Distal myopathy

Abstract

Various types of the distal myopathy except Welander's late distal myopathy of Swedish type were described. There were many reports in the past concerning the varieties of the distal myopathy. Distal myopathy is a rather rare disorder and it may be difficult to diagnose these cases. Among these various distal myopathy, an emphasis was made upon the clinical and pathological characteristics of the diseases, particularly distal muscular dystrophy of Miyoshi, Distal myopathy with rimmed vacuole formation of Nonaka and ours, and Oculo-pharyngo-distal myopathy. All these diseases show the distal muscle involvement but the clinical features, heredity, course and pathological features are quite different, and prognosis is also different. Accordingly when we examined these distal myopathy cases, clinical characteristics and histo-pathological findings should be carefully studied. It should be also emphasized that the level of serum CPK dose not indicate the severity of the myopathy. In muscular dystrophy or myositis, serUm CPK elevates remarkably and we can consider the level of CPK as a sign of the severity or condition of the disease. However, in myopathy as "rimmed vacuole distal myopathy" serum CPK remains in normal level even though weakness is severe. This is due to absence of the membrane abnormalities of muscle cells. Leakage of the CPK from muscle cells, therefore, does not reflect the degree of the cell destruction. In this point we have to remember the fact that serum CPK is not a indicator of all muscle diseases and even if the CPK is normal, we have to consider the presence of myopathy.