What We Know About Immune-Mediated Myositis in Horses

Horses with myositis experience rapid, widespread gluteal and epaxial muscle atrophy. Here’s what veterinarians know about about this immune-mediated condition.
Share
Favorite
Close

No account yet? Register

ADVERTISEMENT

Myositis
Horses with IMM experience rapid, widespread muscle atrophy of the gluteal muscles, along with the epaxial muscles that run along either side of the spine. | Photo: iStock

Immune-mediated myositis (IMM) is a sometimes-fatal muscle disease that occurs predominantly in Quarter Horses and related breeds. Veterinarians know very little about the condition and affected horses’ likelihood of survival, so Lazslo Hunyadi, DVM, MS, PhD, Dipl. ACVIM, a practitioner with Equine Sports Medicine and Surgery, in Weatherford, Texas, conducted a retrospective study to find out. He presented his findings at the 2017 American Association of Equine Practitioners convention, held Nov. 17-21 in San Antonio, Texas.

Horses with IMM experience rapid, widespread muscle atrophy (wasting) of the gluteal muscles, along with the epaxial muscles that run along either side of the spine. They also demonstrate generalized muscle stiffness and lethargy.

Hunyadi partnered with veterinarians from the University of California, Davis (UC Davis), and looked at medical records from that hospital of horses diagnosed with IMM from 1991 to 2014. They found 68 horses with a definitive diagnosis of IMM via muscle biopsy. Of these, 76% were Quarter Horses, 14% were Thoroughbreds, and 8% were other breeds such as warmbloods and Arabians. The Quarter Horses tended to be younger, with the average age less than 4 years old, while the average among other breeds was more than 10. The average hospital stay was 10 days

Create a free account with TheHorse.com to view this content.

TheHorse.com is home to thousands of free articles about horse health care. In order to access some of our exclusive free content, you must be signed into TheHorse.com.

Start your free account today!

Already have an account?
and continue reading.

Share

Written by:

Alexandra Beckstett, a native of Houston, Texas, is a lifelong horse owner who has shown successfully on the national hunter/jumper circuit and dabbled in hunter breeding. After graduating from Duke University, she joined Blood-Horse Publications as assistant editor of its book division, Eclipse Press, before joining The Horse. She was the managing editor of The Horse for nearly 14 years and is now editorial director of EquiManagement and My New Horse, sister publications of The Horse.

Related Articles

Stay on top of the most recent Horse Health news with

FREE weekly newsletters from TheHorse.com

Sponsored Content

Weekly Poll

sponsored by:

When do you begin to prepare/stock up on products/purchase products for these skin issues?
36 votes · 36 answers

Readers’ Most Popular

Sign In

Don’t have an account? Register for a FREE account here.

Need to update your account?

You need to be logged in to fill out this form

Create a free account with TheHorse.com!