Early detection of central nervous system involvement in hypothyroidism by electrophysiological study

Jayanthi, M (2013) Early detection of central nervous system involvement in hypothyroidism by electrophysiological study. Masters thesis, Thanjavur Medical College, Thanjavur.


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INTRODUCTION: Hypothyroidism is one of the most common endocrine disorders, affecting over one percent of the general population and about 5 percent of individuals over age of 60 years. It is a syndrome characterised by the clinical and biochemical manifestation of thyroid hormone deficiency in the target tissue. Iodine deficiency remains the most common cause of hypothyroidism worldwide. In areas of iodine sufficiency, autoimmune disease (Hashimotos thyroiditis) and iatrogenic causes (treatment for hypothyroidism) are most common. AIM AND OBJECTIVES: 1. This study was undertaken to compare electrophysiological parameters between hypothyroid patients and control. 2. To evaluate functional changes in nervous system in hypothyroidism by different electrophysiological parameters like visual evoked potential, Brain stem auditory evoked potential, Somatosensory evoked potential. MATERIALS AND METHODS: This study was conducted in the Department of Physiology, Thanjavur Medical College & hospital, Thanjavur. Case control type of study was done. The study period extended between may 2011 to 2012. The patients were selected from medicine and surgery department. Out of 40 subjects, 7 males and 33 females with Hypothyroidism of age group (17-64 years) were selected. Diagnosis of hypothyroidism was confirmed when the total thyroxine level was below 4μg/dl and the thyrotropin level was above 4.5mU/ml. A history was taken, and a complete medical examination and neurological examination were out for every patient. Out of 40 controls, 10 males, 30 females, of age group (17-64 years) were selected. Inclusion criteria: • Patients with biochemical evidence of hypothyroidism (Serum total thyroxine < 4μg/dl, TSH > 4.5mU/ml. Exclusion criteria: • Diabetes mellitus. • Neurological disorders. • Psychiatric illness. • Seizures. • Hypertension. • Eye diseases (severe myopia, cataract, glaucoma etc). • Collagen disease. • Renal impairment. • Drug abuse. RESULTS: Out of 80 subjects, 40 were hypothyroid patients forming the study group and remaining 40 were normal subjects forming control group. In this study hypothyroid patients who form the study group were in age group 17-64 years, mean 39.64 and the subjects in control groups were in the age group 17-64 years, mean 35.75. The mean values and their standard deviation for the control group and the study group of hypothyroids were tabulated. The two groups differ significantly in various electrophysiological parameters like VEP, BAEP, and SSEP. ’P’ value was derived from data analysis by using statistical package SPSS version 18 and statistical analysis was done by student ‘t’ test. The statistical significance was considered at p value < 0.05. CONCLUSION: The result of present study shows that there is involvement of Central Nervous System in hypothyroidism. The hypothyroid patients show prolongation of latency in electrophysiological studies. Electrophysiological parameters like P100 latency of VEP, latency and inter peak latencies of I-III, III-V, I-V of BAEP and peripheral and cortical latencies of SSEP of median nerve were evaluated. The observation shows prolongation of latencies suggestive of central nervous system involvement in hypothyroidism. This study suggests that periodic evaluation of hypothyroid patients to electrophysiological test will help in monitoring the progress of neuropathy and earlier detection of nervous system involvement to reduce the morbidity of hypothyroid patients. However further studies are required to evaluate the correlation between the electrophysiological parameters and thyrotropin (TSH) level and duration of disease so that preventive measures can be suggested to prevent the central nervous system involvement.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Early detection ; central nervous system involvement ; hypothyroidism ; electrophysiological study.
Subjects: MEDICAL > Physiology
Depositing User: Punitha K
Date Deposited: 16 Jun 2018 01:57
Last Modified: 17 Jun 2018 02:57
URI: http://repository-tnmgrmu.ac.in/id/eprint/8508

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