Children at High Altitude: Pulmonary and Renal Abnormalities.

• At elevations above 10,000 feet alveolar hypoxia leads to pulmonary arterial hypertension, arterial hypoxemia, and secondary polycythemia in most persons.' The adjustments of adults to this hypoxic environment have been extensively studied but there is relatively little information pertaining to neonates and young children. The only published catheterization study on young children at high altitude is that of Penaloza et al. who reported that in seven infants the average pulmonary arterial pressure was greater than that found in older children or adults. The studies to be described below reveal anatomical abnormalities of the pulmonary vasculature and renal glomeruli in children reared at high altitudes, thus providing an anatomical basis for the pulmonary hypertension observed by Penaloza.