Page 95 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

70 CHAPTER 1

VetBooks.ir Clinical presentation lameness may manifest as an extremely stiff, short-
striding gait. Some acutely laminitic horses land
The initial presentation for horses with laminitis
may be quite variable. Many cases present with an
chronically affected horses, have a heel-before-toe
acute lameness, and in such instances the disease toe first, but the majority of acute cases, and more
is typically bilateral. Both forefeet are most com- landing position of the foot. When the forelimbs
monly affected, but any combination of feet is pos- only are involved, they may be placed out in front of
sible (Fig. 1.114). It may be difficult to tell whether the horse and the hindlimbs are thrust underneath
forelimbs, hindlimbs or all four limbs are affected. the horse’s body. More severely affected horses are
In horses with bilateral forelimb involvement, the reluctant to move or pick up a foot that is contra-
lateral to an affected limb; in the worst cases they
become persistently recumbent.
1.114 Other horses may show a more insidious onset of
the disease, such as many horses with insulin resis-
tance. While the symptoms are generally of the
same nature as those for horses with acute disease,
they are initially milder, less characteristic of the
acute disease and may mimic other common causes
of bilateral foot soreness. They may persist as more
subtle changes or they may progress. The course of
the disease is often prolonged and, therefore, there
may be visible changes to the hoof capsule at the ini-
tial presentation (Fig. 1.115). Alternatively, horses
may have a prior history of laminitis and present
with a more recent acute episode, gradual deteriora-
Fig. 1.114 A pony with forelimb laminitis exhibiting tion of chronic disease or with a complication such
the typical stance, with the forelimbs stretched out as hoof bruising or abscesses.
forwards and the hindlimbs placed underneath the Animals displaying moderate to severe lameness
body. (Photo courtesy Graham Munroe) at rest in a stall in one limb can present with sup-
porting limb laminitis in the opposite, initially non-
lame, limb. It is an event that should be anticipated
1.115
but cannot be predicted with any accuracy because
symptoms can develop either while a horse is mark-
edly lame in one limb, occur some time after symp-
toms appear to have abated in the lame limb, or not
occur at all. While the disease may have been pro-
gressing subclinically, it has a tendency to present
acutely. The first symptom may be increased weight
bearing by the primary lame limb.

Differential diagnosis
Acute laminitis is almost unique, although it must
be distinguished from diseases that make a horse
move stiffly such as colic, pleuropneumonia and
rhabdomyolysis.
Chronic laminitis must be differentiated from:
Fig. 1.115 A chronic laminitic foot with long toe, (1) diseases causing bilateral chronic forelimb lame-
dorsal compression of the hoof wall and hoof-ring ness (e.g. pedal osteitis, navicular disease, osteoar-
formation. (Photo courtesy Graham Munroe) thritis [OA]); and (2) diseases that cause similar hoof