Lesson 82b - Equine Esophageal Disease

What are the characteristics of the equine esophagus?

1. 2-4 feet long

2. Upper 2/3 striated muscle

3. Lower 1/3 smooth muscle

4. Strong cardiac sphincter

What is an esophageal obstruction called in horses?

choke

What should a normal endoscopic view of the esophagus look like?

should be collapsed

What could an open esophagus seen on endoscopy indicate?

megaesophagus

Describe this endoscopic view of the esophagus.

normal

Describe this endoscopic view of the esophagus.

abnormal

What is the most common clinical sign of esophageal disease in horses?

ptyalism

What would be your top differential with this horse?

choke

What would be your top differential with this horse?

slaframine intoxication ("slobbers")

What are the differential diagnoses of ptyalism in horses?

1. Cranial nerve dysfunction

2. Foreign body (rare)

3. Poor dentition

Damage of which cranial nerve would cause a lack of prehension?

facial (VII)

Damage of which cranial nerves would cause problems with mastication?

1. trigeminal (V)

2. facial (VII)

3. hypoglossal (XII)

Damage of which cranial nerves would cause difficulty swallowing?

1. glossopharyngeal (IX)

2. vagus (X)

What are the diseases of the guttural pouch?

1. bacterial empyema

2. fungal mycosis

3. tympany in foals

What are the clinical signs of guttural pouch disease?

1. nasal discharge

2. noisy breathing

3. swelling behind the jaw

What is the most dangerous guttural pouch infection?

fungal

Why are fungal guttural pouch infections the most dangerous?

can erode arteries and cause life-threatening nosebleeds

How is guttural pouch disease diagnosed?

endoscopy

What is the treatment for guttural pouch disease?

flushing and antibiotics +/- surgery

How common are cleft palates seen in foals?

rare

What are the clinical signs of a cleft palate?

1. milk reflux from nostrils

2. rattle in trachea

3. coughing, abnormal lung sounds, tachypnea, tachycardia, and pyrexia from aspiration pneumonia

How is a cleft palate diagnosed?

oral exam and endoscopy

What should be ruled out before considering esophageal disease?

1. Oral cavity abnormalities

2. Guttural Pouch abnormalities

3. Cranial nerve abnormalities

What are the differential diagnoses for esophageal disease?

1. Esophageal obstruction "choke"

2. Esophagitis (reflux associated)

3. Esophageal perforation, stricture, or diverticula

4. Motility disorders of the esophagus like megaesophagus

5. Congenital disorders (rare)

6. Neoplasia (rare)

What are the clinical signs of choke?

1. Frothy nasal discharge

2. Feed from nostrils and mouth

3. Ptyalism

4. Gagging or retching

5. Coughing

What is a very important part of diagnostic evaluation of choke?

sedation with an alpha 2 agonist like xylazine to provide sedation and analgesia while keeping the head lower than the point of the shoulder

Why is it important to keep the head lower than the point of the shoulder with choke?

help gravity get the food out and prevent aspiration that can occur if the head stays high

How is choke diagnosed?

1. Endoscopy

2. Nasogastric tube

3. Ultrasound

What can be used to relax the smooth muscle portion of the esophagus?

N-butylscopolammonium bromide (Buscopan®)

What can be used to relax the striated muscle portion of the esophagus?

oxytocin

When is oxytocin contraindicated for choke in the striated muscle portion of the esophagus?

pregnant mares

A 22-year-old Thoroughbred mare is presented for bilateral green nasal discharge, retching, coughing and inappetence noted after her evening meal. The owner recently switched this mare to a pelleted diet because of her poor dentition. A slight swelling is noted in the proximal-left jugular groove just caudal to the ramus of the mandible. Based on the presumed diagnosis, what is the best initial treatment protocol?

Withhold food and water, give sedatives and oxytocin and recheck in 2 hours

2 multiple choice options

What is the initial treatment for choke?

1. Sedation and analgesia with horse in empty stall

2. Pass NG tube until resistance is felt

3. Pump water in or use a funnel and gently apply pressure to the obstruction

4. Keep the head low to prevent aspiration of food material in trachea

5. Repeat steps until cleared

What is the treatment for persistent choke that can't be cleared with initial treatment?

1. Place horse in stall

2. Nothing Per Os

3. IV fluids and electrolytes

4. Sedatives to relax esophagus

5. Obstruction often resolves with time

6. Sometimes general anaesthesia needed

What are the refeeding considerations once choke is cleared?

1. Refeeding is critical from 24-48h

2. Inflamed esophagus

3. Motility may be abnormal

4. Re-obstruction is likely

5. Dietary modifications are necessary (use easily digestible feed)

6. May need esophagotomy when diet change is not enough

How should prolonged choke >48hrs be treated?

1. Broad spectrum antibiotics

2. Anti-inflammatory therapy

3. Sucralfate

4. Refeeding considerations

What are the complications of choke?

1. Aspiration pneumonia

2. Esophageal Stricture (linear or circumferential)

3. Esophageal rupture (extra- or intrathoracic)

Which horse breed is predisposed to megaesophagus from muscular hypertrophy of the caudal esophagus?

friesians

What are the causes of megaesophagus?

1. Acquired

2. Congenital

3. Can happen after prolonged choke

What should be ruled out before diagnosing megaesophagus?

underlying myopathy

What is the treatment for megaesophagus?

1. Target underlying cause

2. Dietary modifications

What is the prognosis of congenital megaesophagus?

poor

Farusa has nasal discharge and has been retching and gagging after eating a pelleted diet. What is the best initial approach for this horse?

Sedate first

3 multiple choice options

Farusa's choke is resolved, but she is coughing and has a fever the next day. What is the most likely issue?

aspiration pneumonia

2 multiple choice options

What are the treatment options for aspiration pneumonia?

1. NSAIDs

2. Fluid therapy

3. Broad spectrum antibiotics (might need to culture)