Pharyngeal and oesophageal disease

Question 1

What are the 3 phases of swallowing?

Answer 1

Oral
Pharyngeal
Oesophageal

Question 2

Outline the oral phase of swallowing

Answer 2

Stimulated by oral tactile receptors
Afferent signals transmitted to the medulla
Integration in swallowing centre
Motor impulses propogated to pharynx/ oesophagus by Cranial nerves
Food is moved in a dorso-caudal direction by tongue pressing on the soft palate
Bolus arrives in the pharynx
This initiates tactile receptors that start in the pharyngeal phase

Question 3

Outline the pharyngeal phase

Answer 3

Soft palate is pulled dorsally
The palatial folds move medially preventing food from going into the nasal pharynx
Vocal cords move medially
Epiglottis covers the larynx
Upper Oesophageal sphincter relaxes to receive bolus

Question 4

Outline the oesophaeal phase

Answer 4

The cricopharyngeal muscle constricts after the bolus has passed
Waves of peristalsis occur in the oesophagus

Question 5

What are some of the more specific Hx/ PE/ MDB tests you should consider for pharyngeal/ oesophageal disease Ix?

Answer 5

Observe patient eating

Include CK on MDB

Question 6

Compare pharyngeal and oesophageal disorder eating

Answer 6

Pharyngeal - Immediate ejection of undigested food
Repeated swallow attempts
Poor ability to drink
Possible pain on swallowing
Oesophageal - Variable time after eating to eject undigested food (normally within couple of hours)
Single swallow attempt
Variable ability to drink
Possible pain on swallowing

Question 7

What are the Ddx for pharyngeal disease?

Answer 7

Physical disorders - FB, neoplasia, inflammation, trauma, TMJ issues
Functional disorders - CNS dz, CN dz, NM dz
Other - cricopharyngeal achalasia

Question 8

How can you investigate physical pharyngeal disease?

Answer 8

GA and direct exam
Endoscopy
Radiography/ CT

Question 9

How can you investigate functional pharyngeal disease?

Answer 9

Fluoroscopy
ACh receptor antibody titre for MG
Muscle/ nerve biopsy
EMG

Question 10

What is cricopharyngeal achalasia?

Answer 10

Failure of the cricopharyngeal muscle to relax in swallowing
Cockers predisposed to the congenital form, which can be treated with cricopharyngeal myotomy
Acquired may be associated with hypothyroidism or part of a polymyopathy

Question 11

Outline nasopharyngeal polyps

Answer 11

More cats than dogs
Nasal signs/ phonation changes
Can be removed by Sx or traction, but traction has a 1/3 recurrence rate
Ideally CT to assess
If the middle ear is affected, the bulla osteotomy will help

Question 12

Compare canine and feline oesophaguses

Answer 12

Feline - bottom third is made up of smooth muscle, whereas in dogs it is all skeletal.
Can see the blood vessels in cats when you can’t in dogs

Question 13

How is investigation of oesophageal disease different to pharygneal

Answer 13

With physical, can do contrast radiography
Can’t really do just a direct exam
Functional is the same

Question 14

What are the differentials for physical oesophageal disease?

Answer 14

Extramural obstruction - PRAA, mediastinal disease, thymoma
Mural - neoplasia/ abscess/ stricture, oesophagitis
Intramural - FB
Other - hiatal hernia

Question 15

What are the DDx for Functional oesophageal diseases

Answer 15

Muscle - polymyopathy, dermatomyositis, Addisons
Nerve - Polyneuropathy, dysautonomia
NMJ - MG
Other - mega oesophagus

Question 16

Outline the causes of oesophagitis

Answer 16

Causes - increased acid secretion/ regurge/ caustic substances/ v+
Can lead to strictures (65% strictures associated with GA)
Inflammation leads to decreased motility

Question 17

How do you treat oesophagitis?

Answer 17

Anti acid - the best is omeprazole
Prokinetics not great for direct treatment but may reduce reflux and allow healing (cisapride better than metoclop)
Unclear benefit of sucralfate
Low fat liquid food to enhance clearance

Question 18

How can a hiatal hernia be diagnosed?

