PATHOLOGY - Oesophageal Disease Flashcards
What are the three phases of swallowing?
Oral phase
Pharyngeal phase
Oesophageal phase
Describe the oral phase of swallowing
The oral phase of swallowing involves the prehension of food, mastication and the tongues caudal movement of the bolus towards the pharynx
Describe the pharyngeal phase of swallowing
During the pharyngeal phase of swallowing, the bolus stimulates pressure sensitive sensory receptors at the palatoglossal arches which stimulate the rostral movement of the hyoid apparatus to hold the epiglottis over the larynx, as well as the coordinated contraction of the pharyngeal muscles to push the bolus towards the oesophagus and relaxation of the upper oesophageal sphincter
Describe the oesophageal phase of swallowing
During the oesophageal phase of swallowing, oesophageal periastalsis moves the bolus towards the cardiac sphincter
Describe the anatomical topography of the oesophagus
The oesophagus begins at the pharynx and runs on the left side of the body, dorsal to the trachea in the mediastinum and enters the abdomen through the oesophageal hiatus at the diaphragm and into the cardia of the stomach
Which muscles make up the upper oesophageal sphincter?
Cricopharyngeal muscle
Thyropharyngeal muscle
Which structure makes up the lower oesophageal sphincter?
Cardia of the stomach
What is dysphagia?
Dysphagia is difficulty swallowing
What is the difference between mechanical and physical dysphagia?
Mechanical dysphagia refers to physical obstructions or structural abnormalities whereas functional dysphagia refers to abnormal functionality of the normal swallowing apparatus
What are the three classifications of dysphagia?
Oral dysphagia
Pharyngeal dysphagia
Oesophageal dysphagia
What are the clinical signs of oral dysphagia?
Abnormal prehension of food
Dropping food
Halitosis
Hypersalivation
Coughing
What are some of the possible causes of mechanical oral dysphagia?
Periodontal disease
Oral foreign body
Oral mass
Cleft palate
Temporomandibular joint (TMJ) disease
Trauma
What are some of the possible causes of functional oral dysphagia?
CN V, VII and XII dysfunction
Myopathy
Glossitis
What are the clinical signs of pharyngeal dysphagia?
Hard, repetitive swallowing whilst eating or drinking (hallmark clinical signs)
Halitosis
Hypersalivation
Coughing
Gagging
What are some of the possible causes of mechanical pharyngeal dysphagia?
Pharyngeal foreign body
Pharyngeal mass
Nasopharyngeal polyp
Tonsilitis
Retropharyngeal lymphadenopathy
Trauma
What are some of the possible causes of functional pharyngeal dysphagia?
CN IX, X and XI dysfunction
Cricopharyngeal achalasia
Cricopharyngeal asynchrony
Myasthenia gravis
Hypothyroidism
Hypoadrenocorticism
Hypocalcaemia
What is cricopharyngeal achalasia?
Cricopharyngeal achalasia is where the upper oesophageal sphincter fails to relax during swallowing
What is cricopharyngeal asynchrony?
Cricopharyngeal asynchrony is where the contraction of the pharyngeal muscles and relaxtion of the upper oesophageal sphincter is not coordinated during swallowing
How can cricopharyngeal achalasia and asynchrony be treated?
Surgical correction
Botox (relaxes the upper oesophageal sphincter)
Why is botox not ideal for long term treatment of cricopharyngeal achalasia and asynchrony?
Botox is not ideal for long term treatment of cricopharyngeal achalasia and asynchrony as it only lasts up to 3 - 4 months before having to be redone
How do you approach investigating oesophageal dysphagia/disease?
- Assess history, signalement and clinical signs
- Clinical examination
- Diagnostic tests and diagnostic imaging
- Treatment plan
What are the possible clinical signs of oesophageal dysphagia?
Regurgitation (hallmark clinical sign)
Clinical signs of aspiration pneumonia
Halitosis
Hypersalivation
Coughing
Gagging
Odynophagia
Ravenous appetite or decreased appetite
Weight loss
What is the difference between regurgitation and vomiting?
Regurgitation is the passive evacuation of food and/or fluid from the oesophagus due to oesophageal disease, whereas vomiting is the forceful evacuation of the stomach and/or duodenal contents
What is the main complication associated with regurgitation and vomiting?
