ASSESSMENT OF PULMONARY FUNCTION TESTS IN PATIENTS OF HYPOTHYROIDISM AND OF THE EFFECTS OF LEVOTHYROXINE ON THEIR PULMONARY FUNCTION TESTS

BACKGROUND Hypothyroidism is a condition resulting from inadequate thyroid hormone secretion from the thyroid gland due to the structural and functional impairment. Many patients with hypothyroidism present with dyspnoea. Hypothyroidism causes a restrictive pattern of lung disease due to respiratory muscle weakness, hypoxic alveolar hypoventilation and decrease in maximal breathing capacity. Aims and Objectives- The objective of the present study is to evaluate spirometry in patients with hypothyroidism, supplement them with levothyroxine according to protocol and reassess their spirometry after three months and compare the two sets of spirometry parameters. MATERIALS AND METHODS An uncontrolled clinical trial with supplementation of levothyroxine for a period of four and a half months to the newly diagnosed hypothyroid patients was carried between February 2017 and October 2017 in Biochemistry Department and Chest Department in College of Medicine and Sagore Dutta Hospital, Kamarhati. Thirty-two patients with hypothyroidism were followed up till the end. Serum TSH and total T4 levels were measured at the beginning and repeated after six weeks of levothyroxine therapy to normalise the TSH and total T4 levels. Simple spirometry was done at the beginning and repeated after three months of normalisation of TSH level. Height (cm) and weight (kg) of all the participants were noted at the beginning and end. RESULTS The results were analysed by paired t-test and chi-square tests using SPSS version 20. Hypothyroid patients showed a significant increase in FEV1, FVC and FEF 25%-75% after treatment (p < 0.05), but the change in FEV1/FVC ratio was not statistically significant. From eight hypothyroid patients with mild restriction, six changed to normal but one progressed to moderate restriction after treatment. All seven hypothyroid patients with moderate restriction changed to mild restriction (100%). CONCLUSION In conclusion, respiratory system can be affected in a restrictive pattern in hypothyroid patients and most of these are completely reversible with levothyroxine.