Gunther is a 3 year old Male Intact Weimeraner who was presented for lethargy and a decreased appetite. On physical examination he was febrile, with a temperature of 103.5, had moderate to severe peripheral lymphadenopathy, and had mild to moderate splenomegaly.
Interpretation and outcome:
Thoracic radiographs were obtained. There is a diffuse, mixed, coarse interstitial and bronchial pulmonary pattern present, with a focal alveolar pattern in the ventral aspect of the cranial segment of the left cranial lung lobe. There is an increase in soft tissue opacity dorsal to the second sternebra on the lateral radiograph. Differentials for the pulmonary disease included neoplasia, atypical infectious disease such as fungal infection or lungworm, or inflammatory disorders such as pulmonary infiltrate with eosinophils. There is evidence of sternal lymphadenopathy present, which may be secondary to neoplasia or reactive lymphadenopathy.
Tracheal wash was performed, which revealed mixed inflammation. Histoplasmosis was identified on a rectal scrape, and a diagnosis of disseminated histoplasmosis was made.
Histoplasmosis is caused by Histoplasma capsulatum, a non contagious fungus that is endemic in the Ohio, Mississippi, and Missouri river valleys. The infective mycelium enters the lung through the upper respiratory tract, converts to the yeast phase, and infects the lung. In the active stage, interstitial pneumonia with diffuse interstitial infiltrates and/ or focal areas of consolidation are typically seen. Hilar lymphadenopathy may also be present. In the chronic or healed stage, radiographic findings may include interstitial nodules, which may be mineralized, and mineralized hilar lymph nodes.