Aspiration pneumonia
What are the clinical signs of aspiration pnuemonia?
Soft cough
Pyrexia
Dyspnoea
Tachypnoea
Lung crackles on auscultation
How do you diagnose aspiration pneumonia?
Radiography
Note the right middle lung lobe is most likely to be affected by aspiration pneumonia
How do you treat aspiration pneumonia?
Oxygen supplementation
Sedation
Broad spectrum antibiotics
Coupage
Fluid therapy if indicated
What is coupage?
Coupage is a form of thoracic physiotherapy that can be beneficial in loosening and removinf excess secretions from the lungs
What is odynophagia and how does it often present in small animals?
Odynophagia is painful swallowing and often presents as neck stretching in small animals
Which clinical pathological tests can be useful to do when investigating oesophageal dysphagia/disease?
Haematology/biochemistry
Acetylcholine receptor antibodies assay
T4/TSH test
ACTH stimulation test
Serum lead levels
Neurological examination
You don’t have to do all of these tests, it would depend on the history and signalement
What are the typical haematology results in a patient with oesophageal dysphagia/disease?
Haematology results are usually completely normal but may have an inflammatory leukogram if the patient has aspiration pneumonia
What are the typical biochemistry results in a patient with oesophageal dysphagia/disease?
Biochemistry results are usually normal in patients with oesophageal dysphagia/disease
How does lead poisoning cause oesophageal dysphagia?
Lead poisoning can cause severe oesophageal dilatation
Which diagnostic imaging techniques are used to investigate oesophageal dysphagia/disease?
Radiography
Contrast radiography (used less commonly nowadays)
Fluoroscopy
Endoscopy
Why is it important to try and do conscious radiographs when imaging the oesophagus?
It is important to do conscious radiographs when imaging the oesophagus as sedation can cause gas accumulation in oesophagus, making it challenging to decifer if the gas is due to megaoesophagus or secondary to the sedation
Which contrast medium should you use for contrast radiography of the oesophagus?
Barium sulphate however you should use a water based contrast if a perforation is suspected
What are the benefits of fluoroscopy for imaging the oesophagus?
Fluoroscopy allows for the assessment of oesophageal motility
What should clients be informed about before their pet undergoes fluoroscopy?
Clients should be informed that there is a risk of patients aspirating during fluoroscopy
What are the benefits of endoscopy for imaging the oesophagus?
Endoscopy allows for assessment of the oesophageal lumen and mucosa as well as allows for biospy and cytology sampling
Remember you will have to anaesthetise your patient for endoscopy
(T/F) Oesophageal surgery is often indicated and relatively easy to do
FALSE. Oesophageal surgery is rarely indicated and high risk to do
What are the risks of oesophageal surgery?
Increased risk of aspiration on induction of anaesthesia
Risk of contaminating the thoracic cavity
Post-operative healing is challenging
What is an oesophagotomy?
An oesophagotomy is an incision into the oesophageal lumen
What is an oesophagectomy?
An oesophegectomy is the removal of a portion of the oesophagus
What is an oesophagostomy?
An oesophagstomy is the creation of an opening in the oesophagus for a feeding tube
What are some of the possible causes of mechanical oesophageal dysphagia?
Vascular ring anomalies
Foreign bodies
Oesophageal strictures
Hiatal hernia
Oesophageal neoplasia
Parasitic granuloma
What is a vascular ring anomaly?
A vascular ring anomaly is a congenital defect where a normal blood vessel is in the wrong place
What is the most common vascular ring anomaly and how does it affect the oesophagus?
A persistent right aortic arch is the most common vascular ring anomaly and it is where the aorta develops from the right aortic arch rather than the left, resulting in abnormal positioning of the ligamentum arteriosum, resulting in significant narrowing or obstruction of the oesophagus
Which dog breeds are predisposed to a persistent right aortic arch?
German Shepherd
Irish Setter
What are the key clinical signs of a persistent right aortic arch?
Regurgitation
Weight loss
Failure to thrive
± Clinical signs of aspiration pneumonia
When do the clinical signs of a persistent right aortic arch typically arise?
