Characterictics of changes of breathing mechanics and gas exchange conditions in pulmonary histiocytosis X patients

Abstract

Seventy cases of verified pulmonary histiocytosis X (HX) were analysed retrospectively. The patients’ age ranged from 13 to 52 years. There were examined 62 males and 8 females. Standard examination included determination of total and vital capacities (TLC and VC), residual volume (RV), RV/TLC ratio, parameters of forced expiratory maneuver (FEV₁, PEF, MEF _25,50,75 and FEV₁/VC), the aurway resistance (Raw) and diffusion capacity for carbon monoxide using both the single-breath (TOO) and steady-state (DCO) methods. A very few patients (frequency 0.03) had entirely normal test results. RV and RV/TLC indices were increased in 0.71 patients, TOO and DCO indices were decreased in moderate to severe degree in 0.70 patients. Moderate to severe airflow limitation was found in 50% of cases with various TLC and RV/TLC values and with decrease of TCO and DCO in the most of cases (0.86). There was a great variety of measured parameters combinations, such as obstructive, restrictive or mixed patterns. The type and degree of lung function abnormalities varied according to the extent of the granulomatous affection and cysts and bullae formation. As more the fibrosis has progressed, TCO and DCO indices have been decreased. However, as cysts and bullae have been formed, RVДLC ratio has been increased without airflow limitation. Therefore, there were no consistent changes in lung function measurement in pulmonary histiocytosis X patients, but decreased TCO and DCO values without airflow limitation were correlated to the granulomatous fibrosis and the airflow limitation was correlated to the bullous formation. In other cases the TLC decrease evidences the exhaustion of compensatory possibilities of active-functioning pulmonary surface.