Diagnostic yield of clinical, electromyographic and pathologic studies in muscle disorders

Muscle diseases are classified into two major groups, i.e.; myopathic which also includes muscle dystrophies and neurogenic. Investigations of muscle disease include clinical biochemistry, electromyography, muscle and cytogenetics. The aim of our study was to evaluate the diagnostic yield of clinical biochemistry, eletromyographic and pathologic in different muscle disorders-further more to detect the prevalence of different muscle disorders in our locality in a specific period. Sixty patients with generlized hypotonia and hyporeflexia [40 males and 20 with ages ranged from 2 months to 13 years were studied consequatively in addition to 15 healthy controls of matched age and sex for comparison in certain aspects. All cases were subjected to: a] thorough clinical and neurological evaluation, b] assessment of serum creatine kinase, c] electromyography and d] muscle biopsy from the most affected for histologic and histochemical studies. Frequency of muscle disorders was pathologically as: 41.7% in muscle dystrophies, 25% in congenital myopathies 8.3% in inflammatory myopathies and 25% in spinal muscle atrophy. Clinically; muscle dystrophies were found in 41.7%, however with difference in subtypes. Congenital myopathies were suggested in 30% of cases inflammatory myopathies in 8.3% and spinal muscle atrophy in 20% Electromyographic studies were compatible with the pathologic results in all cases of myopathies and spinal muscle atrophy. All cases of muscle dystrophies were evaluated as myopathic disorders. Serum creatine kinase was highly significantly elevated in the group of muscle dystrophies, significantly elevated in inflammatory myopathies and mildly elevated in spinal muscle atrophy as compared with controls. Clinical biochemistry and pathologic compatibility was found in 92% of dystrophinopathies group, 88% of myopathyies and 80% of neurogenic muscle atrophy .Apart from the group of muscle dystrophy, the EMG yield was compatible with the pathologic diagnosis of all cases of myopathies, and neurogenic muscle atrophy. Thus all measures considered concordant in diagnosis of muscle diseases