Muscle & nerve
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Comparative Study
Sympathetic skin response in diabetic peripheral neuropathy.
There were 72 diabetic patients with clinical evidence of sensorimotor peripheral neuropathy investigated to determine the sensitivity of the sympathetic skin response test (SSR) for detection of sudomotor dysfunction and its correlation with other autonomic function tests, autonomic symptoms, and degree of peripheral neuropathy. Nerve conduction velocities (NCV) were abnormal in all patients, SSR was absent in 60 of 72 patients (83%), Valsalva test was abnormal in 32 of 67 patients (48%) who had the test, and 6 of 72 (9%) had orthostatic hypotension. Statistically significant correlation was found between the Valsalva test abnormality, the degree of peripheral neuropathy, and the SSR in our patients. ⋯ Most patients had one or more autonomic signs or symptoms. Orthostatic dizziness only correlated with SSR, however. These results suggest that sudomotor activity detected by sympathetic skin response is a valuable test for investigation of dysautonomia in diabetic peripheral neuropathy.
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The sympathetic skin response (SSR) was studied in 47 diabetic patients selected for the presence of symptoms and clinical signs of peripheral neuropathy and in 24 normal control subjects. The SSR was present in all controls but was absent at the foot in 66% and at the hand in 27.7% of the diabetic patients. Absence of the SSR failed to correlate with other electrophysiologic parameters on routine nerve conduction and electromyographic studies. ⋯ The SSR was frequently absent, at least in the foot, in those patients with abnormal cardiac beat-to-beat variability (expiratory: inspiratory, E:I, ratio) and pupil cycle time (PCT). In addition there was a good correlation between the amplitude of the SSR and the value of the E:I ratio (r = 0.81, P less than 0.001). The SSR may be a valuable adjunct in the assessment of autonomic involvement in diabetic neuropathy, but its sensitivity requires further evaluation.
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We have applied our technique for the measurement of thermal thresholds to 25 patients referred with symptoms and signs of small fiber peripheral neuropathy in whom conventional electrophysiological indices were individually within the range of normal values for our laboratory. Vibration threshold determinations were also within normal range. Significant abnormalities of thermal thresholds were noted in all patients. The results indicate that the technique provides an accurate, easily performed and reproducible index of function in small A delta and C groups of nerve fibers.
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We are reporting five patients who suffered serious injuries from surgery for thoracic outlet syndrome, which has been a controversial subject from many aspects. Many argue that it is much overdiagnosed and overtreated. ⋯ Recently, the use and misuse of electrodiagnostic studies in the diagnosis of disputed thoracic outlet syndrome has been discussed in the literature. The cases that we are reporting are especially tragic because the elective surgeries were performed in patients who had little or no clinical abnormalities on examination prior to the surgery.