Diagnosing and treating the neonatal foal
Upper airway endoscopy, tracheotomy, radiography and chemistry profiles effective diagnostic tools
Mar 01, 2006
Differential diagnosis for dysphagiaThe differential diagnoses for dysphagia in the foal are many and can include: dorsal displacement of the soft palate, rostral displacement of the palatopharyngeal arch, cleft palate, subepiglottic and pharyngeal cysts, bilateral laryngeal paralysis and arytenoid chondritis.
In a study of 38 foals with milk regurgitation/upper airway problems, 34 percent presented with dorsal displacement of the soft palate (DDSP). DDSP can be seen alone or in conjunction with rostral displacement of palatopharyngeal arch, redundancy of the soft palate or a persistent epiglottal frenulum. Prematurity, perinatal asphyxia and white muscle disease (nutritional myodegeneration, NMD) can be risk factors for the development of DDSP. In a review of 29 cases of NMD in foals, 52 percent of the foals presented with dysphagia as one of the clinical signs. Cerebral or brain stem disease may also influence the ability to swallow.
Unlike in humans where orofacial clefts, congenital fissures in the median line of the palate, are a common birth defect, cleft palate in the foal is very rare. The heritability of the cleft palate in the horse is unknown. The milk regurgitation is noted during the first nursing bout.
Subepiglottic and dorsal pharyngeal cysts also can interfere with the swallowing mechanism in the foal and cause upper-airway obstruction. These cysts are thought to originate from the thyroglossal and craniopharyngeal ducts, respectively.
Bilateral laryngeal paralysis and arytenoid chondritis have also been recognized in the newborn foal. Clinically these foals presented with respiratory distress. Laryngeal paralysis has been associated with cerebral diseases, such as congenital hydrocephalus. Arytenoid chondritis appears as an enlargement of the arytenoid cartilage and may mimic laryngeal paralysis.