Page 512 - Adams and Stashak's Lameness in Horses, 7th Edition

478 Chapter 4

junction that permits infection to invade the laminae,
which follows the path of least resistance to break open
VetBooks.ir may go undiagnosed until drainage at the coronary
and drain at the coronary band. However, the condition
band is observed. Signs of lameness may also vary
depending on the severity and location of the infection.

Diagnosis

A tentative diagnosis can often be made based on the
history and clinical signs. If pain is localized to the foot
but there are no obvious external abnormalities, the shoe
should be removed and the sole explored by removing the
exfoliating (flaky) sole with a hoof knife. Acute sole
bruises may not be readily apparent because the hemor-
rhage has not migrated far enough distally. Chronic
bruises are usually visible as a stippled reddened region.
31
In some cases the discoloration may be bluish, especially
if a sole abscess is developing. Sole abscesses may have a
small defect in the sole where the abscess is trying to
break through the sole. Alternatively, a large‐bore needle
can be inserted through the soft sole to confirm the pres- Figure 4.46. This horse with a type II P3 fracture became
ence of purulent material beneath (Figure 4.45). Removing acutely lame 2 months after diagnosis. A dorsopalmar radiograph
a small area of sole around this defect may also reveal demonstrated a fluid pocket (arrow) consistent with an abscess.
purulent material, confirming a subsolar abscess. Hoof
tester pressure at the site usually causes purulent material
to exit the sole defect. Focal swellings at the coronary not visible, depending on the radiographic projections, and
band (dorsally and at the heels bulbs) may suggest ascend- the lack of radiographic abnormalities does not rule out an
ing infections along the white line even when no defects abscess. Chronic sole bruising may be associated with dem-
can be detected on the solar surface of the foot. In these ineralization, increased vascular channels, and irregularity
cases, a definitive diagnosis often is not made until the of the solar margin of the distal phalanx. Chronic absces-
27
abscess breaks out at the coronary band. sation may be due to an underlying condition such as lami-
Acute sole bruises may not be evident radiographically nitis or keratoma and may contribute to osteolysis of the
unless a serum pocket or abscess has developed. Many sub- distal phalanx and sequestrum formation.
solar abscesses may be seen radiographically as a gas
pocket within the sole (Figure 4.46). However, many are Treatment
Many bruises often resolve without treatment if the
source of the trauma is removed. The horse should be
rested from heavy work, especially if the soles are abnor-
mally thin. When possible, the environment should be
changed so that the horse is not worked on rough
ground. If the horse must be used, the sole can be pro-
tected with a full pad applied under the shoe. The pad
should be placed to avoid pressure to the bruised site.
Wide‐web shoes may also be beneficial to relieve pres-
sure on the sole. Light paring of the sole overlying the
bruise often relieves the pressure and makes the horse
more comfortable. 25
Drainage is the key to treating suppurative bruises and
other subsolar abscesses. A small amount of sole overly-
ing the abscess should be removed to permit ventral
drainage. Removing a large amount of sole should be
avoided because this is usually not necessary for drainage
and prolongs the healing time. The foot can then be
soaked in antiseptic solution if desired, and the foot band-
aged. Once the abscess has resolved, the sole can be pro-
tected with protective boots or shoes until the defect has
completely keratinized. If an ascending infection of the
white line is suspected but cannot be confirmed (no drain-
Figure 4.45. This horse was non‐weight‐bearing lame with no age at the coronary band), soaking or poulticing the foot
evidence of a hoof abscess or fracture. Focal pain was detected may draw the infection to the surface. When the abscess
near the lateral heel and insertion of a 16‐gauge needle confirmed comes to a “head” just proximal to the coronary band,
the suspicion of an abscess. drainage can be established by lancing the abscess. 3,25,31