Hypokalemia-associated weakness does not usually become problematic until potassium levels fall toward and then below 1.5 mEq/L, with mild weakness, fatigue, and muscle cramping giving way to severe and generalized…
Serum creatine kinase (CK) is mildly to, at most, moderately elevated (<10 times normal). Electromyography (EMG) discloses fibrillation potentials and a mixed population of motor unit potentials (MUPs): low-amplitude myopathic…
Pathogenesis of Dermatomyositis. A striking feature observed in muscle biopsies taken from patients with DM is the presence of a diverse collection of cell types: CD4+ T lymphocytes, B lymphocytes,…
Because malignancy may be associated with PM (up to 10% of patients), and especially with DM (up to 25% of patients older than 40 years), screening for cancer (carcinomas of…
The prevalence of PM/DM is 1 per 100,000 adults, with a female to male ratio of 2 : 1; there is also a childhood form of dermatomyositis. Presenting symptoms include…
FSHD is inherited in an autosomal dominant (AD) fashion with nearly complete penetrance and variable expressivity, with mild and severe cases seen in the same family. It is due to…
DM2 is caused by an expanded cytosine-cytosine-thymine-guanine (CCTG) tetranucleotide repeat expansion located in intron1 of the zinc-finger protein 9 gene (ZNF9 gene) on chromosome 3q21.3. On normal alleles, there are…
Both DM1 and DM2 are characterized by skeletal muscle weakness and myotonia with additional multisystem involvement. DM1 commonly presents in adolescence and early adult life, as well as a severe…
TREATMENT Goals of therapy in DMD/BMD are to maintain function, prevent contractures, and provide psychologic support. Physical therapy utilizes passive stretching exercises to prevent contractures of the iliotibial band, the…
MANIFESTING DMD/BMD CARRIER FEMALES The vast majority of DMD/BMD carriers, 76% and 81%, respectively, are usually free of symptoms. Mild calf hypertrophy may be seen. However, approximately 8% to 19%…