The clinical signs of a persistent right aortic arch typically arise at weaning when the patient is converted from liquid to solid food. Liquid food can typically pass through the oesophageal narrowing however solid food cannot
How do you treat a persistent right aortic arch?
Surgery to transect the ligamentum arteriosum
What should you be aware of after treating a persistent right aortic arch?
After transecting the ligamentum arteriosum, the patient may continue to have regurgitation due to the motility problems resulting from the chronic over distension of the oesophagus
What are some of the common sites for oesophageal foreign body obstruction?
The oesophagus narrows at the level of the thoracic inlet, cardia of the stomach and just cranial to the diaphragm, making these common sites for oesophageal foreign body obstruction
What are the clinical signs of an oesophageal foreign body obstruction?
Regurgitation
Halitosis
Hypersalivation
Gagging
Odynophagia
± Clinical signs of aspiration pneumonia
Remember these clinical signs of oesophageal dysphagia will present acutely
What are the potential consequences of an oesophageal foreign body?
Oesophagitis
Pressure necrosis
Perforation
Fistula (usually between oesophagus and thoracic cavity)
Diverticulum
How do you diagnose an oesophageal foreign body obstruction?
Radiography
How do you treat an oesopahgeal foreign body?
Stabilise the patient followed by endoscopic removal of the foreign body either orally or push the foreign body into the stomach where it can be removed using a gastrotomy. Remember to use the endoscope to assess the oesophageal mucosa for any complications of the foreign body and treat appropriately
Remember you will have to anaesthetise your patient for endoscopy
What is the prognosis for endoscopic removal of a oesophageal foreign body?
Excellent prognosis
What should you do if you are unable to endoscopically remove an oesophageal foreign body (i.e. if there is a large perforation)?
If you are unable to remove an oesophageal foreign body endoscopically, you will have to consider an oesophagotomy or an oesophagectomy
This has a much more guarded prognosis
What is an oesophageal stricture?
An oesophageal stircture is the progressive development of a ring of fibrous tissue secondary to oesophagitis. This ring of fibrous tissue causes narrowing of the oesophagus
What are the clinical signs of an oesophageal stricture?
Regurgitation
Ravenous appetite
Weight loss
Tends to tolerate swallowing liquids better than solids
± Clinical signs of aspiration pneumonia
|These clinical signs of oesophageal dysphagia will be progressive
How do you diagnose oesophageal strictures?
Contrast radiography
Fluoroscopy
Endoscopy
How do you treat oesophageal strictures?
Endoscopic balloon dilation followed by treatment for the primary oesophagitis
What can be administered to prevent the recurrence of oesophageal strictures?
Steroids
What are the two classifications of hiatal hernias?
Sliding hitatal hernia
Perioesophageal hiatal hernia
What is a sliding hiatal hernia?
A sliding hiatal hernia is where the distal oesophageal and a portion of the stomach herniates through the oesophageal hitaus
What is a perioesophageal hiatal hernia?
A perioesophegeal hiatal hernia is where a portion of the stomach herniates through a defect adjacent to the oesophageal hitaus
What are the main consequences of a hiatal hernia?
A hiatal hernia decreases the lower oesophegeal sphincter tone allowing for gastroesophageal reflux which can cause oesophagitis
(T/F) Hiatal hernias can be congenital or acquired
TRUE.
Which dog breeds are predisposed to hiatal hernias?
Shar Pei
Brachycephalics
Why are brachycephalic breeds predisposed to hiatal hernias?
Brachycephalic breeds often have brachycephalic airway obstruction syndrome (BOAS) which causes an increased respiratory effort which generates negative pressure which can cause hiatal hernias
What are the clinical signs of a hiatal hernia?
Regurgitation
Vomiting
Haematemesis
Hypersalivation
Weight loss
± Clinical signs of aspiration pneumonia
When do the clinical signs of a congenital hiatal hernia typically arise?
The clinical signs of a congenital hiatal hernia typically arise at weaning when the patient is converted from liquid to solid food
How do you diagnose a hiatal hernia?
Contrast radiography
Fluoroscopy
Endoscopy
How do you treat a small hiatal hernia?
Low fat diet
Prokinetic drugs
Treat any oesophagitis
How do low fat diets and prokinetics help when treating hiatal hernias?
