Page 659 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

634 CHAPTER 3

VetBooks.ir DORSAL DISPLACEMENT OF THE 3.70
SOFT PALATE – PERMANENT

Definition/overview
Permanent DDSP is less common than the intermit-
tent form and caused by either physical or neuro-
logical abnormalities. Clinical findings can include
respiratory obstruction and/or noise, exercise intol-
erance, dysphagia and coughing.

Aetiology/pathophysiology
There are multiple causes of permanent DDSP,
which can be divided into physical and neurologi-
cal. Permanent DDSP can be caused by physical
obstruction of the subepiglottic space including
subepiglottic cysts, palatal cysts, foreign bodies and
even severe pharyngeal lymphoid hyperplasia. It can
also be associated with neurological abnormalities,
in particular pharyngeal paralysis, the most com-
mon cause of which is guttural pouch mycosis.
Fig. 3.70 Permanent dorsal displacement of the soft
palate. The apparent swelling is the outline of the
Clinical presentation epiglottis underneath the palate.
Permanent DDSP is usually associated with marked
respiratory stertor at exercise, including at trot or even
walk. Performance is usually markedly affected – soft palate in a subepiglottic position in most normal
most horses are unable to canter due to respiratory horses (Fig. 3.71). If permanent DDSP is identified,
obstruction. Pharyngeal phase dysphagia is another then endoscopy of the guttural pouches is indicated.
frequent feature leading to coughing during eating Endoscopy of the oropharynx is also frequently indi-
and nasal return of feed material and saliva. cated; however, consideration needs to be given to
restraint for this procedure to prevent trauma to the
Differential diagnosis endoscopic equipment (Fig. 3.72). The diagnosis can
As a finding rather than a disease there is no specific also be confirmed by radiography. This allows iden-
list of differential diagnoses. Some relevant condi- tification of the soft palate dorsal to the epiglottis.
tions include cleft palate and palatal hypoplasia in It may also allow identification of soft-tissue masses
the foal, and oesophageal obstruction (choke) in the ventral to the epiglottis, causing physical DDSP.
adult horse. The most important neurological cause
is guttural pouch mycosis. Management
Management depends on identification of specific
Diagnosis aetiology – for instance, management of guttural
Diagnosis is usually established by endoscopic pouch mycosis or resection of subepiglottic cysts.
examination. DDSP is observed and the palate is not In some cases when a specific cause is not identified
replaced in a subepiglottic position despite stimula- and the condition proves to be permanent despite
tion of deglutition on several occasions (Fig. 3.70). management with anti-inflammatory and antibiotic
Care should be taken as some horses will show treatment for a prolonged time, the symptoms can
DDSP as a response to endoscopy. However, patient be relieved by staphylectomy surgery. The ‘tie for-
observation, with the scope withdrawn as far into ward’ surgery has also been used with some success,
the nasopharynx and as far away from the larynx as and indeed has been combined with staphylectomy
possible, will normally result in replacement of the with good results.