Hypersensitivity pneumonitis diagnosis

If a diagnosis of amiodarone-induced hypersensitivity pneumonitis is made, discontinue amiodarone and institute steroid treatment. If a diagnosis of amiodarone-induced interstitial/alveolar pneumonitis is made, institute steroid therapy and discontinue amiodarone or, at a minimum, reduce dosage. 

Hypersensitivity pneumonitis has been attributed to occupational exposure to tetrachloroethylene in a 42-year-old dry cleaner the diagnosis was confirmed by lung biopsy (1). 

Table 2 (2,13,14) (Hgs. 2 and 3). Ground glass opacities (GGO) may be present in UIP, but are nevCT the dominant feature (2,13). Extensive GGO suggest an alternative diagnosis [e.g., DIP, NSIP, or hypersensitivity pneumonitis (HP)] (13). Honeycomb change (HC) is often a prominent feature in UIP, but is uncommon in other HPs (2,9,14). Zones of emphysema (typically in the upper lobes) may be present in smokers (15,16). Mediastinal lymphadenopathy occurs in 55% to 71% of patients with UIP, but is nonspecific (17-19).

Lacasse Y, Selman M, Costabel U, et al. Clinical diagnosis of hypersensitivity pneumonitis. Am J Respir Crit Care Med 2003 168(8) 952-958. 

The differential diagnosis of LIP is low-grade marginal zone B-cell lymphoma of MALT (MALToma) and interstitial pneumonitides in the lung, including nonspecific interstitial pneumonitis and hypersensitivity pneumonitis (Table 2). 

Corticosteroids are the current standard treatment of OP (2,6,9,11,16-19), although spontaneous improvement has occasionally been reported (2). Clinical improvement is usually observed within two days after treatment onset. At imaging, pulmonary infiltrates usually markedly improve within a few days and disappear completely within a few weeks. The speed of response to corticosteroids in OP is slower than in chronic idiopathic eosinophilic pneumonia, but faster than in NSIP and roughly comparable to hypersensitivity pneumonitis. The spectacular and reproducible response to corticosteroids can further be considered as an additional diagnostic feature of the clinical syndrome of OP, and if this response is poor, the initial diagnosis should be reconsidered. Removal of the causing agent should be done in secondary OP, whenever possible. 

Emanuel DA, Marx JJ, Ault BJ (1989) Organic dust toxic syndrome (pulmonary mycotoxicosis) - a review of the experience in central Wisconsin. In Dosman JA and Cockcroft DW (eds) Principles of health and safety in agriculture. CRC Press, Boca Raton, pp 72-75 Fink JN et al. (1971) Precipitins and the diagnosis of a hypersensitivity pneumonitis. J Allergy Clin Immunol 48(3) 179-181... 

Diagnosis of hypersensitivity pneumonitis (HP), or extrinsic allergic alveolitis, has most often relied... 

Schuyler M, Cormier Y (1997) The diagnosis of hypersensitivity pneumonitis. Chest 111 534-536... 

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