equis - Articles
Pharynx: collapse
Introduction
- Cause: idiopathic dynamic obstruction of the upper respiratory tract due to collapse of the nasopharyngeal walls during exercise, obstructing air flow.
- Signs: inspiratory noise, reduced performance.
- Diagnosis: signs, endoscopy.
- Treatment: none.
- Prognosis: fair to guarded.
Presenting signs
- Inspiratory noise during exercise.
- Reduced performance.
Geographic incidence
- Worldwide.
Age predisposition
- Young: 2-3 years.
Breed/Species predisposition
- Thoroughbred Thoroughbred.
- Standardbred Standardbred.
Cost considerations
- Cost of treatment or inability to perform at expected level.
Pathogenesis
Etiology
- Idiopathic.
- Damage to pharyngeal innervation, eg following guttural pouch infection Guttural pouch: empyema.
Predisposing factors
Specific
- Damage to phyarngeal innervation, eg following guttural pouch infection.
Pathophysiology
- Neuromuscular disorder of pharyngeal musculature.
- Neuromuscular fatigue of the tensor veli palatini plus strong negative inspiratory pressures during fast exercise → pharyngeal collapse → airway obstruction → reduced performance and respiratory noise.
- May be exacerbated by head/neck position.
Timecourse
- Acute to chronic.
Diagnosis
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Treatment
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Prevention
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Outcomes
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Further Reading
Publications
Refereed papers
- Recent references from PubMed and VetMedResource.
- Franklin S H (2008) Dynamic collapse of the upper respiratory tract: A review. Equine Vet Educ 20 (4), 212-224 VetMedResource.
- Petsche V Met al (1995) Effect of head position on upper airway function in exercising horses. Equine Vet J Suppl 18, 18-22 WileyOnline.
- Smith C M, Taylor R J & Dixon P M (1994) Unilateral ventral displacement of the roof of the nasopharynx as a cause of stridor in a pony. Vet Rec 134 (6), 140-141 PubMed.
Other sources of information
- Parente E J (1998) Dynamic obstruction of the pharynx. In: Proc World Equine Airway Symposium.
- Parente E J (1995) Correlation between standing endoscopic examinations and those made during highspeed exercise in horses - 150 cases. In: Proc Am Assoc Eq Pract. pp 170.