A STUDY OF PREVALENCE OF AUTONOMIC DYSFUNCTION IN TYPE-2 DIABETES MELLITUS IN A TERTIARY CARE CENTER

BACKGROUND Diabetes Mellitus, a disease characterized by hyperglycaemia caused by absolute or relative deficiency of insulin. The persistent hyperglycaemia causes a diverse functional and morphological alterations which affect almost all systems of the body. Although diabetic retinopathy, nephropathy and neuropathy are well known, autonomic neuropathy is the most neglected aspect of diabetic late complications due to difficulties in diagnosis, which requires invasive investigations in earlier days, and lack of specific treatment. This study has been conducted on the prevalence of autonomic dysfunction in Type II diabetes mellitus patients and the association of various factors with this disease in the diabetic population in and around Thanjavur. Aims and objective of the study - 1) To study the prevalence of autonomic neuropathy in previously diagnosed and newly detected patients with Type 2 diabetes mellitus in Thanjavur. 2) To analyse the involvement of parasympathetic and sympathetic system in Type 2 Diabetes mellitus Patients with autonomic nervous system damage. 3) To find the correlation between autonomic impairment and proteinuria. 4) To establish the efficacy of the squatting test as an early marker of autonomic impairment. MATERIALS AND METHODS This is a prospective study and all the patients were admitted in Thanjavur medical college hospital and studied as in-patients. This study comprises of 40 Type 2 diabetes mellitus patients (26 males and 14 females). 10 healthy volunteers (relatives of patients), 6 males and 4 females were studied for age and sex matched control. The study duration is from January 2015 to August 2015 for a period of 8 months. The age range of study population varies from 40 years to 79 years. The duration of diabetes of the population studied ranges from 0 to 20 years. Newly detected as well as known diabetic patients were included in the study. By means of structured questionnaire, dizziness/vertigo/postural instability on standing, Regional hypohidrosis/hyperhidrosis, Dysphagia/vomiting/post-prandial gastric fullness/ nocturnal diarrhoea, diminished bladder sensation/decreased frequency of micturition, hesitation and weakness of urinary stream / urinary incontinence, impotence in males, tingling and numbness of extremities were asked aimed at assessing the presence of symptoms of autonomic neuropathy. Symptomatic autonomic neuropathy was considered to be present if one or more symptoms are present. Seven cardiovascular autonomic tests were done to assess both sympathetic and parasympathetic function. Four tests evaluating parasympathetic, two tests evaluating sympathetic and one test evaluating both parasympathetic and sympathetic function. These tests are deep breathing test, heart rate response to standing, Valsalva manoeuvre, intravenous atropine, standing, sustained hand grip and squatting test. All ECGs were recorded in BPL Cardiart 108T/MK-vl ECG machine. Resting tachycardia and BMI are included in this study. The following are the biochemical tests such as Fasting Blood Sugar, Post Prandial Blood Sugar 2 hr after 75 gm of glucose load, Blood Urea, Serum Creatinine and 24 hrs Urinary Protein were done in the patients. Statistical association was calculated by using Chi-Square test. RESULTS 90% of patients studied had prevalence of diabetic autonomic neuropathy. Parasympathetic involvement was seen in 82.5% of patients while sympathetic involvement was seen in 37.5%. Nocturnal diarrhoea and urinary symptoms had the greatest correlation with the severity of autonomic impairment. Among the tests performed, the heart rate response to deep breathing and to postural change from lying to standing were found to be the most sensitive in detecting prevalence of autonomic neuropathy. The squatting test may be used as an early marker of prevalence of subtle autonomic impairment, even in asymptomatic diabetics. CONCLUSION This study revealed a high prevalence of autonomic neuropathy in Type-2 diabetes mellitus patients. This was evident even in asymptomatic patients. The squatting test can be used as an early marker of dysautonomia. The degree of metabolic control was the factor which had the strongest association with severity of autonomic impairment. Thus, this study underscores the value of tight metabolic control in the ideal management of Type-2 diabetes mellitus