Page 90 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Musculoskeletal system: 1.3 The foot 65

VetBooks.ir If the clinical signs fail to improve or the abscess Clinical presentation
Foot bruises may or may not be a cause of lameness.
recurs, then radiography should be performed.
If radiography does not indicate other pertinent
pathology, further exploration is warranted, which They can be identified when a horse is being trimmed
or shod and appear to be an incidental finding and
may include further removal of any underrun sole may indicate an underlying problem with conforma-
or wall. tion or foot balance. The lameness can be acute or
chronic, mild or severe, unilateral or bilateral. The
Prognosis latter is usually associated with a predisposing cause
The prognosis is good for simple abscesses that are such as poor foot conformation.
associated with neither a predisposing cause nor
infection of the deeper structures of the foot. If the Differential diagnosis
abscess is associated with a predisposing cause, then The clinical presentation is very varied and therefore
recurrent abscessation may be likely. If the infec- overlaps with almost any other disease of the horse’s
tion involves a deeper structure, the prognosis varies foot.
with the structure affected.
Diagnosis
BRUISING The site of a clinically significant bruise is usually
identified by applying hoof testers to the affected
Definition/overview area; this will elicit a withdrawal response. The
Bruises are an extravasation of blood from rup- bruise itself is identified when the foot has been
tured blood vessels into the surrounding tissues as a cleaned and pared (after the shoe has been removed
sequela to blunt trauma. if necessary) and the blood staining of the hoof
identified (Fig. 1.109). Occult, but clinically signifi-
Aetiology/pathophysiology cant, bruises may never be identified or may only be
Most bruises occur in the sole or the lamellae, identified when the haemorrhage has become more
although bruising may occur at the coronary band superficial with hoof growth. Suppurative bruises are
and in the frog. Bruises may be caused by a single identified in a similar manner to abscesses. Bruising
forceful contusion or recurrent lower-grade trauma. from the coronary band is visible in unpigmented
The former is likely to be an isolated incident. The horn of the wall as horizontal red stripes, but these
latter is commonly associated with a conformational are seldom clinically significant. Chronic bruising
or pathological predisposition such as flat feet or
laminitis. Alternatively, bruising can be caused by
pressure on the sole from poorly fitting shoes. Corns 1.109
(bruises in the angle of the sole) are almost invariably
associated with shoes that have been fitted too short
or shoes that have been on for too long and migrated
dorsally with toe growth. The extravasation of blood
into the tissues gives a bruise its characteristic dis-
colouration. In contrast to skin bruises, haemor-
rhage that occurs into the hoof capsule retains its red
colouration. The haemorrhage penetrates a variable
distance into the substance of the horn and appears
stippled to reflect the tubular nature of the horn. It is
not visible until the affected hoof reaches the surface
through normal growth. Bruises can occasionally
become infected through microfractures in the hoof Fig. 1.109 Extensive bruising of the dorsal sole
capsule. distal to the dorsal solar margin of the distal phalanx.