A 47-year-old female, a resident of Mexico City, presented with fever, cough, and dyspnea. Her illness had started with a productive cough approximately 10 days prior during a family trip to the state of Chiapas, Mexico. At that time she was prescribed levofloxacin with no relief, followed by azithromycin and prednisone with temporary improvement of symptoms. Upon arrival to the USA, she became febrile and more dyspneic, which prompted her visit to the emergency department (ED). There was no personal history of TB.
Vital signs on admission were notable for a pulse of 108 beats/min, a temperature of 102  F, and an oxygen saturation of 88% on room air that improved to 95% with 4 L/minute of oxygen via nasal cannula. Laboratory evaluation was significant for a mild leukocytosis (12 K/muL) and normal serum electrolytes. Liver function tests were unremarkable. Rapid testing for HIV was negative. Serial chest radiography revealed a rapidly progressive diffusely nodular infiltrate (Fig. 1A and B). Computed tomography (CT) of the chest confirmed the presence of innumerable nodules (Fig. 1C).
She was started on ceftriaxone for community-acquired pneumonia and on an empiric anti-tuberculous regimen. Blood cultures and sputum mycobacterial smears returned negative. Despite the aforementioned antimicrobial regimen, the patient remained febrile with a requirement for oxygen via 50% face mask. Bronchoscopic biopsies were performed but were non-diagnostic, described as interstitial lymphocytic infiltration without granulomas.
Upon further questioning, she mentioned entering Mayan ruins in Palenque during her visit to Chiapas. She likewise informed her clinicians that her children, who had accompanied her on that trip, were now ill in Mexico with "nodules in their lungs." Liposomal amphotericin B (L-AmB) was started empirically for histoplasmosis, and the patient was referred for surgical lung biopsy, which revealed necrotizing granulomatous inflammation with fungal forms consistent with H. capsulatum (Fig. 2A and B). Subsequently her urine Histoplasma antigen assay returned positive (1.31 ng/ml, Quest Diagnostics, Inc., Teterboro, NJ, USA). She clinically improved after 8 days of L-AmB therapy and was discharged home to Mexico with instructions to complete a 12-week course of oral itraconazole 200 mg twice daily.
C, CT scan of the chest showing numerous ill-defined nodules in a centrilobular distribution (arrows).