PrintTwo years ago, Polly Merrill thought she was at the end of the road with Telemakhos, or "Mikey," an 8-year-old Thoroughbred she'd hoped to event.
"I was either going to turn him out or put him in the ground," said Merrill, of Sherborn, Mass. For the two years she'd had him, every day had been a struggle. He was so unruly that she wore a helmet and gloves every time she handled him. (And he still managed to break six of her ribs and give her a concussion.) He couldn't stand to be confined--he'd kick at the walls of his stall and refused to stand in the crossties.
He had to be sedated for the farrier. He'd stand still in one spot in his turnout paddock and buck. He couldn't canter. He couldn't jump a combination of crossrails without crashing through one of them. He couldn't maintain a frame while walking uphill. He spent about 20 minutes of every hour lying flat on his side in the pasture. He was skinny and hard-eyed and, in a word, miserable.
Still, Merrill adored the horse and felt sure that there was a physical cause for his issues. She and her veterinarian ran through the usual diagnostics lameness exams, bloodwork, scoping for ulcers, testing for Lyme disease. They tried massage and acupuncture. Nothing helped.
"It was going on and on and on, and I was getting more and more broke," Merrill said. Her veterinarian finally threw up her hands, told Merrill that she'd exhausted all of her theories, and suggested she get on the Internet and see what she could find.
After describing Mikey's symptoms on The Chronicle of the Horse's Internet bulletin board, Merrill was referred to a website about equine polysaccharide myopathy, a syndrome primarily characterized by increased storage of glycogen (a form of stored glucose for energy) in muscle cells. The symptoms-- vague hind end lameness/ weakness, trouble performing, abnormal gaits-- sounded similar enough to Mikey's symptoms that Merrill brought up the possibility with her veterinarian.
"She looked at me and said, 'That's only seen in draft horses,' " Merrill said.
But Merrill decided to go ahead and switch Mikey to the high-fat, low-starch diet recommended for horses with polysaccharide storage myopathy. Couldn't hurt, might help, she figured. And there was little else left to try.
Two years later, Merrill rode Mikey in his first three-day event, at the Morven Park CCI* (Va.). Although they retired on cross-country after a green mistake and a fall early in the course, Merrill was buoyant--considering the horse Mikey used to be, it was a stunning victory that they'd been able to compete at all.
"I finished phase B and asked my daughter, 'Do I have bugs in my teeth?' because I was grinning so much," she recalled with a laugh.
"My greatest reward is to have people who knew Mikey then see him now. They can't believe he's the same horse," she said.
Not A Simple Solution
Merrill is one of a growing number of sport horse owners who believe polysaccharide storage myopathy is to blame for their horses being not-quite-right, and who have found that diet changes bring about remarkable results.
But the disorder is surrounded by considerable confusion. Increased glycogen storage has been documented in a wide variety of breeds, but certain breeds seem to show different symptoms than others. It's not yet confirmed that the exact same disease is responsible for the various symptoms that seem to be shown across different breeds, although experts believe it's likely.
