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