A 40-year-old man with inconsistently treated HIV infection presented with a progressive cough, dyspnea, and pleuritic chest pain over a two-week period which were associated with fevers, chills, night sweats, and a 40-pound weight loss. He emigrated from Mexico 10 years prior and had traveled to the central valley of California. On physical exam, he was afebrile, but hypoxic and tachypnic with bilateral lower lobe crackles, and decreased breath sounds. He had evidence of oral thrush. The rest of his exam, including the neurological and skin exam, was normal. Chest X-ray and CT scan showed diffuse micronodularities with cavitary lesions in both lungs. Lab results revealed a CD4 count and viral load of 5 cells/mcL and 15,000 copies/mL, respectively. Tests for coccidiomycosis, cryptococcosis, and tuberculosis were negative but Histoplasma urine antigen was positive. Bronchoalveolar lavage (BAL) and lung biopsy showed fungal organisms with hyphae and yeast forms, as well as non-necrotizing granulomas. Culture results with genetic probe were negative for Histoplasma. Fungal cultures obtained from BAL grew the species of Emmonsia helica. Treatment was initiated on admission with IV fluconazole and was then broadened to micafungin followed by amphotericin-B based on culture results. Hospital course was complicated by spontaneous pneumothorax and two episodes of respiratory failure requiring endotracheal intubation, after which the patient was transitioned to comfort care.
Discussion:
Emmonsia species rarely infects humans, and those who do become ill are typically immunocompromised. Three species have been implicated in previously described Emmonsia infections: E. crescens, E. parva, and E. pasteuriana. Conidia occurring in soil are inhaled and convert to yeast-like cells, which are able to disseminate. Documented infections reported constitutional symptoms, anemia, and skin lesions in >95% of patients infected with E. pasteuriana. Radiographic abnormalities exhibit a nodular pattern and often resemble miliary tuberculosis, while histopathology shows non-necrotizing granulomas and may mimic Blastomyces and Histoplasma. Diagnosis is made by DNA sequencing. Histoplasma urine antigen may be falsely positive in patients with other fungal infections, including aspergillosis, coccidioidomycosis, blastomycosis, and, evidently, Emmonsia infection. Success has been noted previously with amphotericin-B and itraconazole, although mortality with disseminated infection in immunocompromised individuals is close to 50%. To our knowledge, this is the first case of infection with Emmonsia helicaspecies in a human described in the United States.
Conclusions:
Novel species of fungi such as Emmonsia helica may infect immunocompromised individuals and mimic other more common fungi; more research and observations are needed to better characterize the pathogen, understand its clinical presentations, and identify appropriate anti-fungal treatment.