Page 668 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Respir atory system: 3.2 Surgical conditions of the respir atory tr act 643

VetBooks.ir ARYTENOID CHONDRITIS performance associated with a stridor-like inspira-
tory noise. The disease may have an acute onset or be
Definition/overview
This is an important cause of airway obstruction due chronic and insidiously progressive. The severity of
signs varies with the degree of damage and subsequent
to inflammation, thickening and distortion of the obstruction. In severe and bilateral cases clinical signs
arytenoid cartilage, leading to exercise intolerance may be evident at rest or walk. Coughing is common.
and an abnormal respiratory noise. It is diagnosed on
endoscopy. Medical treatment is sometimes effective Differential diagnosis
in mild cases. Partial arytenoidectomy is used in sur- Most of the other respiratory obstructions of the
gical treatment of more severe cases. racehorse, in particular RLN, will present with sim-
ilar noise and performance limitations.
Aetiology/pathophysiology
A progressive inflammatory process develops within Diagnosis
the corniculate process of the arytenoid cartilage, Endoscopic examination is diagnostic but requires
which, due to its limited blood supply, is difficult to care. Poor quality equipment or a casual examina-
resolve once established. The process leads to dis- tion can easily result in an incorrect diagnosis of
tortion of the cartilage, dystrophic mineralisation, RLN, particularly in a left-sided case of chondritis.
protruberances of damaged cartilage and/or infected There will be limited movement of the affected ary-
granulation tissue and fistula formation. The tracts tenoid cartilage, but further assessment will reveal
may drain mucopurulent material and there is swelling of the corniculate process, which may be
a decreased abduction of the affected arytenoid associated with mild rostral displacement of the
(Fig. 3.82). The cause is unknown but may include palatopharyngeal arch. The most reliable diagnos-
trauma to the cartilage and/or infection following tic feature of chondritis is a small discharging sinus,
mucosal damage. The condition is usually unilateral. usually on the axial border of the cartilage, which
is often associated with a granuloma (Fig. 3.83).
Clinical presentation A ‘kissing lesion’, a small reddened or ulcerated area,
The presentation is similar to other respira- is commonly identified on the contralateral cornic-
tory obstructions of the racehorse, notably poor ulate process (Fig. 3.84). Bilateral cases may have

3.82 3.83

Fig. 3.82 Chondritis of the right arytenoid Fig. 3.83 A granuloma on the left arytenoid cartilage,
cartilage. There is limited abduction, distortion of associated with minimal abduction and mild displacement
the corniculate process and a discharging sinus on the of the rostral palatopharyngeal arch. This horse had
axial margin. undergone a tie-back surgery 6 months previously.