Abscess
Definition
An abscess
in an infection & inflammation within the horny foot that can cause acute
lameness due to the pressure build up from the formation of puss with or
without gas pockets.
There are 2
types of abscess.
Sub
Solar Abscess -
A sub solar
abscess in an infection between the horny sole and sensitive sole
Laminal
Abscess (Sub Mural) -
A laminal
Abscess is an infection between the horny wall and the sensitive lamina (dermal
laminae)
Anatomy
The
anatomical structures involved with Abscesses are
The
Horny Sole
The
Horny Wall
Sensitive
Sole
Sensitive
Laminae
White
Line
Causes
Common Cause
of Abscesses are
Solar
penetrations by foreign object
Sole
Pressure
Suppuration
Corns
Fractures
Nail
Prick
Laminitis
Clinical
Signs
There will
be a variable degree of lameness depending on the size of the abscess and the
amount of pressure being places on the sensitive structures caused by the
underlying infection, this can be a mild lameness to a no weight bearing limb.
There will
be heat within the foot and swelling around the coronary bend and fetlock due
to the infection, a strong digital pulse can also be felt over the
Medial/Lateral digital arteries. In the
later stages of infection there will be a pungent smell from the foot and the
possibility of sinus tracts on the sole or horny wall.
With Sub
Mural abscesses the infection can track up the horny wall and erupt out of the
coronary band causing a interruption in the hoof wall production and will
travel distally as a horizontal crack.
Diagnosis
The
Diagnosis of an abscess is first done by examining the foot for penetrations
and light pairing of the sole, most of the time there can be obvious sinus
tracts that will shoe as a black puss coming out of the sole. If an abscess is
present the a pungent smell can also be smelt when examining the foot.
light
palpitation of the foot by hand looking for a pain response, and the careful
use of hoof testers is also a good way of finding the exact area of infection.
light exploration can be carried out and if a high pressure tract is relived
the puss will spurt out and an immediate relief can be seen by the horse.
if the
abscess is from a nail prick then the use of hoof testers on each clench will
show signs of a pain response on the offending nail, when the nail is removed
then a black smelly puss can be seen on the nail shank.
if the horse
is acutely lame but no abscess can be found after light pairing of the sole
then the use of a poultice to soften the feet and dray the infection out can
help speed up diagnosis
Treatment
Farrier Treatment
Once an
abscess is located then it can be drained by the use of a hoof knife, (searcher
knives are useful as they allow for very accurate work ) this will relive the
pressure build up within the foot and allow for the abscessation area to be
cleaned.
The use of
Hydrogen Peroxide can be advantageous due to the foaming action and the high
oxygen content. then the tract can be cleaned with a dilute povidone solution
or soluble metronidazole,
Hot tubing
of the foot twice a day with a saturated solution of salt or Epsom salts can be beneficial for horses with multiple
tracts of infection. then use of a hot poultice for 12-24h after will ensure
all the infection is removed, a dry poultice can then be used to allow the foot
to harden and also protect the area from re-infection
Shoes
When the
tract has stopped draining then a well fitted wide webbed shoe that has been
seated out will allow for good support of the foot and protect the remaining
horny foot, the use of pads can be useful in some cases to protect the sole
from re infection. however there is still a risk of re infection from
contaminates becoming trapped between the healing sole and the pad. The ricsk
of re infection can be reduced by using a solar packing material.
Veterinary
Treatment
A vet will
be able to administer Non-Steroidal Anti-Inflammatory drugs that will help
reduce the amount of inflammation and help reduce excessive loading on the
other limb. antibiotics are not normal
given for an abscess that is not draining as this can extend the time it takes
for the infection to erupt , but if it is thort that the infection is close to
the distal phalanx then they can be used to protect then underlying structures.
Prognosis
An excellent prognosis can be given in the majority of cases
and the horse can return to steadily be normal work. But horses with poor foot
quality can be prone to reassurance.
