JOURNAL OF THE LOUISIANA STATE MEDICAL SOCIETY
RADIOLOGY CASE OF THE MONTH TB or Not TB... That is the Question
Kartik Kansagra, BS, Stefan Ploch, MD, Harold R. Neitzschman MD
45-year-old female presenting initially with fever, nonproductive cough, night sweats, pleuritic chest pain, fatigue and weight loss over the past month.
RADIOLOGIC DIAGNOSIS
Diffuse Miliary Interstitial Pattern of Blastomycosis
CASE REPORT
This is a case report of a 45-year-old woman who presented initially with fever, nonproductive cough, night sweats, pleuritic chest pain, fatigue, and weight loss over the past one month. Additionally, her past medical history was significant for a kidney transplant. Her medications included numerous immunosuppressant and antiviral medications. Initial imaging with a chest radiograph (figure 1) showed diffuse small nodular opacities, which was confirmed with subsequent computerized tomography (CT) imaging. CT images (figures 2-5) demonstrated diffuse distribution of miliary predominant interstitial pattern in both lungs. The interstitial miliary pattern differential diagnosis is extensive and indicates a hemotogenously distributed process which includes infectious (classically TB), neoplastic and inflammatory processes. Initial treatment centered on a diagnosis of TB. However, after three negative sputum AFB cultures, a bronchoalveolar lavage sample confirmed the diagnosis of Blastomycosis.
Figure 1. PA chest radiograph shows diffuse small nodular opacities distributed throughout both lungs.
DISCUSSION
Blastomyces Dermatitidis is a dimorphic fungi known to cause a wide spectrum of presentations. Blastomyces is endemic to the Ohio and Mississippi River basins, Great Lakes regions, and the southeastern U.S. 1,2,4 The prevalence is estimated to be around 1 in 100,000 but can be as high as 40 in 100,000 in hyperendemic regions. 3 The organism, due to its dimorphic characteristics, can be observed in either the mycelial phase or the yeast phase.4 The mycelial phase, seen in the environment, is the form that is commonly inhaled, and the yeast phase is the form seen in the body of an infected individual. 4 Microscopically, the fungus is known for its broad based buds ranging in size from 8-15um. 3,4 Blastomycosis is most commonly known for its pulmonary infectious manifestations. While these may range in severity and presentation, the most common form is self-limiting in an immunocompotent patient. 5 Interestingly, Blastomycosis
Figure 2. Coronal CT image without contrast demonstrates a miliary predominant interstitial pattern with distribution throughout the upper and lower lung zones.
J La State Med Soc VOL 169 JULY/AUGUST 2017 111
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