Laminitis in a Nutshell
Understanding
the Phases of Laminitis in the Horse
By Adam
Whitehead, Resident Farrier UFVMC
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Grossly
defined, laminitis is inflammation of the sensitive laminae
in the hoof of the horse, caused by stressful events, trauma,
infection, or parturition. This definition sheds little light
on the destructive process that occurs within the hoof. Laminitis
is commonly known as a secondary process and is a result of
a variety of primary processes. Some of the primary causes
that initiate laminitis are starch-overload, colitis, colic,
diarrhea, Cushing’s disease, retained placenta, exhaustion,
direct hoof trauma, excessive weight bearing on a single limb,
change in diet or environment, and stressful travel. Once
the laminetic process has begun it can be classified into
the developmental, acute, and chronic phases.
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Developmental
Phase
The developmental phase typically begins with the onset of
the primary process (e.g. hoof trauma or colic). Symptoms
such as elevated digital pulse and warmth in the hooves are
typically mild and generally present within 12-24 hours. Treatment
for horses in the developmental stage of laminitis should
be proactive, not reactive, and based largely on the probability
of the disease occurring. Most treatment goals are aimed at
eliminating the cause of the episode, preserving circulation,
and providing hoof support.
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Abscess
on the sole of a lamitetic horse. The PIII bone has penetrated
through the solar corium (tissue between the sole and PIII bone
of the foot) and has therefore pushed the sole outward in the
the center of the foot. |
Acute
Phase
The acute stage begins with the onset of pain and lameness,
typically within 24-48 hours, and lasts until the pain and lameness
subsides and the horse recovers or displacement (rotation, sinking
or both) of PIII (the distal phalanx) occurs. Horses in the
acute phase generally exhibit common signs such as, elevated
digital pulse, warm hooves and painful response at the toe to
hoof testers. Loss of appetite, limited intake of fluids and
the typical laminetic stance (transferring weight off of the
front hooves) are also commonly observed signs. In this phase
the inflammatory process is at its climax and blood supply to
the digit may be severely compromised. This hypoperfusion within
the digit may lead to ischemia, necrosis, and edema compromising
the integrity of the laminae. sential in establishing a baseline
for treatment as well as to monitor for displacement of PIII.
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| Aggressive
treatment during the acute phase generally provides a more favorable
outcome and may preserve the integrity of the laminae. Use of
non-steroidal anti-inflammatory drugs (NSAID’s) such as
Bute to control pain is a common practice. Treatment should
also target reducing the biomechanical forces that further compromise
weakened laminae. No system has been proven universally effective,
yet the goals are simple. Reduce the lever arm the toe creates;
apply heel elevation combined with caudal sole support and limit
the horse’s activity. Radiographic examination is also
essential in establishing a baseline for treatment as well as
to monitor for displacement of PIII. |
Same
horse after surgery to the deep digital flexor. The foot has
been de-rotated and a shoe has been glued on. A hoof wall reconstruction
has also been performed. |
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Chronic
Phase
The chronic phase begins when clinical or radiographic signs
of displacement are noted. This rotation and/or sinking of
PIII occur as a result of failed laminar bond, which suspends
the bone within the hoof capsule. This displacement compresses
the corium at the coronary band as well as under the tip of
PIII, resulting further compromised perfusion, abnormal hoof
function, and chronic pain. Treatment of chronic laminitis
is primarily based on therapeutic trimming and shoeing, while
continuing to control pain and the initial trigger. Goals
of therapeutic shoeing, aided by radiographs, are to restore
PIII’s orientation to the ground establishing proper
boney alignment and helping to restore normal function of
the hoof. Dramatically reducing the biomechanical exertion
of the deep digital flexor tendon (DDFT) is paramount to successful
treatment as well. These efforts allow new laminae to generate
as the hoof grows, eventually providing stability to PIII.
It is important, however, to note that the amount of damage
incurred during the early stages is directly related to how
well a horse will recover. Surgical interventions may include
a deep digital flexor tenotamy on horses that exhibit progressive
rotation despite interventions and/or on horses in which PIII
has or is about to penetrate the sole.
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| Side
view radiograph of a horse that has developed laminitis.
As you can see, the PIII bone has rotated and has basically
penetrated through the sole of the foot. This picture
is before any treatment was performed. |
Back
view radiograph of the same horse after therapeutic shoeing
and surgery were performed. |
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Treating laminitis at any stage can be emotionally trying
for all involved. Awareness by owners, veterinarians and farriers
of horses that are high risk as well as early diagnoses and
treatment according to the probability the disease occurring
rather than waiting for laminitis to occur may certainly provide
the most favorable outcome. It is also important to recruit
a vet/farrier team that keeps realistic goals in mind such
as, maintaining comfort of the horse, preserving and/or restoring
adequate perfusion to the hoof and reducing the biomechanical
influence of the DDFT.
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Adam
Whitehead is the resident farrier at the University
of Florida Veterinary Medical Center. Whitehead completed
farrier school in Tennessee and studied animal science
at Abraham Baldwin Agriculture College in Tifton, Ga.
Prior to joining the UF team, Whitehead successfully
practiced in the field for 10 years. |
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