Muscular dystrophies and other myopathies
Congenital hereditary muscular dystrophy
Hereditary progressive muscular dystrophy
- Pelvic muscle weakness and atrophy associated with pseudohypertrophy of the calves. Two basic types are recognized: Duchenne muscular dystrophy (Type I) Synonym: childhood pseudohypertrophic muscular dystrophy with the onset of symptoms between the ages of 3 and 5 years, the patients becoming bedridden by age of 12 and death by age 20 to 25 years. Becker muscular dystrophy (Type II) Synonyms: adult pseudohypertrophic muscular dystrophy mild or benign X-linked recessive muscular dystrophy with onset of symptoms between the ages of 20 and 30 years and relatively normal life expectancy in most cases. Atrophic changes begin in the muscles of the pectoral girdle and trunk and extend to the extremities. As their size increases, the muscles become firm and resilient, but their strength diminishes and, eventually, atrophy ensues. Inability to rise to an upright position without turning to the side, waddling gait, and progressive weakness are the characteristic features. Pseudohypertrophy of the calf muscles is due to fibrous tissue and fat infiltration. Involvement of the heart consists of usually terminal cardiomyopathy. Fasciculation and atrophy of the tongue with dysphagia, dysarthria, and thickened nasal speech are usually associated. Usually mild and static mental retardation occurs in about 30% DMD patients most children having normal, even superior intelligence.
- X-linked recessive muscle disease caused by an inability to synthesize dystrophin, which is involved with maintaining the integrity of the sarcolemma; muscle fibers undergo a process that features degeneration and regeneration; clinical manifestations include proximal weakness in the first few years of life, pseudohypertrophy, cardiomyopathy and an increased incidence of impaired mentation; Becker muscular dystrophy is a closely related condition featuring a later onset of disease (usually adolescence) and a slowly progressive course.
- general term for a group of inherited disorders which are characterized by progressive degeneration of skeletal muscles.
- A progressive disorder involving pelvic and scapular girdle muscles marked by weakness of proximal muscles of hip and shoulder areas with variable psychiatric disorders and occasional mild mental retardation. Type IA (LGMD1A) Synonym: proximal limb-girdle muscular dystrophy type 1A A slowly progressive form of muscular dystrophy affecting the proximal limb muscles but sparing the face. (159000) Type IB (LGMD1B) Synonym: proximal limb-girdle muscular dystrophy type 1B A slowly progressive form of muscular dystrophy differing from LGMD1A by the nasal quality of speech. (OMIM 159001) Type 2 (LGMD2, LGMD2A) Synonyms: Leyden-Mobius syndrome distal muscular dystrophy pelvofemoral muscular dystrophy pelvofemoral syndrome tibial muscular dystrophy Muscular dystrophy involving first the pelvic or, less commonly, shoulder girdle with occasional pseudohypertrophy of the calves with onset usually in childhood but sometimes in later stages of life. Muscle wasting tends to be asymmetric when the upper limbs are first involved. Progression of disease varies with inability to walk usually taking place at about 20 to 30 years of onset. Facial weakness and contractures may occur later. (OMIM 253600) Type 3 (LGMD3, LGMD2B) A slowly progressive form of muscular dystrophy involving the pelvic girdle with onset in the late teens. (OMIM 253601)
Myotonic disorders
Myotonic muscular dystrophy
- autosomal dominant neuromuscular disorder which usually presents in early adulthood, characterized by progressive muscular atrophy (most frequently involving the hands, forearms, and face), myotonia, frontal baldness, lenticular opacities, and testicular atrophy; cardiac conduction abnormalities, diaphragmatic weakness, and mild mental retardation may also occur; congenital myotonic dystrophy is a severe form of this disorder.
Myotonia congenita
- congenital genetic disease characterized by tonic spasm and rigidity of certain muscles when a voluntary movement is attempted; also known as Thomsen's disease.
Myotonic chondrodystrophy
- A syndrome of short stature; generalized myotonia with contractures of major joints, microstomia, and muscle rigidity; ocular anomalies, mainly blepharophimosis; and characteristic facies marked by pinched or frozen smile puckered lips. Some degree of mental retardation occurs in about 25% of patients. The affected children usually appear normal at birth and the symptoms become recognizable at 1 to 3 years of age. Malignant hyperthermia is a potentially lethal hazard during anesthesia.
Drug-induced myotonia
Other specified myotonic disorder
Periodic paralysis
- heterogenous group of inherited disorders characterized by recurring attacks of rapidly progressive flaccid paralysis or myotonia; these conditions have in common a mutation of the gene encoding the alpha subunit of the sodium channel in skeletal muscle; frequently associated with fluctuations in serum potassium levels; periodic paralysis may also occur as a non-familial process secondary to thyrotoxicosis and other conditions.
Toxic myopathy
Myopathy in endocrine diseases classified elsewhere
Symptomatic inflammatory myopathy in diseases classified elsewhere
Other myopathies
Critical illness myopathy
Other myopathies
Myopathy unspecified
- impairment of health or a condition of abnormal functioning of the muscle.
