Esophageal and gastric disorders in the horse

What mechanical disorders can lead to a horse presenting with difficulty swallowing?

Persistent entrapment of the epiglottis, pharyngeal mass, tongue foreign body, tongue base neoplasia, severe temporohyoid osteoathropathy

What anatomical abnormalities can lead to a horse presenting with difficulty swallowing?

Palatoschisis

What disorders can lead to a horse presenting with difficulty swallowing that are neurologic in origin?

Guttural pouch mycosis, guttural pouch neoplasia

What are clinical signs of dysphagia caused by mechanical disorders?

‘Gagging’ and neck stretching when attempting to swallow, nasal regurgitation of feed, slow feed consumption, particularly slow to eat forage

What diagnostic investigations should be done when investigating dysphagia related to a mechanical disorder?

Oral exam, palpate retropharyngeal region, palpate esophagus, can a stomach tube be passed?

Consider endoscopy of URT and guttural pouches, endoscopic visualization of swallowing mechanism

Is pharyngeal sensation and response to stimulation normal?

How can you determine that a horse has glossitis as the cause of its dysphagia?

Slow chewing and deglutition,

Ddx tongue foreign body, tongue squamous cell carcinoma, sialolith

Radiography/CT to determine extent of damage, histopathology to rule out neoplasia (sample several sites)

How can you manage a horse with glossitis?

Debridement and lavage, topical systemic metronidazole

How can you determine that a horse has temporohyoid osteoarthropathy as the cause of its dysphagia?

Slow chewing + deglutition, may be CN VIII involvement

Distinct endoscopic appearance, decreased joint movement seen, radiography.CT to determine extent

How can you manage temporohyoid osteoarthropathy?

Conservatively, or consider ceratohyoidectomy

What are features of palatoschisis?

Varying grades, neonatal presentation or at weaning

See difficulty nursing, aspiration pneumonia may present

Some survive into adulthood, may just leak water down nostrils

Epiglottis rests on tongue

What is the definition of cleft palate (palatoschisis)?

A disorder resulting from embryonic palatal folds failing to fuse properly (usually the caudal 1/2-2/3 of soft palate most commonly effected)

Can affect both hard and soft palate

What are features of a horse that has damage to its glossopharyngeal nerve as the cause of its dysphagia?

Chronic nasal discharge and slow ingestion, concurrent aspiration pneumonia may occur, intermittent epistaxis

Can result from guttural pouch mass or mycosis

Prognosis is variable

When is the prognosis guarded in relation to glossopharyngeal nerve damage?

When it results from mycosis concurrent with internal carotid artery and CN IX damage

What are features of equine grass sickness (aka equine dysautonomia)?

Ptyalism, dysphagia, and retrogradal peristalsis in acute presentations

Damage to enteric plexus plus cranial nerve nuclei

Can lead to longitudinal esophageal ulceration

What may be seen in a patient with a longitudinal esophageal ulceration as a result of acute grass sickness?

Prolonged gastroesophageal reflux, may occur with gastric outflow obstruction, extreme pain on passage of nasogastric tube

What are features of simple esophageal obstruction (‘choke’)?

Most commonly seen after feeding, COMMON CONDITION, bilateral nasal regurgitation of feed and saliva

Gagging/retching/neck stretching behavior, often accompanied with coughing due to inhalation

How can you diagnose a horse with choke?

Feed material in green nasal discharge, resentment of cranial esophageal palpation (may be obvious swelling), resistance to passage of nasogastric tube, attempts to eat followed by coughing

How can we manage a horse with choke?

Heavy sedation and lavage via nasogastric tube, sedation → head drop → helps with drainage

Most common sites of obstruction: dorsal esophagus, thoracic inlet, cardia

Aim to gently lavage under sedation: feed material exits via opposite nostril

May not be possible to clear entirely, try again in a few hours (leave horse in water only, remove feed and bedding

Broad spectrum antibiotics, NSAIDS to decrease pain, maintain on soft diet for 7 days post relief of obstruction

How can you manage a dorsal esophageal obstruction?

More difficult to pass stomach tube, heavy sedation may promote drainage, insufflation often useful, reassess pharynx and esophagus endoscopically, evaluate lungs for aspiration/pneumonia (cranioventral/caudoventral lung)

What are potential complications of choke?

Deep ulceration or circumferential mucosal damage

What are features of deep ulceration as a complication of choke?

Linear ulceration can precede rupture, potentially see subcutaneous emphysema

What are features of circumferential mucosal damage?

More likely to result in stricture formation

How can you manage complications of choke?

Sucralfate and omeprazole to minimize acidic reflux, dietary management (mucosa/submucosa may recover diameter after 60d management), complete hay replacement ration

Serial bougienage for fibrous strictures

What are differential causes of a secondary esophageal obstruction?

Pulsion diverticulum, traction diverticulum, stricture formation (following neck injury or following choke), persistent right aortic arch

How can we diagnose a secondary esophageal obstruction?

Endoscopic examination following clearance of choke with insufflation

Contrast radiography may be required

How can you manage secondary esophageal obstruction?

Depends on cause: pulsion vs traction, surgery more likely to be required for full thickness mural cicatrix

What clinical signs may be seen in recurrent esophageal obstructions → dilatation?

Recurrent bouts of choke depending on size of diverticulum, tends to deteriorate with age in congenital cases due to poor wall tone

How can we diagnose recurrent esophageal obstructions → dilatation?

Endoscopy, double contrast esophagram, radiographic investigation of aspiration

How can we manage recurrent esophageal obstructions → dilatation?

Cervical pulsatile diverticuli can be repaired surgically, can empty manually in some horses, dietary management only for larger diverticuli at thoracic inlet

What are clinical signs of esophageal strictures?

Regurgitation of ingesta and saliva, may be history of neck trauma/bite

How can we diagnose an esophageal stricture?

Endoscopy, double contrast esophagram to determine length of lesion

How can we manage esophageal strictures?

Full thickness lesion requires esophagomyotomy to release mucosa

Endoscopic assessment during surgery to determine success

Reintroduction to soft diet for 10 days, then resumption of forage. Monitor for adhesions/further adhesions

How can you surgically correct an esophageal stricture?

Longitudinal esophagomyotomy → separation of outer and inner layers of esophageal wall, tube passed during surgery to ensure wide enough space

What are clinical signs of a cervical esophageal rupture?

Swelling and pain at site, may be a draining tract, SQ emphysema, cardiorespiratory compromise if mediastinitis

How can we diagnose cervical esophageal rupture?

Contrast esophagram, may release feed material if debriding

How can we manage cervical esophageal rupture?

Immediate establishment of drainage to prevent mediastinitis, surgical debridement is essential, placement of tube orally or tube esophagostomy ventral to site

Monitor for sepsis, treatment of local cellulitis

What clinical challenges do we have when managing cervical esophageal ruptures?

Maintenance of nutrient intake and electrolyte balance, concurrent aspiration pneumonia can occur, management of cellulitis, possible endotoxemia (and/or laminitis), severe emphysema

What complications may occur when managing cervical esophageal ruptures?

Can succumb to endotoxemia, recurrent choke is likely, may be laryngeal hemiplegia due to sympathetic trunk damage

Prognosis: guarded

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