Acute interstitial pneumonia
 Discussion of Acute interstitial pneumonia
- Acute interstitial pneumonia (AIP) is the only entity among the idiopathic intersitial pneumonias with acute onset of symptoms.
- In most cases of AIP, the clinical and imaging criteria for acute respiratory distress syndrome are fulfilled.
- Patients who present with AIP have a mean age of 50 years.
- Most patients develop severe dyspnea with a need for mechanical ventilation within less than 3 weeks.
- Men and women are equally affected
- Treatment is largely supportive and consists of oxygen supplementation.
- Corticosteroids seem to be effective in the early phase of disease.
- Prognosis remains poor, with a mortality rate of 50% or more.
- Histologic pattern of AIP includes diffuse alveolar damage.
- Histopathologic investigation is necessary for a definitive diagnosis of AIP.
 Imaging Findings for Acute interstitial pneumonia
- The radiographic and high-resolution CT features of AIP are similar to those of acute respiratory distress syndrome; however, patients with AIP are more likely to have a symmetric, bilateral distribution with a lower lobe predominance.
- The costophrenic angles are often spared.
- In the early phase of AIP, ground-glass opacities are the dominant CT pattern and reflect the presence of alveolar septal edema and hyaline membranes. Areas of consolidation are also present but are usually less extensive and limited to the dependent area of the lung.
- In the late phase of AIP, architectural distortion, traction bronchiectasis, and honeycombing are the most striking CT features and are more severe in the nondependent areas of the lung. This can be explained by the "protective" effect of atelectasis and consolidation on the dependent areas of the lung during the acute phase of disease.
 See Also
 External Links
- Christina Mueller-Mang, Claudia Grosse, Katharina Schmid, Leopold Stiebellehner, and Alexander A. Bankier. What Every Radiologist Should Know about Idiopathic Interstitial Pneumonias. RadioGraphics 2007 27: 595-615.