Todayโs path rounds are on ๐๐ฅ๐๐ฌ๐ญ๐จ๐ฆ๐ฒ๐๐จ๐ฌ๐ข๐ฌ!
๐๐ก๐๐ญ ๐ข๐ฌ ๐ข๐ญ?
๐๐ฅ๐๐ฌ๐ญ๐จ๐ฆ๐ฒ๐๐จ๐ฌ๐ข๐ฌ is a fungal infection found throughout the world, however we most commonly see cases in North America.
๐๐ก๐จ ๐ ๐๐ญ๐ฌ ๐ข๐ญ?
We most commonly see this disease in dogs and cats, however it can infect other species as well. It can also infect humans!
๐๐ก๐๐ญ ๐๐๐ฎ๐ฌ๐๐ฌ ๐ข๐ญ?
Blastomycosis is usually caused by ๐๐ฅ๐๐ฌ๐ญ๐จ๐ฆ๐ฒ๐๐๐ฌ ๐๐๐ซ๐ฆ๐๐ญ๐ข๐ญ๐ข๐๐ข๐ฌ. This fungus has two forms, the ๐ฆ๐ฒ๐๐๐ฅ๐ข๐๐ฅ ๐๐จ๐ซ๐ฆ that produces spores, and a ๐ฒ๐๐๐ฌ๐ญ ๐๐จ๐ซ๐ฆ. The mycelial form grows in the soil, contaminating the environment. When the spores are inhaled by an animal, the fungus transforms into the yeast form in the lungs. Once the fungus sets up shop in the lungs, it is able to gain access to the bloodstream and lymphatics and spread to other organs. The fungus likes to spread to bones, eyes, skin and joints in particular.
๐๐ก๐ฒ ๐ข๐ฌ ๐ญ๐ก๐ข๐ฌ ๐ ๐ฉ๐ซ๐จ๐๐ฅ๐๐ฆ?
Wherever Blastomyces spreads in the body, it produces a ๐ ๐ซ๐๐ง๐ฎ๐ฅ๐จ๐ฆ๐๐ญ๐จ๐ฎ๐ฌ ๐ซ๐๐ฌ๐ฉ๐จ๐ง๐ฌ๐, or inflammation with large numbers of ๐ฆ๐๐๐ซ๐จ๐ฉ๐ก๐๐ ๐๐ฌ, one of the bodyโs major clean-up cells. This inflammation characteristically forms large, grey to white nodules around the yeast. These ๐ ๐ซ๐๐ง๐ฎ๐ฅ๐จ๐ฆ๐๐ฌ can cause compression of surrounding tissue and interfere with the organโs normal function. This typically presents as cough, difficulty breathing, swollen lymph nodes, blindness, or lameness, depending on what organs or tissues are affected.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐๐ข๐๐ ๐ง๐จ๐ฌ๐๐?
Blastomycosis can be diagnosed on ๐๐ฌ๐ฉ๐ข๐ซ๐๐ญ๐๐ฌ, where a sample of cells is taken, or on ๐๐ข๐จ๐ฉ๐ฌ๐ฒ, where a section of tissue is removed. The fungus has a characteristic ๐๐ซ๐จ๐๐-๐๐๐ฌ๐๐ ๐๐ฎ๐๐๐ข๐ง๐ , which basically means it looks like a snowman when the yeast divides to make more fungus. This finding can easily be seen under the microscope!
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ญ๐ซ๐๐๐ญ๐๐?
Blastomycosis can be treated by our typical anti-fungal medications, however the prognosis is quite poor for more severe cases of lung disease.
๐๐ก๐จ๐ญ๐จ๐ฌ
1) An X-ray showing blastomycosis in the lungs. Normally the lungs are ๐ซ๐๐๐ข๐จ๐ฅ๐ฎ๐๐๐ง๐ญ (black), whereas these lungs look pretty cloudy!
2) An aspirate showing snowmen blasto!
3-5) Lungs with multiple white granulomas of blasto.
6) An eye containing a bunch of extra tissue, thanks to a granuloma forming within the eye!
๐๐จ๐ฎ๐ซ๐๐๐ฌ
Maxie, G. Jubb, Kennedy and Palmerโs Pathology of Domestic Animals, Volume 2. Sixth Edition.
Taboada J. Blastomycosis. Merck Veterinary Manual 2020.
Photos 1-6 ยฉ Noahโs Arkive contributors Niyo, French, Harrington, Selcer, Howard licensed under CC BY-SA 4.0.
