The Impact of Impaction

In this excerpt from his memoir of a traveling veterinarian Never Trust a Sneaky Pony, Dr. Madison Seamans shares the story of an Arabian with a mystery bellyache.

“I hope you’re close by, Doc.” The panic-stricken voice crackled through the poor reception of my cellular phone. “I think Jade is colicking again.”

The recent stormy weather made the electronic marvel that was my phone a little moody, but I got enough of the message to turn my truck around and head south.

Susan was the manager of an Arabian horse farm near Carmel Valley, at the southern end of my practice area. An excellent horseman, she had the ability to spot problems early, and her careful observations had saved the day on many occasions. She knew that when a horse refused to eat, it usually meant trouble, and there was no time to waste. Although she was always professional, I knew her normally calm demeanor was shaken because the subject of her concern, a fine mare named Jade…who was her horse.

I examined Jade and her condition was “ADR.” That’s a fancy medical term that stands for “Ain’t Doin’ Right.” Although she was off her feed, she was not demonstrating other signs that are usually associated with colic: rolling, sweating, looking at her belly, or having a rapid pulse and respiration rate. I listened to her abdomen with my stethoscope on both her left and right sides and noticed that her gut sounds were depressed.

Jade had experienced some minor colic episodes in the recent few days, and it appeared that while my treatment was helping control the pain, the condition had not yet been resolved. I rolled up my sleeve and performed a rectal exam on the gentle mare. Jade probably thought the procedure did more harm than good, as she already had more pressure in her abdomen than she wanted. She had a good attitude about it, though, and stood well while I explored as much of her abdominal cavity as my limited arm would allow.

Most folks don’t realize that the “abdominal cavity” (the belly) of a horse is as big as it is. A standard, half-ton horse has about one hundred feet of bowel that contains up to fifty gallons of ingesta at any given time. The abdominal cavity, containing both large and small bowels, extends from the pelvis to about the level of the sixth rib. In other words, much of what we consider the “chest” of a horse is actually the abdomen. The thoracic cavity contains the heart at the level of about the second through fifth ribs, and the lungs, which are above a line from the elbow to the pelvis. The “thoracic cavity,” or chest, is fairly narrow when compared with the rest of the “barrel” of the horse. Therefore, the lungs occupy a thin slice of the outsides of the barrel surrounding the guts on both sides. With this in mind, it would be impossible to feel the entire contents of the abdominal cavity with one skinny, un-tall Texan’s arm.

The only abnormality detected on my examination of Jade was a displacement of the spleen and left kidney. This indicated that there was probably an impaction in the large bowel somewhere in the front half of the abdominal cavity. Because of the blockage caused by the impaction, there was a buildup of gas in the bowel, which, in turn, caused the spleen and kidney to be pushed backward. Although I couldn’t exactly feel the impaction, the change in the location of the spleen and kidney was good circumstantial evidence, the same way that traffic backs up on the freeway for a couple of miles behind a wreck. Even though you didn’t see the accident, it’s a safe bet that there was one.

Next, I passed a stomach tube through Jade’s right nostril into her esophagus and down into her stomach. I injected some water in the tube once I was certain that it was in the stomach and looked for gastric reflux. This is done by attempting to siphon off water from the stomach and is something I look for but hope not to find. The presence of gastric reflux is indicated by siphoning out more water than was put in. This suggests the presence of either a severe blockage in the front part of the bowel, or a condition called “anterior enteritis”—either one of which is bad.

Since there was no gastric reflux, I pumped a gallon of mineral oil into the mare’s stomach. This helps to lubricate the contents of the bowel and break up an impaction, which, at the time, was what I thought to be the problem. In addition, I gave her an injection of Banamine® with some smooth-muscle-relaxing capabilities to ease the cramps.

Illustration courtesy of Madison Seamans, MS DVM

“I think she has a stubborn impaction in her dorsal colon,” I said, “but it should break up soon. There is still nothing that I can feel that would indicate a twisted gut, and that’s a relief. Twists usually cause lots more pain than Jade is experiencing now. The oil and analgesic should help break things loose within a couple of days. She doesn’t seem dehydrated yet, so I don’t think she would benefit from IV fluids,” I added.

While we were standing there, Jade started nibbling at some alfalfa that was on the floor of the stall.

“That’s my girl,” Susan said. “She never met a bale of hay she didn’t like!”

“You should keep a close eye on her throughout the rest of the day,” I warned. “The analgesic I gave her will wear off in about five or six hours. If she gets painful again, we’ll want to come up with a new plan.”

“What do you think could be causing this? She has never had colic before, why is it happening now?” Susan was afflicted with a psychosis common to horse people: denial.

“Good question. I wish I knew the answer.”

“Well, make something up!” she quipped. Susan was well aware of my tendency toward long-winded fabrications, which commonly ended with a shrug and an “I dunno.”

“I have an old veterinary textbook at home that was printed in 1897,” I started.

“About the time you graduated?” she interrupted.

“Don’t start on me now,” I joked. “I haven’t finished figuring up your bill!”

What I started to say to Susan was that, although there has been a lot of research on colic over the past century, we still don’t know too much about its actual cause. The obvious things still apply: internal parasites (worms), sudden feed changes, too much cold water after a hard work, and moldy feed can all bring on an episode of colic. Most of the time, as luck would have it, the inciting cause is unknown.

“Another of your famous ‘I dunnos’?”

“Exactly,” and I shrugged. “The treatments are about the same, too. Of course, surgery is an option nowadays in some cases, but we are still mostly limited to painkillers, intestinal lubricants, and intravenous fluids. The modern drugs tend to be a little safer than the old ones, but the idea behind the treatment hasn’t changed much in a long time. We won’t be able to completely prevent colic until we understand the exact cause.”

After a few days and several phone conversations between client and vet, Jade was back to her old, sweet self. Jade, like about eighty-five percent of the cases of colic I treat, responded to conservative medical treatment. The fact that it took so long for her problem to be resolved suggested that she had an impaction, but the exact cause will never be known.

This excerpt from Never Trust a Sneaky Pony by Dr. Madison Seamans is reprinted with permission from Trafalgar Square Books. You can purchase the book here.