Respiration in Dystrophia Myotonica

Abstract

Dystrophia myotonica is an uncommon disease characterized by muscular wasting, myotonia, endocrine dysfunction, and cataract. The wasting particularly affects the facial muscles, the sterno-mastoids, the trapezii, and the limb muscles, but it may be generalized and produce marked loss of weight. The abdominal muscles are often slack; the pharynx, the larynx, and the diaphragm may all be affected. Myotonia often precedes the wasting but may be absent in the muscles that have atrophied. Myotonia is produced chiefly by sudden movements and occurs commonly in the muscles of the limbs and of mastication. It is diminished by repetitive movements. It has how-ever been observed in the diaphragm (Benaim and Worster-Drought, 1954). The heart muscle may also be involved. Conduction defects and disturb-ances of rhythm are common (Evans, 1944; Spillane, 1951; Fisch, 1951), and sudden death has