There is an increased incidence in BOAS dogs
Normally needs surgical correction

Answer 18

Radiographs - v hard
Fluoroscopy - still may be missed as is intermittent. Increase the chance by increasing intra abdominal pressure by raising the hind legs
Sometimes endoscopy may work

Question 19

Outline oesophageal FBs

Answer 19

Terriers predisposed
Normally occur at the heart base, thoracic inlet or cardia
Leads to spasm, oedema, abrasion, ulceration, perforation

Question 20

How do you treat an oesophageal FB

Answer 20

Remove with endoscopy - use long rigid forcepts and assess after removal
Should x ray after to check for pneumomediastinum (which would need surgery)/ aspiration pneumonia

Question 21

Outline post op management of oesophageal FBs

Answer 21

Nil per os - PEG tube
Omeprazole to prevent reflux
Little evidence for sucralfate but makes sense to use

Question 22

What can cause a stricture?

Answer 22

Post FB (1-3 weeks after)
Oesophagitis (can be quick)
Doxycycline (can be quick)

Question 23

How can you treat an oesophageal stricture?

Answer 23

Conservative - liquid diet

Interventional - balloon dilation with intralesional steroid injection or bougienage (similar success rates)

Question 24

Outline investigation/ treatment of a vascular ring anomaly

Answer 24

Should occur post weaning in young animals
contrast radiographs or endoscopy
Treatment is sx
Oesophageal diverticulae will continue post op ad require ongoing management

Question 25

Outline congenital megaoesophagus

with all MO, there is decreased to absent motility leading to dilation

Answer 25

Predisposed breeds are mini schnauzers, Irish setters, great danes
Guarded prognosis but some gain function with age
N.B some young terriers have signs consistent with MO without dilation, these gain function with age.

Question 26

Which breeds are predisposed to acquired MO?

Answer 26

GSDs
Great danes
Irish setters

Question 27

What are some of the Ddx for MO?

Answer 27

CNS - neoplasia/ trauma/ brainstem lesions/ distemper
Peripheral neuropathies - lead, acrylamide, thallium/ polyneuritis/ polyradiculoneuritis/ gangioradiculitis/ dysautonomia/ bilateral vagal damage/
NMJ dz - MG/ botulism/ tetanus/ acetylcholinesterase toxicity
Myopathy - oesophagitis/ SLE/ glycogen storage disease/ polymyositis/ dermatomysositis/ cachexia/ Addisons/ hypothyroidism
Misc - pyloric stenosis/ GDV/ pituitary dwarfism/ thymoma/ idiopathic/ mediastinitis

Question 28

What is myasthenia gravis?

Answer 28

Immune mediated disease of the neuromuscular junction
ABs produced against the acetyl choline receptors
This reduces NMJ transmission
Can be focal or generalised
Predisposed breeds = Akita, GSD, retrievers, Scotties, Pointers
GSD/ Retriever predisposed to focal disease
Test with AB titre test although not 100% sensitive

Question 29

How can you treat MG?

N.B remission common in 1month to 1 year - a decreasing AB titre can suggest impending remission

Answer 29

Acetyl choline esterase inhibitors
Don’t use immunosuppressives - aspiration pneumonia common and steroids reduced muscle strength
Even in MO cases where the titre test is -ve, consider trial tx

Question 30

How can you treat MG?

N.B remission common in 1month to 1 year - a decreasing AB titre can suggest impending remission

Answer 30

Acetyl choline esterase inhibitors
Don’t use immunosuppressives - aspiration pneumonia common and steroids reduced muscle strength
Even in MO cases where the titre test is -ve, consider trial tx

Question 31

How can you treat MO?

Answer 31

High calorie food
Feed in specific posture (consider bailey chair)
Tailor make diet to the patient - trial meat balls first but may need to do liquid
If drinking is a struggle trial ice
Consider gastrotomy tube, however this does not address saliva issue and also possible poor welfare never getting to eat
Prokinetics do not help