Estudo de condução nervosa dos nervos sural dorsal e plantar medial no diagnóstico precoce de neuropatia diabética

Abstract

The number of diabetic patients is increasing due to the growth and aging population, greater urbanization, the increasing prevalence of obesity and sedentary lifestyle. Diabetic neuropathy is the most common and troublesome complication of diabetes mellitus, involving about half of patients, leading to high morbidity and mortality. The early detection and identification of neuropathic process could reduce morbidity and disability. In diabetic neuropathy, the most distal sensory fibers of the feet are often affected first; however, they are not evaluated in routine electrophysiological examination, which involves conduction study of the nerves sural, superficial peroneal, tibial and fibular. It is estimated that the sensory nerves dorsal sural and medial plantar, more distal, may be more sensitive in the early detection of diabetic neuropathy more prevalent. Electromyography (electrophysiological study) measures the ability of peripheral nerve to conduct electrical signals, and is abnormal when pathological changes are present in the myelin, nodes of Ranvier or axons. The aim of our study was to evaluate the use of electrophysiological study with study of the distal nerves for early diagnosis of diabetic neuropathy. The study is cross-sectional in outpatients diagnosed with type 2 diabetes and sensory complaints in the lower limbs and in healthy controls. The essential parameters assessed by electromyography were latency, amplitude and speed of electrical responses. The sample included 64 subjects aged 70 years or younger, and 37 had been diagnosed with diabetes and 27 formed the group not exposed. Diabetics subjects also underwent clinical batteries of Michigan and Toronto and the questionnaire of autonomic symptoms. For analysis of the results was performed analysis of covariance and Spearman ordinal correlation. They were considered statistically significant tests with probability value <0.05. No cases of neuropathy was identified by the score of Michigan; six (16.2%) were classified as positive for neuropathy according to electromyography with conventional protocol, 18 (48.6%) cases of neuropathy identified by the score of Toronto and 22 (59.5%) were identified by electromyography with specific protocol for distal nerves. We conclude that electromyography with study of distal nerves dorsal sural and medial plantar showed earlier alterations nerve conduction in subjects with type 2 diabetes and sensory complaints.