JOURNAL OF THE LOUISIANA STATE MEDICAL SOCIETY
Figures 3-5. Axial lung algorithm CT images demonstrate diffuse distribution of milliary predominant interstitial pattern in both lungs. 3 4 5
is rare in an immunocompromised patient when compared to infections caused by Histoplasmosis and coccidoidomycosis. 3
CT imaging, though providing more vivid details of the anatomy and pathology, does little to provide specific characteristics to aid in making a definitive diagnosis. 5 CT findings commonly, in line with findings found on plain films, exhibit nonspecific air bronchograms, consolidations, and nodules. 5 The retrospective study, which examined 34 CT images of known blastomyces infections, was inconclusive in determining characteristics commonly associated with blastomycotic disease. 5 The study by Winer-Muram et al. did, however, mention that a combination of central mass lesions, consolidation, air bronchograms, intermediate-sized nodules, satellite lesions, and no lymphadenopathy and pleural disease should raise suspicion of blastomycosis. 6 Even with such high quality imaging, the differential for blastomycosis remains large. On the differential, a clinician should consider other infectious processes, pseudolymphoma, and malignant neoplasms. 5,6 Therefore, a clinician should always remain mindful that while Blastomycosis often will have findings on imaging, it will by no means provide a way to create a specific diagnosis. Blastomycosis is an infection that is often overlooked due to its variety of presentations and nonspecific symptoms. Furthermore, the ambiguity often seen with imaging makes having a definitive diagnosis early nearly impossible. Instead, clinicians often have to wait until culture results are returned from offsite facilities. This creates the potential for rapid progression of the disease, and ultimately, putting the patient at risk. Thus, if there is strong sense of suspicion, it is important that Blastomycosis always remain on a differential.
Clinically, Blastomycosis can present from a benign dry cough all the way to a life-threatening acute respiratory distress syndrome (ARDS). 3 Though most people exposed to the fungus are infected, less than half exhibit any clinical symptoms. 5 Patients often acutely present with nonspecific symptoms of cough, fever, and chills, which prompts the clinician to order imaging. 3 More commonly, patients exhibit chronic pulmonary symptoms. These often include intermittent low grade fevers, chest pain, and persistent cough. 3 Due to such nonspecific symptoms, Blastomycosis is often late to be diagnosed and can often progress to more severe infections. In its more fulminant presentation, Blastomycosis shows rapidly progressing pulmonary deterioration, often culminating with the patient in ARDS.3 Additionally, the fungi oftenmanifestswithextrathoracic symptoms. 3 These can present as warty lesions on the skin, lesions in the bone, infections in the male GU organ system, or CNS manifestations. 3 With a wide variety of presentations, blastomycosis is often difficult to diagnose until more definitive measures, such as imaging and cultures, are implemented. Blastomycosis, similar to its clinical presentation, varies widely in how it is seen on imaging. This further complicates the diagnostician’s ability to make a definitive diagnosis. Most commonly, roentgenographically the disease is seen as airspace consolidation, estimated to be in about 26-76% of the cases. 3 However, other manifestations include appearing as masses in up to 31%, intermediate sized nodes seen in around 6%, interstitial disease often showing the classical “tree in bud” appearance, miliary disease seen in around 11-28%, or as a cavitary lesion. 3 Winer-Muram et al., in their review of clinical and radiographic features of blastomycosis, commented on the lack of lymphadenopathy and pleural effusions, which can often be used to help distinguish between other pulmonary infectious processes. 6 With such wide variety of presentation seen on plain film, it is no surprise many clinicians feel the need for using CT imaging.
112 J La State Med Soc VOL 169 JULY/AUGUST 2017
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