equis - Articles
Epiglottis: persistent frenulum
Introduction
- Cause: congenital band of tissue on the ventral aspect of the epiglottis to tongue.
- Signs: young foal with nursing difficulties - dysphagia, oronasal reflux, cough; aspiration pneumonia - tachypnea, pyrexia, weakness.
- Diagnosis: endoscopy.
- Treatment: surgical transection of the frenulum.
- Prognosis: good with early diagnosis; poor with advanced pneumonia.
Presenting signs
- Nursing/suckling difficulties from birth.
- Respiratory distress.
- Oronasal reflux.
- Coughing after nursing.
Acute presentation
- Nursing/suckling difficulties from birth.
- Respiratory distress.
- Oronasal reflux.
- Coughing after nursing.
Geographic incidence
- Few case reports.
- Worldwide.
Age predisposition
- <1 week old.
Breed/Species predisposition
Cost considerations
- Surgical correction.
Special risks
- Secondary aspiration pneumonia may increase anesthetic risk.
Pathogenesis
Etiology
- Larynx is formed from several embryonic structures:
- Mucosa - endodermal.
- Cartilage and muscles - mesenchymal (within 3rd, 4th and 5th branchial arches).
- There are several embryonic processes that may contribute to frenulum formation:
- During proliferation of the laryngeal epithelium there is temporary occlusion of the lumen, then vacuolization and recanalization reforms the lumen.
- The epiglottis and the caudal portions of the tongue are formed from the hypobranchial eminence of the 3rd and 4th branchial arches; the epiglottis and tongue then gradually migrate apart.
- A variation in the closure of the thyroglossal duct (cf subepiglottic cysts Epiglottis: cyst - subepiglottic ).
- Fibrosis of the glossoepiglottic fold and hyoepiglotticus muscle.
- Note that membranous pharyngeal and laryngeal bands reported in humans do not resemble the epiglottic frenulum in foals.
Pathophysiology
- Persistent band of fibrous tissue from epiglottis to base of tongue → prevents normal action of epiglottis during swallowing → dorsal displacement of soft palate → aspiration and reflux of milk during nursing.
- Aspiration of milk → pneumonia.
Timecourse
- Clinical signs evident in first few days of life.
Diagnosis
Subscribe To View
This article is available to subscribers.
Try a free trial today or contact us for more information.
Treatment
Subscribe To View
This article is available to subscribers.
Try a free trial today or contact us for more information.
Prevention
Subscribe To View
This article is available to subscribers.
Try a free trial today or contact us for more information.
Outcomes
Subscribe To View
This article is available to subscribers.
Try a free trial today or contact us for more information.
Further Reading
Publications
Refereed papers
- Recent references from PubMed and VetMedResource.
- Dixon P M & Collins N (2004) The equine epiglottis. Equine Vet Educ 16 (6), 299-301 VetMedResource.
- Yarborough T B et al (1999) Persistent frenulum of the epiglottis in four foals. Vet Surg 28, 287-291 PubMed.