Alveolated airways

PULM pulmonary region (alveolated airways and alveoli). 

Continued lung injury from inhalation of particulates, whatever their source, size, or composition, produces inflammation (alveolitis, bronchitis), and perhaps eventually fibrosis, a pathological reaction that distorts the architecture of the airways (Lippman et al., 1971). Lung function is compro-... 

Hypersensitivity pneumonitis (HP), or extrinsic allergic alveolitis, represents a heterogeneous group of disorders resulting from repeated exposure to a variety of organic particles, which provokes, in a susceptible host, an immunologically mediated inflammation of the small airways and lung parenchyma (1). 

LIP and hypersensitivity pneumonitis (extrinsic allergic alveolitis) may be difficult to distinguish. Radiographically, both show bilateral infiltrates. Microscopically, hypersensitivity pnemnonitis may resemble LIP in showing interstitial lymphocytic infiltrates containing ill-formed granulomas. Hypersensitivity pneumonitis has a patchier (airway-centered) and milder interstitial pneumonitis, and it can show bronchiolitis obliterans, a feature not seen in LIP. 

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