Arytenoid Chondritis - Case Study

By Dr. Joanna Bronson | http://bronsonvetservices.com/

Even veterinarians sometimes have to pay other veterinarians for treatment of their personal animals.

My daughter's quarter horse was 9 years old when she became ill after their first showing at the All-American Quarter Horse Congress this past October in Columbus, Ohio. Showing in the youth 12-14 year-old, all-around events, the duo received a 1st, 3rd, and 5th placing in their classes winning several other top 10 awards. After winning the Equitation Championship Wednesday evening, we started home, leaving our mare at the show with our trainers to follow later.

On Friday morning, we received a call. Our mare was having difficulty breathing and had spiked a fever Her situation was dire, and we were advised to have her transported to Ohio State University's College of Veterinary Medicine for emergency treatment. Upon arrival, the attending veterinarians performed a tracheostomy and began administering antibiotics and throat spray She remained at the hospital for 7 days during which surgeons partially removed the granulomas on the opposing sides of both arytenoids (“kissing lesions”).

Once the swelling went down and her breathing improved, the tracheostomy tube was pulled, and she came home for rest and continued care.

Further outpatient care was performed at Michigan State University with repeated endoscopy and laser debridement over the next 3 months.

Our mare was suffering from a disease known as Arytenoid Chondritis which is an inflammatory condition of the arytenoid cartilages in adult horses. The arytenoid cartilages are paired flaps/cartilage that lie at the opening to the trachea (windpipe).

For an asymptomatic horse, during inspiration, these flaps spread apart to let as much air as possible to pass through the trachea and into the lungs. With affected horses, the arytenoids are swollen and often have granulomas which diminish the air flow

Clinical signs don't usually appear until the later stages of the disease. Those signs include coughing, whistling, roaring, and feed and water material coming out of the horse's nostrils. Our mare didn't exhibit any warning signs until she had difficulty breathing

Cases can range from mild to severe. In mild cases, systemic antiinflammatory medication and antibiotics are combined with antiinflammatory medication delivered as a throat spray

In moderate to severe cases, a tracheostomy is performed to bypass the larynx for improved airflow. This tube allows the larynx to rest decreasing swelling.

In severe cases, an Arytenoidectomy is performed under general anesthesia with a small incision behind the horse's mandible to remove the affected cartilage so the horse can breathe without the tracheostomy tube.

This condition is most prevalent in Thoroughbreds as a progressive, inflammatory condition. Most cases are unilateral but can spread to both sides.

The precise cause of Arytenoid Chondritis is unknown but is suspected to be secondary to mucosal trauma which then leads to a viral or bacterial infection that can involve the arytenoid cartilage.

Since race horses normally race on dirt or sand, they inhale matter during their fast work triggering respiratory infections which can spread to the surrounding cartilage. The condition is very painful and can lead to laryngeal paresis or weakness.

The infection can cause excessive granulation tissue that can project into the tracheal lumen and cause partial obstruction resulting in high-pitched breathing sounds.

Diagnosis is through an upper respiratory airway endoscopy Cartilage calcification can be seen in chronic cases through x-rays, and ultrasounds.

A majority of cases are found in young (aged 2-4 years) Thoroughbreds around sale time. Most of those discovered are mild, acute, and not associated with clinical signs. These cases usually respond to broad-spectrum antibiotic treatment, followed by oral sulfonamide medication for several weeks. A daily throat spray of antibiotics and/or anti-inflammatory agents may be prescribed delivered through a nasopharyngeal catheter

Progress is monitored by serial endoscopic examinations until the lesions are healed. Horses that produce excessive granulation tissue often require surgical laser resection of the tissue. Our mare has undergone 3 rounds of laser ablation.

In severe cases exhibiting cartilage deformation, or that are nonresponsive to treatments, a partial arytenoidectomy may be required. In race horses, this procedure may limit or end their racing careers. Most horses will still be useful in less strenuous careers.

Our mare continues to slowly improve. We are hopeful that she will be able to resume her previous level of competition, and the prognosis seems favorable at this time.

We remain unclear about the cause and no horse is exempt from this disease. Despite our best efforts, illness can happen.

Dr. Joanna Bronson graduated from MSU College of Veterinary Medicine in 2000 at the top of her class. Following graduation, she worked as an intern at a large equine referral practice in Cleveland, OH, specializing in lameness, surgery, and racetrack medicine. In 2005, she opened Bronson Veterinary Services in Coldwater, MI. What started as an ambulatory only practice, quickly grew to a fullservice equine and small animal hospital and surgical center The now three doctor practice provides medical, surgical, reproductive, and preventative care services for Branch County and the surrounding area.

For more information please visit: http://bronsonvetservices.com/