Low fat diets are preferable as high fat diets can delay gastric emptying which increases the pressure on the stomach due to the accumulation of gastric contents. Prokinetic drugs increase gastrointestinal motility which increases gastric emptying and reduces the pressure on the stomach - which can worsen the hiatal hernia
Give an example of a prokinetic drug
Metoclopramide
How do you treat a large hiatal hernia?
Surgery is required to treat a large hiatal hernia
What should be done before treating hiatal hernias in patients with brachycephalic airway obstruction syndrome (BOAS)?
For patients with brachycephalic airway obstruction syndrome (BOAS), you should surgically treat the BOAS before treating the hiatal hernia to reduce the risk of recurrence
What is the prognosis for hiatal hernias?
Good prognosis
(T/F) Oesophageal neoplasia is very common
FALSE. Oesophageal neoplasia is very rare
Which primary neoplasms can be found in the canine oesopagus?
Fibrosarcoma
Osteosarcoma
Leiomyosarcoma
Leiomyoma
Which primary neoplasms can be found in the feline oesopagus?
Squamous cell carcinoma
What is perioesophageal neoplasia?
Perioesophageal neoplasia is where neoplasms develop adjacent to the oesophagus i.e. the thymus and the heart base, and can cause compression of the oesophagus resulting in signs of oesophageal dysphagia
What are the clinical signs of oesophageal neoplasia?
Progressive clinical signs of oesophageal dysphagia and obstruction
Odynophagia
Weight loss
±Clinical signs of aspiration pneumonia
These clinical signs will be progressive
How do you diagnose oesophageal neoplasia?
Radiography
CT
Endoscopy followed by a biospy
What is the prognosis for oesophageal prognosis?
Poor prognosis
What are parasitic granulomas?
Note parasitis granulomas are very rare in the UK
Parasitic granulomas develop within the oesopahgus due to the Spiroceca lupi nematode which is acquired via the ingestion of dung beetles
How do you diagnose spircoceca lupi?
Identify spiroceca lupi eggs on a faecal flotation test
Which anthelmintic do you use to treat spiroceca lupi?
Doramectin
What can parasitic granulomas develop into?
Parasitic granulomas can develop into osteosarcomas within the oesophagus
What are some of the possible causes of functional oesophageal dysphagia?
Megaoesophagus
Oesophageal dysmobility
Oesophagitis
Gastroesophageal reflux
Myasthenia gravis
What is a megaoesophagus?
A megaoesophagus is the acute dilatation and aperistalsis of the oesophagus
Aperistalsis is the absence of peristalsis
(T/F) Megaoesophagus can be congenital or acquired
TRUE.
When do the clinical signs of congenital megaoesophagus typically arise?
The clinical signs of congenital megaoesophagus typically arise at weaning when the patient is converted from liquid to solid food
Which dogs breeds are predisposed to megaoesophagus?
German Shepherds
Irish Setters
Newfoundlands
Labradors
What are some of the causes of acquired of megaoesophagus?
Idiopathic
Myasthenia gravis (most common)
Severe oesophagitis
Myopathy
Neuropathy
Toxins
Hypothyroidism
Hypoadrenocorticism
What are the clinical signs of megaoesophagus?
Regurgitation
Weight loss
± Hypersalivation
± Clinical signs of aspiration pneumonia
± Clinical signs of underlying disease
How do you diagnose megaoesophagus?
Radiography
Endoscopy
Investigation of underlying disease processes
When would endoscopy be the most appropriate method to diagnose megaoesophagus?
Endoscopy would be most appropriate to diagnose megaoesophagus suspected to be secondary to severe oesophagitis
Which tests can be useful to investigate underlying causes of megaoesophagus?
Haematology/biochemistry
Acetylcholine receptor antibody assay
Endoscopy to investigate oesophagitis
CK/AST levels (myopathies)
Neurological examination
TSH/T4 tests
ACTH stimulation test
How do you treat megaoesophagus?
Postural feeding
Sildenafil
Treat underlying disease if secondary megaoesophagus
What can you recommend to owners to help with postural feeding?
‘Baby style’ chairs can be contructed to help with postural feeding
What is sildenafil?
