglobin, serum creatinine and BUN. Other tests include a urinalysis to determine myoglobinuria, complete blood count, erythrocyte sedimentation rate, thyroid function tests, and AST.
Myopathy Treatment
Severe myopathies often require emergency medical care. Patients suffering from rhabdomyolysis need immediate critical care and must be admitted to treat life-threatening complications. Patients suffering from hypokalemic periodic paralysis usually require intravenous or oral potassium replacement. For patients with hyperkalemic periodic paralysis, however, attacks are often so brief that no therapy is necessary.
Myopathy Symptoms and Signs
While myopathy comes in various distinct forms, the most common known symptoms of this muscular disorder are muscle weakness, weakness of the limbs, and weakness after physical exertion. Muscle mass deceptively appears normal, as atrophy occurs very late in muscle disorders. Similarly, deep tendon reflexes (or DTRs) and sensory perception should appear normal. A closer examination of the skin may expose Gottron papules, commonly described as pinkish scaly areas over knuckles, knees, and elbows.
Myopathy Causes
Idiopathic myopathies are mostly immunological in origin. Some are correlated with connective tissue disease. Acute alcoholic myopathy is possible in patients who experience extreme muscle pain and limb weakness after drinking huge amounts of alcohol. Myopathy may also have infectious origins, including trichinosis, cysticercosis, toxoplasmosis, HIV, influenza, and lyme disease. Endocrine myopathy may result from Addison disease, Cushing's, hyperthyroidism, hypothyroidism, or hyperparathyroidism. Some forms of myopathy are also caused by drug ingestion or high toxic absorption. Steroids in prolonged doses, AZT, Lovastatin, Cocaine, Colchicine, and Amiodarone are some of the most common causes.
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