Acute interstitial pneumonia (also called accelerated interstitial pneumonia or Hamman-Rich syndrome) is an idiopathic interstitial pneumonia (see Overview of Idiopathic Interstitial Pneumonias) that develops suddenly and is severe.
Acute interstitial pneumonia causes the same type of symptoms as the acute respiratory distress syndrome (see Acute Respiratory Distress Syndrome (ARDS)). 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.
When possible, the diagnosis is confirmed with computed tomography (CT), lung biopsy, and pulmonary function tests (see Pulmonary Function Testing (PFT)).
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 from respiratory failure. In people who survive, lung function usually improves with time. However, the disease may recur.
Last full review/revision October 2013 by Harold R. Collard, MD