Pulmonary function abnormalities in young adults with thalassemia major

Abstract

Thalassemia seems to be the most common genetic disorder. The pathophysiologic mechanisms for lung impairment is not clear. Lung function tests in children showed small airway obstruction and restrictive lung changes. Forty-two patients, 22 females and 20 males, aged from 17 to 36 years old, with homozygous β-thalassemia were examined in a lung function laboratory. All patients received chelation therapy and none of them had history of respiratory disease. Lung function tests included spirometry, static lung volumes measured by a closed circuit helium rebreathing technique and diffusion capacity measured by the method of single breath diffusion of carbon monoxide. All patients, before these tests, had haematologic examinations (Hb, serum ferritin), electrocardiogram and echocardiogram. Only five out of 42 patients had completely normal pulmonary function. Four had only diffusion impairment, 18 restrictive and 15 combined (restrictive and obstructive) pattern of lung disease. Vital capacity (in 27 patients), total lung capacity (in 21 patients) and forced expiratory volume in the first second (in 30 patients) were abnormally reduced. The ratio of residual volume (RV) to total lung capacity (TLC) was increased in 19 patients. Patients with only diffusion impairment had statistically significant more increased serum ferritin value (4415 ng/ml) than other patterns of lung function. Patients with combined or restrictive pattern of lung function, had heart failure and osteoporosis more often than other patients. Heart failure and the aberrant growth process that limits the volume of peripheral airspace are perhaps the possible mechanisms for the restrictive lung disease, small airways obstruction and hyperinflation.