Muscular dystrophies of childhood.

This review article on the muscular dystrophies of childhood has a bibliography of 62 references. The conditions dealt with are Duchenne-type muscular dystrophy, late onset X-linked recessive muscular dystrophy, congenital muscular dystrophy, limb-girdle muscular dystrophy, facioscapulo-humeral muscular dystrophy, ocular muscular dystrophy, myoclonic muscular dystrophy, and distal muscular dystrophy. Clinical examination and functional capacity are emphasized. The latter is graded on a scale of one to nine, varying from 1) walking and climbing stairs without assistance to 9) wheel-chair or bed, can perform only limited activities with lower arm and hand muscles. Laboratory examination, especially of creatine phosphokinase, muscle biopsy and electromyography are very important in diagnosis. Generally speaking, there is no specific treatment for muscular dystrophy. Myotonic dystrophy is an exception. There is evidence that an unstable muscle membrane is at fault in this condition and several drugs that are so-called 'membrane stabilizers' have been utilized in the treatment of myotonus. These include quinine, quinidine, procainamide and phenytoin. The authors consider phenytoin to be the most useful. It may act by stabilization of sodium conductance or stimulation of the Na⁺-K⁺ adenosine triphosphatase system. Since Duchenne-type muscular dystrophy (DMD) is the most important of the various dystrophies, discussion of this condition, its diagnosis, and management is extensive. It is transmitted as an X-linked recessive trait, transmitted by a mother to her sons and the carrier state to her daughters. Thus, 50% of the carrier's daughters will be carriers and 50% of her sons will be affected. Consequently, a diagnosis of DMD carries grave implications to the patient and a great burden to the family. The diagnosis should not be considered as definite until satisfactory criteria have been met. There will be no family history in one third or more of the patients; these cases are thought to be mutations. Once the diagnosis is established, discussion with the parents should be complete and frank. It is usually initially best not to include the child in discussion of expected disability and life expectancy. In management, active exercise should be maintained as long as possible. Overweight is to be avoided. Contractures should be avoided by exercise as long as possible. If contractures are serious tenotomy will be necessary. General anesthesia must be avoided if at all possible. Scoliosis is usually progressive and difficult to control. Respiratory compromise is a serious complication as pneumonia is the most frequent cause of death. Cardiovascular complications are not usually serious in the earlier stages of DMD although electrocardiac changes are often present. However, in later stages congestive heart failure is more common and becomes the chief cause of death. Emotional and behavioral problems are common and the frequent intellectual retardation in the muscular dystrophies increases the problems of management. As the disease progresses, the increasing dependency of the patient makes for manipulative behavior. The goal of treatment should be to prevent family deterioration and to encourage the patient to maintain maximal levels of activity. This well organized and concise article is important to everyone interested in the muscular dystrophies and the problems of their classification, diagnosis and management. (Voris - Chicago, Ill.)