Acute interstitial pneumonia

Abstract

The term "acute interstitial pneumonia" (AIP) describes an idiopathic clinicopathological condition, characterized clinically by an interstitial lung disease causing rapid onset of respiratory failure, which is distinguishable from the other more chronic forms of interstitial pneumonia. It is synonymous with Hamman-Rich syndrome, occurring in patients without pre-existing lung disease. The histopathological findings are those of diffuse alveolar damage. AIP radiologically and physiologically resembles acute respiratory distress syndrome (ARDS) and is considered to represent the small subset of patients with idiopathic ARDS. It is frequently confused with other clinical entities characterized by rapidly progressive interstitial pneumonia, especially secondary acute interstitial pneumonia, acute exacerbations and accelerated forms of cryptogenic fibrosing alveolitis . Furthermore, many authors use the above terms, both erroneously and interchangeably. It has a grave prognosis with >70% mortality in 3 months, despite mechanical ventilation. This review aims to clarify the relative clinical and pathological issues and terminology.

Hamman-Rich syndrome: a forgotten entity

“…While lung-protective strategies have shown to reduce mortality, AIP continues to be associated with a very poor prognosis. More than half of patients with AIP will die in hospital, while the majority of those who survive the initial hospitalization will die within six months [3,6,12,19]. Surprisingly, the patients who survive may have significant or nearly complete recovery of lung function [21].…”

“…The role of steroids in treatment remains unsubstantiated [4]. Prognosis is poor, with a reported mortality rate of 70% at three months [6].…”

Acute interstitial pneumonia (hamman-rich syndrome) - a life threatening respiratory disease

“…1,2 Since many clinical and pathological features of AIP are similar to those of adult respiratory distress syndrome (ARDS), it can be difficult to differentiate. AIP is frequently confused with acute multilobar infectious pneumonia, with other forms of interstitial pneumonia, such as acute exacerbation of idiopathic pulmonary fibrosis, rapidly progressive bronchiolitis obliterans-organising pneumonia or idiopathic acute eosinophilic pneumonia, with collagen-vascular diseases involving the lungs and with primary or secondary pulmonary capillaritis.…”

“…3,4,5 Acute interstitial pneumonia, which occurs over a wide range of ages, with an approximate mean age of 54. 6 AIP is radiologically and physiologically resembles acute respiratory distress syndrome (ARDS). 5 The chest radiographic and high resolution computed tomography (HRCT) scan manifestations of AIP are bilateral and sometimes patchy, and there are alveolar densities associated to areas of ground glass attenuation.…”

Rheumatoid Arthritis Interstitial Lung Disease

“…Clinically, the histological findings of AIP confer a mortality risk exceeding 50%, typically within several months of diagnosis (Katzenstein et al, 1986;Parambil et al, 2006). Patients surviving the acute syndrome are commonly left with significant morbidity and are at risk of recurrences (Bouros et al, 2000;Vourlekis et al, 2000). Finally, in addition to a vigilant search for possible infectious triggers, clinicians assessing RA patients with respiratory symptoms should also obtain detailed medication history as certain medications used for the treatment of RA, such as methotrexate, cyclophosphamide, sulfasalazine, and TNF-alpha inhibitors have potential pneumotoxic effects and can present with diffuse lung disease.…”