Vomiting/Regurgitation Flashcards
Oesophageal Stricture
- A stricture occurs due to healing of a very inflamed area of the oesophagus; the contracture that usually helps wounds heal can have a negative effect if the inflammation was present around the entire circumference of the oesophagus.
- The scar tissue that develops following healing is not distensible like the normal oesophageal wall and therefore an obstruction is created.
- can lead to regurgitation
- An oesophageal stricture would be a rare diagnosis however it is possible that it could have occurred following general anaesthesia for his castration
- Acid gastric contents can reflux into the oesophagus when the dog is under anaesthesia and this can cause severe inflammation (oesophagitis) in some dogs
- Oesophagitis can be seen quite frequently following long general anaesthetics but it is normally mild and self limiting, possibly causing a couple of minor episodes of regurgitation in the first 48 hours post-operatively
- Remember that oesophagitis causes oesophageal dysfunction. If regurgitation is observed post-operatively it is wise to administer some gastroprotective agents, such as H2 blockers (e.g. cimetidine) or a proton pump inhibitor (e.g. omeprazole).
Megaoesophagus
(more common in dogs)
- Can be congenital
- Megaesophagus is not a single disease. Instead it is considered a combination disorder in which the esophagus (the tube that carries food and liquid between the mouth and stomach) dilates and loses motility (its ability to move food into the stomach).
- like a deflated balloon
- want to use imaging to always rule out in a case of regurgitation though!
- When esophageal motility is decreased or absent, food and liquid accumulate in the esophagus
- run risk of aspiration pneumonia
- Poor prognosis: nothing can be done to promote motility of the oesophagus
- Can treat and also do postural feeding!- requires a lot of dedication
esophageal diverticulum in dogs
Vascular Ring Anomaly
- often congenital
- This is a developmental anomaly of the great vessels which results in encircling of the oesophagus and trachea by a complete or incomplete ring of vessels.
- This condition is seen most commonly in German Shepherd dogs, Irish Setters, Persian and Siamese cats (generally < 6 months old).
- A number of different anomalies can occur. The most common is a persistent right aortic arch.
- Surgery to release the oesophagus from the encircling ring is the optimum treatment to provide the best chance for a good long term outcome
- This is achieved by performing an intercostal thoracotomy to reach the site of constriction at the base of the heart
Possible Causes of Regurgitation
- Oesophageal disease
- Structural/Obstruction
- Foreign body
- Stricture
- Neoplasia
- Vascular ring anomaly (This is a congenital problem and is very unlikely at Mog’s age)
- Functional
- Secondary to oesophagitis
- Megaoesophagus – congenital/acquired
Oesophageal Foreign Bodies
- Most commonly seen in dogs of terrier breeds, but can affect any breed
- Less common in cats
- Bones, hide chews, balls, toys, fish hooks, needles, string
- Large foreign bodies:
- Thoracic inlet
- Heart base
- Caudal oesophagus
- Acute: regurgitation, retching, gagging, hypersalivation, restlessness, inappetence
- Chronic: weight loss, regurgitation, inappetance
- Perforation of the oesophagus: pyrexia, depression, dyspnoea
- Aspiration pneumonia: dyspnoea (labored breathing)
- First attempt endoscopy retrieval and then possibly surgery to remove
- or if in the caudal oesophagus, can push organic material into the stomach
Oesophagotomy
The operation of making an incision into the esophagus, for the purpose of removing any foreign substance that obstructs the passage
- Foreign bodies which cannot be retrieved via endoscopy or cannot be pushed into the stomach
- Fish hooks esp. those with barbs
- Permits lavage of the tissues surrounding a perforated oesophagus
- Permits repair of oesophageal tears
Oesophagus Anatomy
- The oesophageal wall had 3 layers
- Mucosea, submucosa, muscularis
- Tethered at both ends
- Pharynx → Diaphragm
- Segmental blood supply
- Individual arteries supply sections of the oesophagus with few anastomosing branches
- Veins drain into the jugular and azygous veins
- Lymphatics drain into thoracic and abdominal lymph nodes
Poor Oesophageal Healing
- Lack of a serosa
- A segmental blood supply
- Constant motion of swallowing and breathing
- Lack of an omentum
- Tension at the surgical site
Hiatal Hernia
- A hiatal hernia is the abnormal movement of part of the stomach from its normal position in the abdomen into the chest.
