The earlier laminitis is recognized by the veterinarian or farrier, the earlier the vet/farrier team can develop a management plan together, and the better the potential outcome.
“The vast majority of laminitis cases are endocrine in origin and can be ‘simmering’ under the eyes of the owner, farrier, and veterinarian,” said Richard (Dick) Mansmann, VMD, PhD, Hon. Dipl. ACVIM-LA, owner of Equine Podiatry and Rehabilitation Mobile Practice, in Chapel Hill, North Carolina, during his presentation at the 2022 Northeastern Association of Equine Practitioners Vet and Farrier Conference, held in Saratoga Springs, New York, Sept., 21-24.
The farrier typically looks at the sole of the foot more than the veterinarian. Stretching of the laminae—the tissues that suspend the coffin bone within the hoof capsule—at the toe is something he or she might see, possibly with blood staining if that stretching is acute.
“Such stretching prompts podiatry radiographs,” said Mansmann. “These are critical for fully assessing the horse’s foot.”
Radiographs in Horses With Laminitis
He explained that podiatry radiographs are slightly different from traditional foot radiographs. In podiatry X rays, practitioners aim the radiographic beam at the shoe/hoof area, whereas in traditional foot X rays they direct the beam toward the coffin joint.
“This internal view of the foot shows the vet/farrier team how the hoof and shoe are mechanically relating to the coffin bone,” said Mansmann. Therefore, he added, it also guides them on how to improve the trimming and shoeing mechanics to prevent further laminar damage.
At the bare minimum, veterinarians/farriers need a lateral projection of each of the four feet.
“You always need a baseline image, rather than wishing you had one once you are in the thick of things,” Mansmann said. “Ideally, every horse owner has baseline podiatry radiographs of their horse so when some foot problem is identified it can be comparatively addressed.”
On the podiatry lateral radiograph, look for the slight radio dense line that is the border between the lamellar and horn zone—the H/L zone. This, he said, is where the inflammatory reaction occurs right next to the coffin bone.
“The H/L zone should be parallel to the face of distal phalanx, just like the exterior wall should be,” Mansmann said.
He provided two images to help describe this anatomy. Figure 1 shows a normal podiatry lateral radiograph with the lamellar zone shown equal at top and bottom via red lines and the horn zone equal top and bottom via white lines. Figure 2 is a podiatry radiograph of an endocrine-related laminitis case with the highly vascular lamellar zone showing chronic inflammation from top to bottom via red lines and the hard, nonvascular horn zone unchanged in thickness top to bottom via the white lines.
“When the lamellar zone is widening in a sound riding horse, this can be evidence of past or slowly occurring lamellar zone inflammation, which might then be called subclinical laminitis. This horse needs further evaluation,” Mansmann explained.
Steroids as a Laminitis Trigger
Subclinical laminitis can often be seen in an easy keeper with a body condition score greater than 6, which occurs relatively frequently these days, he noted. In these horses, the practitioner can see evidence of the coffin bone having rotated very slowly. If there is a trigger factor at some point, then subclinical disease can become clinical. For example, dexamethasone administration for a flare-up of equine asthma could be a trigger factor, resulting in acute-onset lameness a few days later. In a situation like this, Mansmann has seen a horse so lame the animal’s four feet were “locked to the floor.”
If the horse’s baseline radiographs were reviewed, Mansmann said we might see an increased H/L zone near the tip of the coffin bone that could represent a past inflammatory reaction.
Steroids could, in fact, be a trigger for laminitis in a variety of horses.
“Should the joints of a 12-year-old sport horses be injected with a steroid, especially if they have a body condition score of 7 or more? Will this be a triggering factor for laminitis? We don’t know,” said Mansmann.
What Vets and Farriers Should Do First in Laminitis Cases
He made the following recommendations for veterinary/farrier teams when first suspecting any foot pain that could remotely be laminitis:
- Evaluate the status of the case via podiatry radiographs as soon as possible. “I recommend leaving the shoes on to support the sole until after the first set of radiographs are taken and the vet/farrier team have made a plan. You can traumatize the foot if you keep pulling and replacing the shoes until you make a diagnosis, leaving no sole left on the horse to work with,” he said.
- Evaluate the trim needed for each specific case. For example, do you need to lower the heel, reduce breakover by trimming the toe, or both?
- Always manage the pain. “It is important to get the pain away as fast as possible. Unmanageable pain is a predictor of a bad outcome,” he said.
- Cushion the horse’s feet, he said, using Soft-Ride or other supportive boots. Such cushioning, along with the mechanics of the boot, allows the horse to put his foot where he wants it to be, allowing him to essentially relieve his own pain. Even Styrofoam, although old-fashioned, can cushion the horse’s feet. “The cushioning lets the horse ‘help’ manage their own case,” said Mansmann.
- Expect the horse to be on stall rest for a minimum of six weeks. And although horses will start responding in about two weeks, delay applying a permanent shoe.
- Test for equine Cushing’s disease and equine metabolic syndrome in laminitic horses over 7 years old.
Mansmann strongly recommended avoiding the six-week post-acute laminitis bout phenomenon.
“Within the first couple of weeks, the horse gets more comfortable,” he said. “He’s in a stall with deep shavings, the phenylbutazone has been able to be reduced, and the (low-sugar) diet is kicking in. The owner is pleased, and the vet and farrier are starting to breathe a little.
“Then the owner decides to give the horse a break and turn the horse out because he is doing so great,” he said. “The horse blasts out and is crippled when he comes back. You can’t just fix the horse again. In this situation (we) have a very grave prognosis. The healing laminar bonding had only partially occurred and got completely torqued apart during the blast of running of the fresh-feeling horse.”
With some parting words of wisdom, Mansmann advised looking at the whole horse that has laminitis, not just the two front feet. Protect the gastrointestinal tract while on phenylbutazone and wean off this non-steroidal anti-inflammatory drug slowly, maybe taking up to six weeks.
“It’s harder to get the pain cycle back under control if the phenylbutazone is stopped too early. It’s better to wean slowly,” he said.
Finally, in some cases the initial laminar damage is significant and puts the horse and his health care team on a roller coaster ride. In these cases the owner and their veterinary/farrier team need to put a hospice plan in place.
“Give the horse a dignified end of life,” Mansmann said.