Sildenafil is a drug which relaxes the lower oesophageal sphincter to reduce resistance, allowing boluses to move from the oesophagus into the stomach more easily
Which prokinetic drug has been shown to not help in the treatment of megaoesophagus?
Meloclopramide
What is oesophageal dysmotility?
Oesophageal dysmotility is where there is impaired oesophageal motility however there is no oesophageal dilatation
(T/F) Oesophageal dysmobility can be congenital or acquired
TRUE.
Which dog breeds are predisposed to oesophageal dysmotility?
Terriers are predisposed to oesophageal dysmotility however the motility tends to improve with age
What are some of the causes of acquired oesophageal motility?
The causes of acquired oesophageal motility are the same as megaoesophagus
What are the clinical signs of oesophageal dysmotility?
The clinical signs of oesophageal dysmotility are the same as megaoesophagus
How do you diagnose oesophageal dysmotility?
Fluoroscopy
Investigate causes of underlying disease
Fluoroscopy is essential for diagnosis
How do you treat oesophageal dysmotility?
Postural feeding
Sildenafil
Treat underlying disease if secondary megaoesophagus
What is oesophagitis?
Oesophagitis is oesophageal inflammation
What are some of the underlying causes of oesophagitis?
Chronic vomiting
Ingestion of caustic agents
Foreign bodies
Gastroesophageal reflux
What are the potential clinical signs of oesophagitis?
Asymmptomatic
Regurgitation
Hypersalivation
Odynophagia
Decreased appetite
Weight loss
± Clinical signs of aspiration pneumonia
Clinical signs of oesophagitis are very variable
How do you diagnose oesophagitis?
Endoscopy
Investigate underlying cause
How do you treat oesophagitis?
Small, low fat, high protein meals
Liquid sucralfate
Metocloprimide (prokinetic)
Omeprazole
Treat underlying cause
Why do you use metoclopramide in the treatment of oesophagitis?
Metocloprimide increases gastrointestinal motility which increases gastric emptying and reduces stomach contents and gastroesophageal reflux which can cause and worsen oesophagitis
Why do you use omeprazole in the treatment of oesophagitis?
Omeprazole is a proton pump inhibitor which inhibits gastric acid secretion to help reduce gastroesophageal reflux whihc can cause and worsen oesophagitis
What is gastroesophageal reflux?
Gastroesophageal reflux is the movement of gastric acid and ingesta from the stomach back into the oesophagus due to disorders of the lower oesophageal sphincter
What is the main consequence of gastroesophageal reflux?
Gastroesophageal reflux can cause oesophagitis
What are some of the underlying causes of gastroesophageal reflux?
Chronic vomiting
Hiatal hernia
Gastric emptying disorder
Upper airway obstruction
General anaesthesia
How can an upper airway obstruction cause gastroesophageal reflux?
An upper airway obstruction can generate negative pressure which can decrease the lower oesophageal sphincter tone and lead to gastroesophageal reflux
How can general anaesthesia cause gastroesophageal reflux?
Anaesthesia can relaxtion of the lower oesophageal sphincter resulting in gastroesophageal reflux
How do you diagnose gastroesophageal reflux?
Gastroesophageal reflux is very challenging to diagnose and you often have to assume based on clinical signs or other disease processes present
How do you treat gastroesophageal reflux?
Low fat diet
Liquid sucralfate
Metocloprimide (prokinetic)
Omeprazole
Treat underlying cause
What is the difference between congenital and acquired myasthenia gravis?
Congenital myasthenia gravis is an inherited disorder of the acetylcholine receptors at the neuromuscular junction resulting in muscle weakness, whereas acquired myasthenia gravis is an autoimmune disorder where antibodies are produced against the acetylcholine receptors at the neuromuscular junction resulting in muscle weakness
How do you diagnose acquired myasthenia gravis?
Acetylcholine receptor antibody assay
How do you treat myasthenia gravis?
Pyridostigmine
What is the mechanism of action of pyridostigmine?
Pyridostigmine inhibits acetylcholinesterase which would usually break down acetylcholine at the neuromuscular junction. Pyridostigmine increases the amount of time the acetylcholine is present within the neuromuscular junction, enhancing the transmission of nerve impulses
What is the prognosis for myasthenia gravis?
Only 50% of myasthenia gravis cases will improve with treatment
