Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
Acute Interstitial Pneumonia
Acute interstitial pneumonia (AIP) is a severe acute disease of unknown etiology that usually occurs in a previously healthy individual and produces histologic findings of diffuse alveolar damage. The clinical, radiologic, and pathologic manifestations are identical to those of acute respiratory distress syndrome (ARDS); the only distinction is that no etiology is found. AIP is essentially idiopathic ARDS.
Prevalence and Epidemiology
AIP is rare, has no sex predominance, and has no association with cigarette smoking. The average age at presentation is 50 to 60 years (range, 7–83 years).
Clinical Presentation
A prodromal illness associated with symptoms suggestive of a viral upper respiratory tract infection is commonly present, with fever, chills, myalgias, and arthralgias. This is followed by dry cough and rapidly progressive and severe dyspnea. Approximately two-thirds of patients have symptoms for less than 1 week, and one-third have symptoms for 60 days before diagnosis.
Pathophysiology
Pathology
The histologic findings are those of diffuse alveolar damage ( Fig. 30.1 ). The acute, exudative phase shows edema, hyaline membranes, acute interstitial inflammation, and intraalveolar hemorrhage. The organizing (proliferative) phase shows loose organizing fibrosis and type II pneumocyte hyperplasia. Patients who survive more than 2 weeks may progress to the chronic phase with fibrosis that may be associated with extensive architectural remodeling resulting in honeycomb formation in severely fibrotic lung or, occasionally, development of cystic changes. There are no histologic features that distinguish diffuse alveolar damage in the setting of AIP from diffuse alveolar damage of known causes.
You're Reading a Preview
Become a Clinical Tree membership for Full access and enjoy Unlimited articles
If you are a member. Log in here
