In medicine, a myopathy is a neuromuscular disease in which the muscle fibers do not function for any one of many reasons, resulting in muscular weakness. "Myopathy" simply means muscle disease (myo- Greek μυσ "muscle" + -pathy Greek "suffering"). This meaning implies that the primary defect is within the muscle, as opposed to the nerves ("neuropathies" or "neurogenic" disorders) or elsewhere (e.g., the brain etc.). Muscle cramps, stiffness, and spasm can also be associated with myopathy.
Because myopathy is such a general term, there are several classes of myopathy.... (ICD-10 codes are provided where available.)
(G71.0) Dystrophies (or muscular dystrophies) are a subgroup of myopathies characterized by muscle degeneration and regeneration. Clinically, muscular dystrophies are typically progressive, because the muscles' ability to regenerate is eventually lost, leading to progressive weakness, often leading to use of a wheelchair, and eventually death, usually related to respiratory weakness.
(G71.2) The congenital myopathies do not show evidence for either a progressive dystrophic process (i.e., muscle death) or inflammation, but instead characteristic microscopic changes are seen in association with reduced contractile ability of the muscles. Among others, different congenital myopathies include:
(G71.2) nemaline myopathy (characterized by presence of "nemaline rods" in the muscle),
(G71.2) multi/minicore myopathy (characterized by multiple small "cores" or areas of disruption in the muscle fibers),
A less severe form of centronuclear myopathy that may present itself at birth or in early childhood progresses slowly and is inherited as an autosomal recessive genetic trait.
The least severe of the three forms of centronuclear myopathy first appears during the second and third decades of life and is slowly progressive; it is inherited as an autosomal dominant genetic trait.
Common muscle (R25.2) cramps and (M25.6) stiffness, and (R29.0) tetany
Because different types of myopathies are caused by many different pathways, there is no single treatment for myopathy. Treatments range from treatment of the symptoms to very specific cause-targeting treatments. Drug therapy, physical therapy, bracing for support, surgery, and even acupuncture are current treatments for a variety of myopathies.