Abstract | April 6, 2022

BLASTOMYCOSIS: A GREAT MIMICKER

Presenting Author: Abhinav Vyas, MD, Internal Medicine Resident PGY1, Department of Medicine, North Alabama Medical Center, Florence, Alabama

Coauthors: Abhinav Vyas, MD, Internal Medicine, PGY1 , North Alabama Medical Center, Florence, AL; Sucheta Kundu, MD, Internal Medicine, PGY2, Internal Medicine, North Alabama Medical Center, Florence, AL; Suman Sapkota, MD, Internal Medicine, PGY1, North Alabama Medical Center, Florence, AL; Utibe Ndebbio, MD, Internal Medicine, PGY3, North Alabama Medical Center, Florence, AL; Anjum Saaquib , MD, Associate Program Director, North Alabama Medical Center, Florence, AL.

Learning Objectives

  1. To discuss about blastomycosis and how it can mimic bacterial pneumonia and tuberculosis.
  2. To discuss diagnosis and management of pulmonary blastomycosis.

Introduction: Blastomyces dermatitidis is a dimorphic fungus endemic to Ohio and Mississippi valleys in North America. Acute pulmonary infection caused by inhalation of their spores can often mimic tuberculosis and bacterial pneumonia. Pulmonary blastomycosis presents as chronic cough, weight loss, and hemoptysis. Hence most cases of blastomycosis are usually diagnosed once they have become chronic. Here we present an interesting case of blastomycosis in a young immunocompetent adult from non- endemic area.

Case Discussion: Our patient is a 19-year-old gentleman with prior COVID-19 pneumonia who came to ER with complaints of fever (105 °F) and chills, associated with productive cough, hemoptysis, dyspnea, night-sweats and joint pains. He also complained of decreased appetite and weight loss of around 30 pounds in past 3 weeks. The patient was incarcerated recently and had been in contact with his Guatemalan colleagues for the past 3 months.

On presentation, he was in mild distress and chest examination demonstrated bilateral rhonchi. Laboratory findings showed WBC 6500, D-dimer 5.83 and VBG lactate 3.0. Chest x-ray revealed diffuse interstitial markings with nodular pattern throughout lungs consistent with interstitial disease. CTA showed micronodules scattered throughout lungs with enlarged perihilar, pre-tracheal, and subcarinal lymph nodes suggesting disseminated tuberculosis or acute silicosis. How-ever his QuantiFERON TB Gold came back negative but fungal serology was positive for Blastomyces dermatitidis antigen.

He was kept in negative pressure room and initially started on vancomycin and meropenem. After Blastomyces antigen came positive, his antibiotics were discontinued and he was started on fluconazole 800 mg p.o. for the first day and then 400 mg daily for 6-12 months.

Conclusion: Pulmonary blastomycosis is often misdiagnosed as tuberculosis. Negative mycobacterial cultures and absence of response to anti-tubercular treatment should raise the suspicion of blastomycosis. Hence low thresh-hold should be kept in diagnosing blastomycosis even in suspected TB cases.

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