Page 97 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

72 CHAPTER 1

VetBooks.ir 1.118 1.119

Fig. 1.119 Lateral radiograph of a chronic laminitic
foot with subtle bony remodelling of the tip of the
Fig. 1.118 Horizontal dorsopalmar radiograph of a distal phalanx (arrow). (Photo courtesy Frank Nickels)
chronic laminitic foot with medial distal displacement
of the distal phalanx.

require regional analgesia to confirm that the lame- polymyxin B and anti-endotoxin hyperimmune serum
ness is in the foot; depending on whether most pain is or plasma as appropriate. When the risk of the disease
arising from the sole or lamellae, the lameness should is high it is also advisable to remove the shoes and pro-
improve with palmar digital or abaxial sesamoid vide some form of sole support (see Acute laminitis,
nerve blocks, respectively. Radiographic evidence of below). Standing a horse in a slurry of ice and water
laminitis may also include lipping of the dorsal solar up to the level of the distal carpus/tarsus, during the
margin of the distal phalanx (Fig. 1.119) and evidence developmental and early acute stages of the disease,
of periosteal new bone formation on the dorsal pari- is the most effective treatment currently available to
etal surface of the distal phalanx midway between the reduce the severity of lamellar pathology. While the
extensor process and the dorsal solar margin. optimal duration for employing cryotherapy prophy-
lactically to the feet has not been definitively deter-
Management mined, it needs to be applied continuously. Currently,
The treatment of laminitis varies with the stage of if it is performed in high-risk horses that have not yet
the disease and can therefore be divided into pro- developed the disease, it should be continued until
phylactic measures, treatment of acute laminitis and the high-risk period is passed (typically 2–5 days).
treatment of chronic laminitis, although there is Complications can occur with cryotherapy, but they
some gradation from treatment of the acute, through are not common. Exposure to moisture can predis-
the subacute to the chronic stage of the disease. pose to dermatophilosis and, occasionally, frostbite
Prophylactic measures are titrated against the occurs if the skin is in prolonged direct contact with
risk of developing laminitis. The precipitating cause ice colder than 0° Celsius.
should be removed whenever possible (e.g. by taking
the horse off lush pasture). Additionally, primary dis- Acute laminitis
eases frequently associated with endotoxaemia and The treatment of acute laminitis is a combination of
laminitis should be treated to limit systemic absorp- medical therapy and supportive care, although the
tion and the effects of toxins that may precipitate former is the mainstay. Medical therapy is aimed at
the disease (e.g. horses that have ingested excessive limiting injury to the lamellae by intervention based
amounts of grain should be treated with mineral oil on the pathophysiology of the disease. Although no
and flunixin meglumine). Horses with endotoxaemia medical therapy has been unequivocally proven to be
should receive appropriate medical therapy includ- of benefit, systemic treatment with phenylbutazone
ing antibiotics, anti-inflammatory drugs, fluids, (2.2–4.4 mg/kg i/v or p/o q12 h) is probably the most