- During the development of a puppy, these openings may be excessively large, allowing organs which should remain in the abdomen to pass into the chest.
- The stomach can become permanently displaced but more commonly slides back and forth between the abdomen and the chest.
- This lesion would produce an abnormal appearance at the caudal thorax and the diaphragmatic hiatus, not at the heart base
Persistent Right Aortic Arch
- Normal anatomy: The aorta develops from the left aortic arch. The ligamentum arteriosum passing from the pulmonary artery to the aorta is short and does not cross the midline.
- Persistent right aortic arch: The right arch remains in place to become the aorta. If the ligamentum arises from the left pulmonary artery the ligamentum crosses the midline and forms a ring encircling the midline structures of the trachea and oesophagus.
Treatment: Vascular Ring Anomalies
- To prepare animal for surgery while this treatment is arranged
- Slurry diet
- Feed from a height
- Maintain upright for 20 mins post feeding
- Treatment for aspiration pneumonia if required:
-Antibiotics, oxygen, nebulise, coupage
Surgery:
- Division of the vascular ring
- Ligamentum arteriosum
- Transection of perioesophageal fibrous bands
- Dilation of oesophagus
Oropharyngeal Stick Injury
- Oropharyngeal penetrating stick injury is a traumatic injury to the oropharynx caused by impact with a stick.
- This injury occurs due to chasing behaviour.
- The dog runs fast with the neck extended meaning that if an injury occurs the stick can penetrate a long way into the neck and even the thorax.
- This can cause injury to important structures in the neck and can introduce infection
- The cervical tissue planes are continuous with the structures in the cranial mediastinum. A site of bacterial infection in the neck can track into the chest (septic mediastinitis) potentially causing life threatening sepsis
- In many dogs that do not have appropriate investigation and surgical exploration if appropriate, recurrent abscesses and draining sinuses develop, due to bacterial infection and/or foreign material in the cervical tissues
Ranula
- A ranula is a mucus extravasation cyst involving a sublingual gland and is a type of mucocele (A mucous cyst) found on the floor of the mouth
- Ranulas present as a swelling of connective tissue consisting of collected mucin from a ruptured salivary gland caused by local trauma
- treatment: removal surgically of the salivary gland chain
- In some dogs with a sublingual salivary mucocoele the mucocoele forms under the tongue, rather than dependently, and in this case it is called a ranula
Sialoadenectomy
- surgical excision of a salivary gland
- ex: A skin incision is made over the mandibular salivary gland. The mandibular salivary gland must be removed with the sublingual salivary glands because they form a chain and often share a duct system
- The sublingual salivary gland chain is traced all the way rostral to the oral cavity and is ligated and divided.
Esophageal Diverticulum
- An esophageal diverticulum is an outpouching of mucosa through the muscular layer of the esophagus.
- It can be asymptomatic or cause dysphagia and regurgitation.
