Radiological distribution of pulmonary emphysema. Clinical and physiological features of patients with emphysema of upper or lower zones of lungs.

, , 81-89. Pulmonary emphysema exists in two main pathological forms, centrilobular and panlobular (panacinar) emphysema, the lesions predominantly affecting the upper and lower zones of the lungs respectively. There is disagreement among authors as to the clinical and physiological differences between these two forms, and direct evidence of the pathological type is seldom available during life. Patients with emphysema can, however, be divided on radiological criteria into an upper zone' and a lower zone' group, and it can be argued that these groups relate respectively to the centrilobular and panlobular forms of the disease. The evidence is far from conclusive but it was thought that a comparison of the two radiological groups would be of value. Patients in whom there was no obvious zonal preponderance were not included in the study. Fifty patients with definite radiological evidence of pulmonary emphysema have been studied, those with α-antitrypsin deficiency being excluded. Thirty-one patients (62%) had emphysema which predominantly affected the upper zones of the lungs; the lower zones were the more severely affected in the remainder. Bullae were found in approximately equal proportions in each group. All the patients were, or had been, cigarette smokers. There was no significant difference between the mean ages of the two groups; only seven patients were free from exertional dyspnoea, all being in the upper zone group. Chronic bronchitis occurred with equal frequency in the two groups but started on average about 10 years earlier in those with lower zone disease; the latter patients had rather more severe airflow obstruction and more severe blood-gas abnormalities. The presence or absence of chronic bronchitis per se, however, did not appear to have any significant effect upon the common respiratory function tests. No data emerged from this study which suggested that there were differing aetiological factors in the two groups.