Vomiting Flashcards
What is vomiting?
- the expulsion of gastric contents and sometimes proximal duodenal contents back into the oral cavity
What is the advantage to vomiting?
- protecting the individual from ingestion of noxious substances
What disorders can vomiting result from?
- GI
- other abdominal conditions
- systemic or metabolic disease
- drug toxicity
Vomiting can have serious consequences what are these?
- volume depletion
- acid-base and electrolyte disturbances
- oesophagitis
- aspiration pneumonia
- malnutrition
What 3 components can vomiting be divided into?
- nausea
- retching
- vomiting
What is nausea?
- precedes retching and vomiting
What are outward signs of nausea?
- depression
-shivering - hiding
- yawning
- lip smacking
- licking
There is often increased salivation and swallowing before vomiting - why is this?
- serves to lubricate the oesophagus and neutralise gastric acid
What causes the reflex of duodenal contents into the stomach?
- reduction in gastric acid and oesophageal motility but increase in proximal small intestine motility
How does retching occur?
- forceful contractions of the abdominal muscles and diaphragm
- this occurs with a closed glottis which produces a negative intrathoracic pressure and positive abdominal pressure
- very forceful expulsion of gastric contents out of the mouth
What do the pressure changes result in during retching?
- result in passage of gastric contents into a dilated oesophagus
What happens when cats retch?
- herniation of the abdominal oesophagus and gastric cardia into the thoracic cavity
Vomiting doesn’t originate from contractions of the gastric muscle - What are the steps involved in the vomiting process?
- deep inspiration and simultaneous closure of the glottis and nasal cavities
- forceful contraction of the abdominal muscles
- large increased pressure in the abdominal cavity which is transferred to contents of the stomach
- cardiac sphincter opens and gastric contents expelled into the oesophagus
- upper oesophageal sphincter opens
- contents expelled through the mouth
Ingesta in the oesophagus doesn’t necessarily result in vomiting - What happens if the upper sphincter remains closed?
- secondary oesophageal peristalsis is triggered by dilation of the oesophagus and the contents is returned to the stomach
What happens of there is high pressure in the stomach?
- the upper sphincter is also opened and vomiting occurs
What is vomiting regulated by?
What is the location of the regulator?
- vomiting is regulated by the vomiting centre
- found within the medulla oblongata of the brain
What can stimulate the vomit centre?
- stimulation is either via humoral pathway initiated by blood borne substances or neural pathways leading to the vomit centre
What receptors are important in vomiting?
- receptors located throughout the abdominal viscera
- especially those found in the duodenum which contain the highest concentration
Diseases or irritation of what can stimulate vomit - and by what neurons?
- disease or irritation of the GIT
- other abdominal organs
- peritoneum
= directly stimulate the vomit though vagal afferents
Receptors in the kidneys, uterus and bladder send signals to the vomit centre how?
- send afferent signals via sympathetic nerves
Receptors in the pharynx and tonsillar foassae transmit impulses through what?
- glossopharyngeal afferents
How is the vomit centre indirectly stimulated?
- stimulated indirectly via humoral pathways via stimulation of the chemoreceptor trigger zone
Where is the chemoreceptor trigger zone located?
- located in the floor of the 4th ventricle
- lies on the blood side of the blood brain barrier and therefore can be reached by most blood borne substances
The chemoreceptor trigger zone con trains receptors - what do they do?
- detect emetic agents in the blood and the CSF and relays info to the vomiting centre
What are other sites besides the chemoreceptor tigger zone relay information to the vomiting centre to induce emesis?
- GI tract
- the vestibular system
- higher centres in the cortex and thalamus
What is Apomorphine?
- is a non-ergoline dopamine agonist with high binding affinity to dopamine D2, D3 and D5 receptors
- stimulation of D2 receptors in the caudate-putamen, a region of the brain responsible for locomotor control, may be responsible for apomorphines action
What are the metabolic/endocrine causes of vomiting?
- uraemia
- hyoadrenocorticism
- diabetes mellitus
- hyperthyroidism
- hepatic disease
- endotoxemia/septicaemia
- hepatic encephalopathy
- enterocyte disorders
- acid-base disorders
What gastric disorders can cause vomiting?
- gastritis’s
- helicobacter
- parasites
- ulceration
- neoplasia
- foreign bodies
- dilation-volvulus
- hiatal hernia
- obstruction
- motility disorders
What intoxicants can cause vomiting?
- lead
- ethylene glycol
- zinc
- strychnine
What small intestine disorders can cause vomiting?
- inflammatory bowel
- neoplasia
- foreign body
- intussusception
- parasites
- parvovirus
- SIBO
What drugs can cause vomiting?
- cardiac glycosides
- erythromycin
- chemotherapy agents
- apomorphine
- xylazine
- NSAID/s
What LI disorders cause vomiting?
- colitis
- obstipation
- parasites
What dietary issue cause vomiting?
- indiscretion
- intolerance
- allergy
What abdominal disorders cause vomiting?
- pancreatitis
- peritonitis
- neoplasia
- hepatobiliary disease
How can vomiting be treated?
- depends on the cause
What is regurgitation?
- passive retrograde passage of food and/or fluid from the oesophagus into the oral cavity and/or nasal cavities
What is regurgitation usually indicative of?
- usually indicative of oesophageal dysfunction du to mechanical obstructive disease or functional abnormalities
What is mechanical obstructive disease?
- persistent right aortic arch
What can acquired myasthenia gravis lead to?
- lead to mega oesophagus
What are the clinical signs of regurgitation?
- indigested or digested food that may or may not be tubular in shape
- may occur shortly after eating it may be delayed for hours after eating
- weight loss
- increased hunger
- dyspnoea
- fever
- cough
How can you diagnose regurgitation?
- radiographs
- endoscopy
- CBC/ biochemistry/electrolytes
How can regurgitation be treated?
- elimination of underlying cause
- appropriate antibiotics for aspiration pneumonia
- small meals little and often
- feed from a height
What means its vomiting not regurgitation?
- forceful ejection of stomach contents
- accompanied by retching
- requires effort
-usually receded by salivation - animal often uneasy
- not specific to the stomach
Regurgitation?
- backflow of undigested food
- just open mouth
- very passive
- no warning
- usually specific to the oesophagus (obstruction or motility disorder)