- Diagnosis is made by barium swallow; surgical repair is rarely required
Dyspnoea
- difficult or laboured breathing
Regurgitation
Causes - Oesophageal Disorders
(Anatomical)
- hiatal hernia
- diverticulum
- vascular ring anomaly (GSD, IS, Persians & siamese)
Causes - Oesophageal Disorders
(Megaoesophagus)
- congenital
- acquired –> loss of tone
- air filled
- guarded prognosis
- postural feeding
Causes - Oesophageal Disorders
(External Compression)
- Persistent R. aortic arch
- Mediastinal lymphoma
- Thyroid tumours
Causes - Oesophageal Disorders
(Internal Obstruction)
- physical or functional: Foreign bodies, Strictures
Causes - Oesophageal Disorders
(Oesophagitis)
- Trauma
- Reflux or gastric acid
- Irritation
Causes - Oesophageal Disorders
(Intramural lesions)
- Neoplasms
- Abscesses
- Granulomas
Treatment for Regurgitation
Vomiting
(Physiology)
- vomiting is also known as emesis
- Chemoreceptor Trigger Zone (CTZ) has receptors for Dopamine and 5-HT (which is essentially serotonin) –> actually, we know that chemotherapy can trigger this CTZ
- The CTZ is conveniently located outside of the BBB where as the vomiting center is not - even though they are both located on the medulla oblongata
- Once the CTZ is stimualted by chemoreceptors then it will stimualte the muscarinic receptors of the vomiting center - once these receptors are stimulated, they will cause the vomiting reflex
Stages of Vomiting and Treatment
Vomiting v. Regurgitation
Vomiting: Primary GI disease
Location of Lesion
- Stomach to Anus
Vomiting: Primary GI disease
(Causes and Investigating Primary GI Disease)
Vomiting: Secondary (Metabolic) GI Disease
Location of the Lesion and Types of lesion
Vomiting: Secondary (Metabolic) GI Disease
(Investigation and Common Causes)
5 Internal/External Triggers for Vomiting Reflex
There are essentially 5 main internal and external triggers that will cause the vomiting reflex to be stimulated:
- Gastric Irritation, Cytotoxic Drugs - Visceral receptors - vagus nerve
- Pharyngeal Stimulation (gag reflex) - Glossopharyngeal nerve
- Motion/vertigo, middle ear disease
- Drugs (e.g. opiates -ex: morphine and chemo), Uraemia (renal failure), radiation sickness **See this stimuli more often in our veterinary patients
- Pain, sights, anticipation, smells
Metclopramide
- antiemectic
- when we discuss peripheral receptors in the gastrointestinal tract, we know that metclopramide will act on these, but this antiemectic will also act upon the CRTZ
Maropitant
(Tradename- Cerenia)
NK1 antagonists
Nk1 antagonists - maropitant (Cerenia) –> multi-effective, useful against:
- peripheral gastrointestinal receptors that may stimulate vomiting
- also going to have an affect on the CRTZ
- at higher doses can be useful for the vestibular system (ear)
- vomiting center directly
Phenothiazines
(Acepromazine)
- Phenothiazines (Acepromazine) : useful for the
- CRTZ
- Vomiting Centre
- Vestibular Center as well
Vomiting v Regrgitation Clues
Why is it Important to Define the Problem between Vomiting and Regurgitation
Clinical Approach to Vomiting
Symptomatic Approach to the Vomiting Patient
When is Symptomatic Therapy not enough?
When is Symptomatic Therapy not appropriate?
Patient vomiting… need to investigate.. Define the system
Define the system
(primary GI)
Define the System
(Secondary GI)
Define the System
(Secondary GI)
Endogenous Toxins
Historical Information to help distinguish
Vomiting in Primary GI
Behavior in Animal with Primary GI
When should Primary GI be strongly suspected?
When should secondary GI be strongly suggested?
Behavior with Secondary GI
What if you cant tell primary or secondary from signs/behavior?
Investigate Primary GI
Define the location of lesions in Primary GI disease
How to Investigate primary GI disease
(endoscopy)
How to Investigate Primary GI Disease
(Exploratory laporoscopy)
First protocol in investigating Secondary GI Disease?
To Investigate Secondary GI Disease
(Endogenous Toxins)
To Investigate Secondary GI Disease
(Radiography/US)
To Investigate Secondary GI Disease
(Exploratory laparotomy)
Primary GI
(Define the Location)
Key Differentials for Diseases of the Stomach
(Primary GI)
5
Key Differentials for Diseases of the Intestine
(Primary GI)
4
“Common” Primary GI causes of vomiting
Define the Location - Secondary GI
Define the Location - Secondary GI
(D,D, I, I, N, N, T, T)
“Common” Secondary GI causes of Vomiting
*Important*
6
To Investigate Regurgitation
Define the Lesion - Oesophageal Disorders
(Oesophagitis, Intramural Lesions)
Diagnostic Investigation of Regurgitation
Diagnostic Approach to the “Vomiting” Patient
(Summary)
Goals of Investigating Secondary GI
Goals of Investigating Primary GI
Once you can rule out Secondary GI Disease
