pO2 decreases in all except

Fibrosing alveolitis is a disease of unknown cause mainly involving the gas-exchanging poions of the lungs. It may occur in isolation and be called cryptogenic or idiopathic, in which case the clinical manifestations are mainly respiratory, or it may be associated with other disorders, such as rheumatoid ahritis. The histopathologic abnormalities of the pulmonary tissue are identical in either instance. Other names used for the disease have included usual interstitial pneumonia, desquamative interstitial pneumonia and the Hamman-Rich syndrome; these terms may describe different stages of the same pathologic process. Many authors in Noh America and those in the United Kingdom our the term fibrosing alveolitis when describing chronic interstitial pneumonias. There may be accompanying nonspecific Immunologic abnormalities, which may denote that fibrosing alveolitis is pa of the wide spectrum of diseases known as connective tissue disorders. Recently immune complexes have been found in the lung parenchyma; they probably result in the granulocyte destruction and reticuloendothelial proliferation seen in the acute phase of the disease. There are no specific diagnostic tests for the disease apa from lung biopsy, which can be performed at the time of thoracotomy or transbronchially, with the use of a flexible fibreoptic bronchoscope. Lavaged cells from the alveoli have also been obtained the bronchoscope; in persons with fibrosing alveolitis a high propoion of these cells are neutrophils, and after coicosteroid treatment the propoion decreases. The progress of the disease can be followed by examination of these washings as well as by lung scanning with gallium-67 citrate. Newer methods of treatment using combinations of coicosteroids and immunosuppressant drugs are being evaluated and are initially proving to be successful. Ref Davidson 23rd edition pg 616