INTRODUCTION: We report a case of chronic hypersensitivity pneumonitis caused by a fungal organism found in rotting wood bark.
CASE PRESENTATION: A 50 year old woman with a past medical history significant for ulcerative colitis presented to the emergency room with abdominal complaints. A CT of the abdomen revealed incidental finding of nodular and tree-in-bud opacities of the lower lungs. A dedicated CT of the lungs demonstrated bilateral ill-defined numerous small pulmonary nodules with basilar predominance, along with patchy ground glass opacities. Also noted were multiple calcified mediastinal and hilar lymph nodes bilaterally. She was referred to a pulmonology clinic for evaluation. Her respiratory complaints were minimal. She had mild dyspnea when ascending a flight of stairs, but no dyspnea exercising on level ground, and no other respiratory complaints, such as cough or wheeze. She complained on night sweats, which she attributed to perimenopausal symptoms. Her only medications were antidepressants. Since having a proctocolectomy 15 years ago, her inflammatory bowel disease has been quiescent. She has never smoked, drank alcohol, or used recreational drugs. Her travel history includes South America and extensive travel in the United States. She has no pets. She gardens daily. Over the past two years, she has been digging in rotting bark mulch. Initial examination was unremarkable, except for a room air SaO2 of 88%. Spirometry was normal (FEV1 2.91L, FVC 3.64L), and DLCO was mildly reduced (22.27 mL/mmHg/min). Serologic testing was performed to evaluate for occult collagen vascular disease, and was negative. A bronchoscopy was performed with lavage. The airways appeared normal. The lavage was unremarkable (68% macrophages, 24% lymphocytes, 8% bronchial lining cells), with no evidence for malignancy, Pneumocystis, fungal or viral infection. The lavage culture grew Penicillium species. The patient underwent video-assisted thorascopic surgery of the right lung, with biopsies of the upper, middle, and lower lobes. The pathologic examination revealed numerous noncaseating granulomata and mild to moderate emphysematous changes. While no fungal elements were seen on pathologic examination, the tissue cultures grew Phanerochyte chrysosporium from the upper and lower lobes. The patient was referred to an infectious disease specialist, and was empirically treated with oral voriconazole, 200mg bid. She stopped gardening. She underwent 6 months of antifungal therapy, with no significant change in her spirometry, or DLCO. She reported some mild improvement in symptoms during the first 2 months of antifungal therapy. A repeat CT of the chest at that time demonstrated significant improvement in ground glass opacities, with persistent nodules and calcified lymph nodes. The voriconazole was discontinued and prednisone was initiated (20mg daily). After 2 months of therapy, the patient reported mild subjective improvement in dyspnea. Spirometry demonstrated non-significantly increased DLCO (24.43 mL/mmHg/min). The prednisone was tapered off over a period of 2 months, with no significant change in spirometry, DLCO, or subjective dyspnea.
DISCUSSION: Phaenerochyte chrysosporium, a fungus found in decaying wood, has not been reported as a pathogen in humans before, although it has been reported to cause hypersensitivity pneumonitis in animal models. We believe this patient’s lung disease is a hypersensitivity pneumonitis as a result of chronic exposure to this fungus while gardening with rotting wood mulch. While the patient’s histologic and radiographic findings can be seen in sarcoidosis, the patient’s radiographic improvement occurred with administration of an antifungal medication and avoidance of the offending agent.
CONCLUSIONS: Phaenerochyte chrysosporium is found in decaying wood mulch, and caused chronic hypersensitivity pneumonitis in a gardener. Its clinical presentation appeared similar to sarcoidosis, but had radiographic improvement with antifungal therapy and avoidance of gardening.
Reference #1 Fogelmark, B.; Rylander, R. Hypersensitivity pneumonitis after inhalation of single microorganisms. American Review of Respiratory Disease 1990 Vol. 141 No. 4 part 2 pp. A313
Reference #2 Tien, M.; Kirk, T.K. Lignin-Degrading Enzyme from the Hymenomycete Phanerochaete chrysosporium Burds. Science 12 August 1983: 661-663.
DISCLOSURE: The following authors have nothing to disclose: Lanspa Michael, Nathan Hatton
No Product/Research Disclosure Information