IMYOTONIA DYSTROPHICA | it is a hereditary autosomal dominant disease occurring in males in the third decade. The cause is not known but the genetic defect has been located at the long arm of chromosome 19.
CLINICAL FEATURES OF MYOTONIA DYSTROPHICA
Weakness of the muscles of the hand, difficulty in swallowing, sometimes nasal voice may be seen. The hand muscles will be stiff and due to myotonia once the patient holds an object or shakes hand, it is difficult to relax the grip.
On examination the striking feature is wasting of the sternomastoids. The facial muscles and muscles of the hand may be weak. The myotonic muscle may show sustained contraction on direct percussion. Extensor muscles of the neck are not affected. Other features include frontal baldness, cataract, atrophy of the test is, cardiac abnormalities, diabetes mellitus and dementia. Rarely goitre and cardiomyopathy with conduction disturbances may develop.
Electromyography shows typical picture or myotonia in addition to myopathic changes. Blood sugar level is high. Pituitary fossa is small. Serum IgG level is low.
Bad. Anaesthesia is hazardous.