Thursday, January 29, 2015
Why does pulmonary fibrosis cause polycythemia?
Polycythemia means too many red blood cells and it is the opposite of anemia. Polycythemia in pulmonary fibrosis is usually due to a low blood oxygen level. If the blood oxygen saturation falls below 90%, then the bone marrow will be stimulated to make more red blood cells resulting in polycythemia.
Patients with chronic lung disease (such as pulmonary fibrosis or emphysema) will develop polycythemia if the blood oxygen level falls to a low level for more than a few minutes per day. When patients with pulmonary fibrosis have polycythemia, it usually means that they need supplemental oxygen or, if they are already on oxygen, they need a higher flow rate of oxygen.
Sometimes, the oxygen level can be normal when patients are awake and resting but the oxygen level can drop either when patients are sleeping or when they are exerting themselves.
James N Allen, Jr, MD
Clinical Professor of Pulmonary, Allergy, Critical Care & Sleep Medicine
College of Medicine
The Ohio State University