Fatal Hypersensitivity Pneumonitis from Exposure to Fusarium vasinfectum in a Home Environment: A Case Report

Hypersensitivity pneumonitis (HP) is a rare, non-IgE-mediated inflammatory lung disease caused by inhalational exposure to various antigens found in occupational, avocational and home environments. The prognosis is favorable with early detection and prompt removal of the causative agent, and fatalities are unusual. We present a fatal case of HP caused by chronic exposure to Fusarium vasinfectum mold in the home.

A 37-year-old white male presented with a 6-month history of progressively worsening dyspnea, cough, weight loss and fatigue associated with the self-renovation of his water-damaged, mold-infested mobile home. Evaluation included a physical examination (hypoxia, inspiratory crackles and expiratory rhonchi), baseline pulmonary function testing (mixed obstructive/restrictive pattern), chest computed tomography (bronchiectasis, fibrosis and diffuse interstitial involvement), bronchoalveolar lavage (macrophages 20%, lymphocytes 28% and neutrophils 52%) and transbronchial biopsy (interstitial fibrosis and chronic inflammatory infiltrate). Mold culture from the home grew out F. vasinfectum. An Ouchterlony double diffusion technique documented high antibody titer to F. vasinfectum. Despite aggressive intravenous corticosteroid treatment, the patient's lung function declined to the extent that he could not be removed from ventilator support following an open lung biopsy, eventually resulting in death.

This is the first reported case of fatal HP related to an acute exacerbation of a chronic form of HP following continuous and intense exposure to F. vasinfectum. Although uncommon, a high index of suspicion for HP is necessary in patients with progressive respiratory symptoms and known environmental antigen exposure. With early detection and prompt removal of the causative antigen, HP prognosis is generally favorable, but can progress to fatal disease with continued exposure.