Clinico-physio-pathologic studies from the viewpoint of neuromuscular disorders were done in 5 cases of juvenile diabetes mellitus of which ages at the onset of the disease were 13 to 22 years. As regards pathologic studies, the quadriceps muscle and the sural nerve were obtained in each case by means of biopsy. Both conventional histologic and electron microscopic observations were performed.
The results obtained were summarized as follows.
1) These 5 cases showed some abnormalities in all the examinations performed including clinical neurologic examinations, electromyographic studies, examinations of motor nerve conduction velocities, and morphologic observations of the muscle and the nerve.
2) As for neurologic signs, autonomic symptoms were noted without exception, while neither hyporeflexia nor disturbed vibratory sensation which was the main neurological symptom in adult type of diabetes mellitus, was frequently observed.
3) Electromyographically, the result was mixed patterns of neurogenic and myogenic tendencies as the authors had pointed out on the adult type of diabetes mellitus. However there were more myogenic tendencies in the juvenile type than in the adult type.
4) The morphological changes of either the muscle or the nerve were not exactly parallel with the degree of clinical neurological symptoms, though histologic changes were the most remarkable in the case which showed the severest neurological signs of the 5 cases.
5) Principal histologic observations on the quadriceps femoris were individual muscle fibre atrophy, focal degeneration of muscle fibres, hypertrophic or degenerative muscle fibres, central nuclei and marked variations in the diameter of fibres. Pictures of grouping small fibres were noted in 2 out of 5 cases.
6) Electron microscopically the changes in the muscle consisted of thickening of the basement membrane of the interstitial capillary, increase of interfibrillar glycogen granules, degeneration of myofibrils sometimes with complete loss of the normal architecture, vacuole formation between myofibrils and thickening of the limiting membrane of the muscle fibre. Abnormal increase of subsarcolemmal lipopigment, one of the most prominent findings in the adult diabetes, was not markedly observed.
7) No relation between the morphological changes and duration of the disease was noted. Nevertheless, endoneural fibrosis in the sural nerve seemed to be more prominent in the cases of longer durations. It was noteworthy that the case 3 and the case 4, of which the durations of the disease were a few months, showed extensive morphological changes as shown in the table 3 and the table 4.
8) From morphological studies, the authors assumed that in juvenile diabetes mellitus changes of the axon might precede those of the myelin, and vice versa in the adult type.
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