ABSTRACT
This study was designed in order to assess impairment of pulmonary functions tests [PFT] in patients with hypothyroidism to know if they are obstructive or restrictive ones. Forty female hypothyroid patients selected from the endocrine Outpatient Clinic in Kasr El-Aini Hospital were studied. Twenty normal subjects served as the control group. Serum free T3, free T4 and TSH were measured in all subjects to confirm or exclude hypothyroidism. All subjects were subjected to PFT using the microspiro-HI-SO1. PFT included: Vital capacity [VC], forced vital capacity [FVC], forced expiratory volume-1 [FEV1], peak expiratory flow rate [PEFR], forced expiratory flow 25%, 50% and 75% forced expiratory flow 25-75% and maximum voluntary ventilation [MVV]. The results revealed restrictive lung functions in hypothyroid patients in the form of significant decrease in VC%, FVC%, FEVl and MVV% in association with normal FEV1/FVC% in both controlled and uncontrolled hypothyroid. There was significant decrease in PEFR%, FEF25% and FEF25-75% in uncontrolled hypothyroid compared to normal. There was significant negative correlation between TSH and FVC% [r = 0.4 and p = 0.01], FEV1% [r = -0.4 and p = 0.01], PEFR% [r = -0.3 and p = 0.04] and MVV%, [r = -0.4 and p = 0.01]. it was concluded that hypothyroidism causes a predominant restrictive pattern of ventilatory dysfunction, but mixed pattern might occur. These abnormalities in ventilatory dysfunction ameliorated with thyroxin replacement and controlling hypothyroid state