SESSION TITLE: Interstitial Lung Disease Case Report Posters II
SESSION TYPE: Affiliate Case Report Poster
PRESENTED ON: Tuesday, October 29, 2013 at 01:30 PM - 02:30 PM
INTRODUCTION: Hypersensitivity pneumonitis (HP) is an immunologically induced inflammation of lung parenchyma in response to inhalation of a wide variety of antigens. Antigens responsible for HP are mostly organic in nature. However, some chemicals can act as haptens for the induction of HP. Pyrethroids are common insecticides with both household and industrial uses. There has previously been only one case report of pyrethroids causing HP.
CASE PRESENTATION: A 45-year old non-smoking man with no history of lung disease was referred for evaluation of dyspnea. He worked for a freight company, which received a leaking container filled with the pyrethroid insecticide zetacypermethrin that was held in the worker’s office area for one week. It emitted strong fumes while in storage. The patient developed dyspnea a few days after this exposure and sought medical care. On exam, he was hypoxic at rest and a 6-minute walk showed that he required 5L of oxygen with activity. Pulmonary function tests showed a restrictive pattern and a significantly reduced diffusing capacity of 36% predicted. A CT scan of the thorax revealed diffuse ground glass and nodular opacities. Open lung biopsy demonstrated a chronic interstitial inflammatory process consistent with nonspecific interstitial pneumonitis (NSIP). It was concluded that he had HP. No risk factors for HP were identified other than his exposure to the pyrethroid insecticide. The patient was started on high dose prednisone, which resulted in resolution of the restriction seen on spirometry. However, his DLCO did not improve significantly and he continues to require 3 L of supplemental oxygen with exercise nine months later.
DISCUSSION: The clinical presentation, including the NSIP on open lung biopsy, is most consistent with HP. The worker’s only risk factor for this disorder was exposure to zetacypermethrin. It is more likely than not that the zetacypermethrin inhalation caused HP. Because pyrethroids are common household chemicals, he likely became sensitized from a previous exposure.
CONCLUSIONS: This case emphasizes the need to have a high suspicion for HP when evaluating a patient with restrictive lung disease who has characteristic radiographic findings. It confirms that pyrethroids belong on the growing list of antigens that can cause HP.
Reference #1: Carlson JE, Villaveces JW. Hypersensitivity pneumonitis due to pyrethrum. Report of a case. JAMA. 1977 Apr;237(16):1718-9.
Reference #2: Lacasse Y, Girard M. Recent advances in hypersensitivity pneumonitis. Chest. 2012 Jul;142(1):208-17.
DISCLOSURE: Susanna Von Essen: Consultant fee, speaker bureau, advisory committee, etc.: Speaker fees from CSL Behring The following authors have nothing to disclose: Ankit Nahata
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