Journal of April's Health: PSSM (Tying Up) Emergency, Part 1

May 2nd was a beautiful day. The sun was shining and I was ready to get my mare, April, back on track after a couple of weeks off to recover from her tumor biopsy and the injection to reduce the tumor on her back.

I had hauled over to Cowgirl Cattle Co’s location in Lynden, where I regularly ride. My good friend Lori had just moved her Morgan gelding, Marco, over to the stable so we could have more time to ride together. We enjoyed a leisurely warm-up and were just getting started on loping circles.

I was about twenty minutes into my ride when April started getting sluggish and not wanting to move forward. She just quit on me, which was unusual for her. She’s a high-energy horse and always wants to move forward, usually too fast. I got off and took a look at her. She seemed uncomfortable but I didn’t notice anything that terribly unusual. She was pretty fit so I wasn’t concerned about the ride.

Lori invited me to ride Marco around to see how he was doing. I asked Lori to just walk April to cool her down a bit while I rode Marco. April wasn’t terribly hot but I figured it was a good idea to keep her moving. After finishing up on Marco, we figured we’d call it good since neither horse had seen much work over the past couple of weeks.

Rachel, the barn manager, called me over to look at April. She was standing motionless, sweating profusely. Her head and entire body were soaking wet. We pulled the saddle off and moved her into the wash rack to try to cool her down. April couldn’t seem to get comfortable. I left her in the wash rack and went out to the trailer to put her saddle & bridle away. Upon my return, Rachel informed me that she had watched April urinate and had taken a sample. Her urine was a dark brown.

I immediately called my veterinarian. It was about 45 minutes after I stopped riding, and she had only a slight temperature but her pulse rate was a little high. Dr. Sauter recommended I get her into the clinic right away. We were just down the road, so I loaded her up and got her in.

Dr. Sauter took a look at her and realized immediately she was in distress. He gave her some Banamine to make her more comfortable. He took the urine sample we had saved, drew blood, and determined she’d had a pretty major episode of “tying up.” The danger with tying up, also known as Monday morning sickness, is possible damage to the kidneys. It’s imperative to get the horse’s system flushed out and back on track. 

April was hooked up to a catheter and give 4-15cc bags of fluids--Ringer’s Lactate Solution--through an IV. She finally urinated after the 4th bag of fluid. This time the urine was blood red. 

At this time Dr. Sauter also treated her for colic. Even though she had no symptoms of colic, he explained this is usually a side effect from the severe pain associated with the muscle cramping. He ran mineral oil into her stomach to help her pass any blockages and prevent a possible colic incident. 

Once she had urinated and seemed more comfortable (four hours later), I loaded her up and hauled her home. We left the catheter in her neck so I could again administer fluids late Saturday evening. We wanted to keep pushing fluid through her until her urine was a normal color.

We rigged up an IV at the barn. I was able to get two more bags of fluid through her system before we left her in the barn for the night. In the morning, I gave her another dose of Banamine (12 cc) and flushed the catheter. She seemed much better, had urinated several times and was having many very loose bowel movements.

Sunday morning I drove her back over to Kulshan Veterinary Hospital, where Dr. Sauter removed the catheter and gave me instructions for daily exercise and turnout. He also pulled some hair samples from her mane to send off to The University of Minnesota for a fairly new genetic test to see if she carried the mutant PSSM gene. 

Polysaccharide Storage Myopathy (PSSM) is a condition in horses where there is abnormal glycogen storage occurring in muscles, resulting in the accumulation of excessive amounts of glycogen and an unusable polysaccharide. This can result in “tying up” or rhabdomyolysis. It’s basically a metabolic muscle disorder. (Taken from article written by Karen J. Wolfsheimer, DVM, Ph.D., Dipl, ACVIM-SAIM). 

April was taken off all grain and pasture. She was only to receive local hay and stay in a dry paddock with no grazing. Dr. Sauter had me walk her twice daily for 10- to 15-minute increments to keep her muscles moving. Next week I’ll update you on the 10-day checkup and what we discovered.