Choanal Atresia

Todayโ€™s path rounds are on ๐œ๐ก๐จ๐š๐ง๐š๐ฅ ๐š๐ญ๐ซ๐ž๐ฌ๐ข๐š!

๐–๐ก๐š๐ญ ๐ข๐ฌ ๐ข๐ญ?
๐‚๐ก๐จ๐š๐ง๐š๐ฅ ๐š๐ญ๐ซ๐ž๐ฌ๐ข๐š is failure to form communication between the nasal cavity and the ๐ง๐š๐ฌ๐จ๐ฉ๐ก๐š๐ซ๐ฒ๐ง๐ฑ (large open area right before the trachea) during development. This blockage can be a single membrane, or even a bone, and may be found in both nasal passages or just one.

๐–๐ก๐จ ๐ ๐ž๐ญ๐ฌ ๐ข๐ญ?
This disease is primarily seen in alpacas and llamas, although it has been described in other species as well. It is typically diagnosed in ๐œ๐ซ๐ข๐š๐ฌ (baby alpacas or llamas) shortly after birth.

๐–๐ก๐š๐ญ ๐œ๐š๐ฎ๐ฌ๐ž๐ฌ ๐ข๐ญ?
This condition is thought to be genetic, and a few possible genes have been identified. However, the exact genetic development of the condition hasnโ€™t been determined yet!

๐–๐ก๐ฒ ๐ข๐ฌ ๐ญ๐ก๐ข๐ฌ ๐š ๐ฉ๐ซ๐จ๐›๐ฅ๐ž๐ฆ?
As you can imagine, having a blocked nasal passage is no fun for these little guys. They often have difficulty breathing, cannot exercise or run around, and often breathe through their mouths. They are very susceptible to ๐š๐ฌ๐ฉ๐ข๐ซ๐š๐ญ๐ข๐จ๐ง ๐ฉ๐ง๐ž๐ฎ๐ฆ๐จ๐ง๐ข๐š, with milk entering the lungs, because they are trying to mouth-breathe while drinking. Unfortunately, this condition has an extremely poor prognosis, and most affected crias will die from it.

๐‡๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐๐ข๐š๐ ๐ง๐จ๐ฌ๐ž๐?
Typically affected crias will be open mouth breathing, and clearly distressed. Their nostrils may be flared as they desperately try to acquire oxygen. To confirm a diagnosis, the producer can hold a mirror can be held up to each nostril to look for whether or not the mirror fogs up, indicating that the animal can breathe through that nostril.

๐‡๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ญ๐ซ๐ž๐š๐ญ๐ž๐?
Previously there have been attempts to correct the blocked nasal passage surgically, however these attempts have not been very successful. Currently the recommendation for affected crias is humane euthanasia.

๐๐ก๐จ๐ญ๐จ๐ฌ
1) A cria with flared nostrils and an open mouth due to choanal atresia.
2-4) Examples of choanal atresia on cross-section of the skull.

๐’๐จ๐ฎ๐ซ๐œ๐ž๐ฌ
Maxie, G. Jubb, Kennedy and Palmerโ€™s Pathology of Domestic Animals, Volume 2. Sixth Edition.
Johnson, L.W. Diseases of Llamas and Alpacas. Merck Veterinary Manual 2014.

Photos 1-4 courtesy of Noahโ€™s Arkive.

Leave a Reply