In this episode of Disease Du Jour, Emily Hellstrom, DVM, PhD, joined us to discuss her research on postoperative ileus in horses and improving postoperative outcomes for colic patients.
Postoperative Ileus in Horses
Postoperative ileus occurs when a horse’s gut motility doesn’t return after surgery at a normal rate. Hellstrom said 0-60% of horses experience some sort of ileus after their surgery procedures, which is comparable to human patients, who experience a 2-60% incidence rate of ileus after surgery.
Known risk factors for postoperative ileus in horses include small intestinal resection and anastomosis, old age, anesthesia time, and some drugs used after surgery. However, there is no definitive test to predict a horse’s risk of ileus prior to surgery, which is an area of research Hellstrom is interested in exploring further.
Treatment Options and Prognosis for Postoperative Ileus
“Unfortunately, the pathophysiology of how ileus works is really complex,” Hellstrom said. “We know that there’s a neurogenic or neuronal phase to it and an inflammatory phase. Our treatments are trying to focus on both aspects of that, mainly with the inflammatory right now.”
Current treatment options include flunixin meglumine and other non-steroidal anti-inflammatories after surgery to reduce inflammation. Hellstrom said lidocaine helps with patient comfort and could potentially help with motility. Walking horses can help stimulate motility if they aren’t in too much pain. She said human patients are often instructed to chew gum to help with ileus; putting a hay bag outside the horse’s stall can help stimulate some of the same receptors to get the gut moving.
“But overall, it’s very frustrating that we don’t have a cure-all for ileus,” she said. “A lot of our treatment is supportive care until their gut motility returns to normal.”
Overall, horses that have a small intestinal resection site that experience ileus are about 30 times less likely to survive to discharge than horses that don’t have ileus after surgery.
Ongoing and Emerging Research
Hellstrom has been actively involved with research on postoperative ileus in horses. In 2021, she co-authored the paper “Postoperative Ileus: Comparative Pathophysiology and Future Therapies.” She also completed a PhD at the North Carolina State University College of Veterinary Medicine, where her research focused on improving postoperative outcomes for colic patients. In 2022, Hellstrom received a grant from the Morris Animal Foundation to study postoperative ileus associated with colic. In the episode, she discussed some of the research with which she’s been involved.
Because ileus is a significant problem in human medicine, equine researchers have many tools already available to better understand how ileus works. Researchers understand that there’s an initial neurogenic shift in ileus; the parasympathetic, normal state of the intestine shifts to a sympathetic state, which is when the intestine is told not to move as much. However, researchers currently think the disease process is really propagated by the subsequent inflammation of the intestine wall. This inflammation brings inflammatory cells and their products, which reduce the intestine’s motility.
“That’s what we’re trying to target, trying to reduce that inflammation,” Hellstrom said. “If we can reduce it, either we can prevent ileus from happening, or we can make sure that ileus doesn’t go on for as many days as it normally would.”
The intestine has a single layer of epithelium cells that keep harmful bacterial products in the GI tract from entering the intestinal wall. Research has shown that the intestine is in an inflammatory state during colic surgery, which sets it up to have changes in the intestinal barrier function. These changes can lead to the high inflammatory phase and resulting complications.
Hellstrom has looked at specific cell types during her research, including enteric glia cells, which have been a focus of human medicine. These are sensing cells within the intestine that are activated during colic surgery. In other species, enteric glia cells release substances that can cause the intestinal barrier to become leaky.
While conducting research with the Morris Animal Foundation, Hellstrom worked on culturing these cells from equine intestines and exposing them to inflammatory compounds like interleukin-1 beta, which is present at the time of colic surgery. She saw that the cells produced substances that caused the equine intestinal cells to act leaky.
Now, Hellstrom is looking into biologics to prevent this from happening. Her recent work has hinted that putting serum, like IRAP, in the intestine with those intestinal cells can help prevent the leakiness caused by the sensing glial cells.
About Dr. Emily Hellstrom
Emily Hellstrom, DVM, PhD, is a clinical instructor at North Carolina State University, in Raleigh, North Carolina. After completing her undergraduate studies near Lexington, Kentucky, Hellstrom moved to Texas, where she obtained her veterinary degree at Texas A&M University. While in vet school, she enjoyed working with the equine practices in Weatherford, Texas, and also began visiting Ocala, Florida. This led to her completing a rotating internship at the Equine Medical Center of Ocala following graduation, allowing her to develop her skills as an emergency clinician in both the hospital and ambulatory setting on a wide array of breeds and disciplines. She most recently completed her PhD at the North Carolina State University College of Veterinary Medicine, with her research focused on improving postoperative outcomes for colic patients.
Related Reading
- Postoperative Reflux in Horses With Large Colon Volvulus
- Strangulating Lipomas
- Serum Amyloid A as Survival Predictor for Colitis in Horses?
Stay in the know! Sign up for EquiManagement’s FREE weekly newsletters to get the latest equine research, disease alerts, and vet practice updates delivered straight to your inbox.
