(See also Overview of Idiopathic Interstitial Pneumonias.)
Acute interstitial pneumonia causes the same type of symptoms as the acute respiratory distress syndrome. It tends to affect healthy men and women who are usually older than 40.
Fever, cough, and difficulty breathing develop over 1 to 2 weeks, typically progressing to acute respiratory failure.
The diagnosis is confirmed when other causes of acute lung injury are excluded and consistent findings are found with computed tomography (CT) and lung biopsy, if done.
Treatment aims to keep the person alive until the disorder resolves. Mechanical ventilation is needed if there is respiratory failure. Corticosteroids are generally used, but it is not clear whether they are effective.
More than 60% of affected people die within 6 months, usually as a result of respiratory failure. In people who survive, lung function usually improves with time. However, the disease may recur.