Page 121 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

96 CHAPTER 1

VetBooks.ir cartilage or ipsilateral collateral desmopathy of the affected tissues can drain; severe if drainage is
poor and moderate to mild if the drainage is good.
DIP joint.
Management A draining wound may be the primary presenting
symptom. A history of trauma to the foot or other
If a primary condition can be identified, it should be foot lameness (e.g. abscess) is common.
treated as such. In those horses in which pedal oste-
itis is present, but no obvious primary disease can Differential diagnosis
be identified, symptomatic therapy is warranted. Severe lameness: abscess; fractured distal phalanx or
Symptomatic therapy usually consists of pain control navicular bone; other deep digital sepsis. Drainage:
with non-steroidal analgesics in conjunction with cor- abscess; other deep digital sepsis.
rective trimming and shoeing with seated-out wide-
webbed shoes and/or pads to diminish concussion on Diagnosis
the sole. Flat-footed horses with chronic foot soreness The cause of lameness is usually readily isolated to
and chronic remodelling of the distal phalanx may the foot, either because of the presence of a wound
require life-long attention to minimise concussion. and/or drainage or because of a marked withdrawal
response to hoof testers. Standard lateromedial, dor-
Prognosis sopalmar and dorsoproximal/palmarodistal oblique
The prognosis is related to the primary condition. In radiographic projections may need to be supple-
horses in which the primary condition is not obvi- mented with additional oblique views taken at vari-
ous, but the lameness is chronic and the conforma- ous angles to the median plane to identify septic
tion/balance is poor, the prognosis is guarded. osteitis of the distal phalanx (Figs. 1.167, 1.168).
Usually the radiological symptoms of septic osteitis
SEPTIC OSTEITIS OF THE of the distal phalanx are irregularly marginated areas
DISTAL PHALANX of lysis around the solar margin of the distal pha-
lanx, although occasionally, radiolucent cavities can
Definition/overview present within the substance of the bone. Sequestra
Infection of the distal phalanx. are identified as osseous radiodensities surrounded
by an area of lysis. Osteitis and sequestra of the pla-
Aetiology/pathophysiology num cutaneum of the distal phalanx may be difficult
Septic osteitis of the distal phalanx is usually caused to detect radiographically because of its concavity.
by a puncture wound to the sole or an extension of CT and MRI are very good at visualising fragments
an abscess. Sequestration of the distal phalanx may that may not be observed on plain radiographs. MRI
develop as the result of infection of a fragment of is useful to delineate early sequestrum formation,
bone, either as a consequence of a fracture occur- detect the presence of bone oedema in septic oste-
ring at the same time as the original trauma or sec- itis and identify tracts in the soft tissues of the foot
ondary to necrosis following loss of blood supply. In (Fig. 1.169). If there is persistent drainage from a
horses with laminitis, septic osteitis may also occur wound on the solar surface of the foot, but there is
as a sequela to infection of the lamellae and sole. If a no radiographic evidence of osteitis or sequestration
large portion of the distal phalanx is affected, patho- and neither CT nor MRI are available, then surgical
logical fractures may occur. Rarely, depending on exploration of the wound is appropriate.
the location of the infected bone, the infection can
spread to adjacent structures. Management
The treatment of septic osteitis of the distal pha-
Clinical presentation lanx, with or without sequestration, is open surgi-
Horses with septic osteitis of the distal phalanx cal drainage and debridement under local or general
usually present with lameness that varies in sever- anaesthesia. The wound is bandaged with a topical
ity depending on how well the exudate from the antimicrobial dressing, and the horse treated with