Page 89 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

64 CHAPTER 1

VetBooks.ir 1.106 Diagnosis
One foot may be palpably warmer than the oth-
ers, and application of hoof testers nearly always
induces a marked withdrawal response. Exploration
of the ground surface of the foot may or may not
reveal dark discolouration of the horn, indicat-
ing a track or injury site through which bacteria
may have entered. Further exploration of the track
should expose the abscess (Fig. 1.106). Perineural
analgesia with an abaxial sesamoid block is useful
to facilitate exploration of the hoof. When no track
1.107
is visible, but the symptoms are otherwise strongly
suggestive of an abscess, further exploration may be
warranted, although excessive paring of the foot is
contraindicated. If exploration still fails to identify
an abscess, the hoof capsule should be poulticed for
24–48 hours to soften the horn. The softer horn
makes the capsule easier to explore, and the abscess
may drain spontaneously, frequently at the coro-
nary band (Fig. 1.107). If the pain still persists and
an abscess cannot be identified, the foot should be
radiographed to exclude other causes of acute foot
lameness or detect gas pockets.
1.108
Management
Drainage is the primary treatment for hoof
abscesses and may be facilitated in difficult horses
by using regional nerve blocks and/or sedation.
Usually, a small hole, approximately 1 cm in diam-
eter, will suffice to drain the abscess regardless of
the area of stratum corneum that has been under-
run. If the abscess is adjacent to the white line,
Figs. 1.106–1.108 (1.106) Abscess drainage draining the abscess through a small notch in the
immediately inside the white line after exposure with distal wall is preferable to creating a hole in the
a hoof knife. (1.107) A probe demonstrates the tract sole because deficits in the latter are more difficult
created by an abscess that spontaneously drained at to manage. Bandaging the foot with an antiseptic
the coronet. (1.108) Cornification of the sole of the dressing is required for a few days, but repeated
horse in 1.106, 4–5 days after abscess drainage and poultices or foot soaking is not usually indicated.
dressing with povidone–iodine solution. Systemic antibiotics are not required unless the
abscess has extended deep to the dermis, but teta-
nus prophylaxis is mandatory in horses without
Differential diagnosis a recent history of vaccination. Once drainage is
Any disease of the foot associated with acute onset of established, the clinical signs should decrease rap-
severe lameness in a single limb; fracture of the dis- idly. The abscess wound should be dry within a
tal phalanx or distal sesamoid bone (navicular bone); few days (Fig. 1.108). If the abscess was drained
sepsis of a deep digital structure; severe bruising; through the sole, the horse can return to athletic
severe injury to a ligament or tendon within the foot. activity sooner by shoeing with a full pad or plate.