Thalassemia: Lung Function with Reference to Iron Studies and Reactive Oxidant Status

Abstract

Pulmonary function tests were performed in 15 thalassemic patients (age 5 years 8 months to 18 years 6 months), receiving both regular transfusions and desferrioxamine, to determine the presence and nature of any abnormalities in lung function. Reactive oxidant production from neutrophils was measured simultaneously to ascertain if a causal relationship existed between free radical production and tissue damage in the lungs. Mean total lung capacity, mean residual volume, and mean forced vital capacity were significantly reduced, indicating a restrictive pattern of lung function abnormality. In addition, the carbon monoxide diffusion was low, and hypoxemia was present in 6 of 13 patients tested. These pulmonary function abnormalities did not correlate with age, cumulative volume of transfusion, or serum ferritin levels. In addition, neutrophil reactive oxidant status did not correlate with these or with pulmonary function parameters. These results indicate that neutrophil-derived oxygen free radicals do not appear to be a major cause of lung function abnormalities in thalassemics.

Comparison of pulmonary functions of thalassemic and of healthy children

“…Among the thalassemic subjects, restrictive lung function abnormality was the most common (42/63) observation documented in this study. Our findings are consistent with those of Carnelli et al, 1 Factor et al, 2 Tai et al, 5 Luyt et al, 6 and Filosa et al 7 What is unique to our study is that it was performed exclusively in children, while those studies mentioned earlier were all performed in both children and adults, with a considerably older mean age. Therefore, our study shows that lung dysfunction in thalassemic patients has occurred since childhood.…”

“…There was no correlation between percentage from predicted forced vital capacity and serum ferritin levels, whether in male (r=0.191; P=0.967) or female (r =-0.076, P=0.695) thalassemic subjects. Keywords: pulmonary function, thalassemia, spirometry, serum ferritin level, restrictive lung dysfunction T halassemia refers to a heterogeneous group of heritable hypochromic anemias of various degrees of severity; [1][2][3][4][5][6][7][8][9] it is considered to be the most prevalent genetic disorder in the world. 3 Transfusions of 15-20 ml/kg of packed cells are usually required every 4-5 weeks.…”

The hypercoagulable state in thalassemia

“…4 The presence of a persistent hypercoagulable state combined with the infrequent occurrence of significant thrombotic events suggests that thrombosis is largely a subclinical process in thalassemia and has been associated with autopsy findings of platelet and fibrin thrombi in the microvasculature in the lungs and the brain. 20,21 These thrombi could contribute to the pulmonary hypertension, low lung capacity, hypoxemia, and diffusion defects associated with right heart failure (cor pulmonale) [22][23][24][25][26][27] and to the high frequency of ischemic brain lesions associated with asymptomatic brain damage as detected by MRI. 14 Several etiologic factors may play a role in the pathogenesis of the hypercoagulable state in thalassemia.…”

“…22 In another study of 15 thalassemic patients, the mean total lung capacity, mean residual volume, and mean forced vital capacity were significantly reduced. 23 In addition, the DLCO was low, and hypoxemia was present in 6 of 13 patients tested. 23 These findings suggest that the early right ventricular dysfunction, which precedes left heart failure in many patients with ␤-TM and ␤-TI, may be due to pulmonary hypertension and not cardiomyopathy resulting from excessive iron deposition.…”

“…23 In addition, the DLCO was low, and hypoxemia was present in 6 of 13 patients tested. 23 These findings suggest that the early right ventricular dysfunction, which precedes left heart failure in many patients with ␤-TM and ␤-TI, may be due to pulmonary hypertension and not cardiomyopathy resulting from excessive iron deposition. 24,25 In support of this idea, a Doppler echocardiography study in which pulmonary artery pressure was measured in 33 patients with ␤-TM (aged 2-24 years) showed that 28 patients had evidence of pulmonary hypertension.…”