Vomiting

Question 1

What is vomiting?

Answer 1

• the expulsion of gastric contents and sometimes proximal duodenal contents back into the oral cavity

Question 2

What is the advantage to vomiting?

Answer 2

• protecting the individual from ingestion of noxious substances

Question 3

What disorders can vomiting result from?

Answer 3

• GI
• other abdominal conditions
• systemic or metabolic disease
• drug toxicity

Question 4

Vomiting can have serious consequences what are these?

Answer 4

• volume depletion
• acid-base and electrolyte disturbances
• oesophagitis
• aspiration pneumonia
• malnutrition

Question 5

What 3 components can vomiting be divided into?

Answer 5

• nausea
• retching
• vomiting

Question 6

What is nausea?

Answer 6

• precedes retching and vomiting

Question 7

What are outward signs of nausea?

Answer 7

• depression
  -shivering
• hiding
• yawning
• lip smacking
• licking

Question 8

There is often increased salivation and swallowing before vomiting - why is this?

Answer 8

• serves to lubricate the oesophagus and neutralise gastric acid

Question 9

What causes the reflex of duodenal contents into the stomach?

Answer 9

• reduction in gastric acid and oesophageal motility but increase in proximal small intestine motility

Question 10

How does retching occur?

Answer 10

• 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

Question 11

What do the pressure changes result in during retching?

Answer 11

• result in passage of gastric contents into a dilated oesophagus

Question 12

What happens when cats retch?

Answer 12

• herniation of the abdominal oesophagus and gastric cardia into the thoracic cavity

Question 13

Vomiting doesn’t originate from contractions of the gastric muscle - What are the steps involved in the vomiting process?

Answer 13

1. deep inspiration and simultaneous closure of the glottis and nasal cavities
2. forceful contraction of the abdominal muscles
3. large increased pressure in the abdominal cavity which is transferred to contents of the stomach
4. cardiac sphincter opens and gastric contents expelled into the oesophagus
5. upper oesophageal sphincter opens
6. contents expelled through the mouth

Question 14

Ingesta in the oesophagus doesn’t necessarily result in vomiting - What happens if the upper sphincter remains closed?

Answer 14

• secondary oesophageal peristalsis is triggered by dilation of the oesophagus and the contents is returned to the stomach

Question 15

What happens of there is high pressure in the stomach?

Answer 15

• the upper sphincter is also opened and vomiting occurs

Question 16

What is vomiting regulated by?
What is the location of the regulator?

Answer 16

• vomiting is regulated by the vomiting centre
• found within the medulla oblongata of the brain

Question 17

What can stimulate the vomit centre?

Answer 17

• stimulation is either via humoral pathway initiated by blood borne substances or neural pathways leading to the vomit centre

Question 18

What receptors are important in vomiting?

Answer 18

• receptors located throughout the abdominal viscera
• especially those found in the duodenum which contain the highest concentration

Question 19

Diseases or irritation of what can stimulate vomit - and by what neurons?

Answer 19

• disease or irritation of the GIT
• other abdominal organs
• peritoneum
  = directly stimulate the vomit though vagal afferents

Question 20

Receptors in the kidneys, uterus and bladder send signals to the vomit centre how?

Answer 20

• send afferent signals via sympathetic nerves

Question 21

Receptors in the pharynx and tonsillar foassae transmit impulses through what?

Answer 21

• glossopharyngeal afferents

Question 22

How is the vomit centre indirectly stimulated?

Answer 22

• stimulated indirectly via humoral pathways via stimulation of the chemoreceptor trigger zone

Question 23

Where is the chemoreceptor trigger zone located?

Answer 23

• 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

Question 24

The chemoreceptor trigger zone con trains receptors - what do they do?

Answer 24

• detect emetic agents in the blood and the CSF and relays info to the vomiting centre

Question 25

What are other sites besides the chemoreceptor tigger zone relay information to the vomiting centre to induce emesis?

Answer 25

- GI tract - the vestibular system - higher centres in the cortex and thalamus

Question 26

What is Apomorphine?

Answer 26

- 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

Question 27

What are the metabolic/endocrine causes of vomiting?

Answer 27

- uraemia - hyoadrenocorticism - diabetes mellitus - hyperthyroidism - hepatic disease - endotoxemia/septicaemia - hepatic encephalopathy - enterocyte disorders - acid-base disorders

Question 28

What gastric disorders can cause vomiting?

Answer 28

- gastritis's - helicobacter - parasites - ulceration - neoplasia - foreign bodies - dilation-volvulus - hiatal hernia - obstruction - motility disorders

Question 29

What intoxicants can cause vomiting?

Answer 29

- lead - ethylene glycol - zinc - strychnine

Question 30

What small intestine disorders can cause vomiting?

Answer 30

- inflammatory bowel - neoplasia - foreign body - intussusception - parasites - parvovirus - SIBO

Question 31

What drugs can cause vomiting?

Answer 31

- cardiac glycosides - erythromycin - chemotherapy agents - apomorphine - xylazine - NSAID/s

Question 32

What LI disorders cause vomiting?

Answer 32

- colitis - obstipation - parasites

Question 33

What dietary issue cause vomiting?

Answer 33

- indiscretion - intolerance - allergy

Question 34

What abdominal disorders cause vomiting?

Answer 34

- pancreatitis - peritonitis - neoplasia - hepatobiliary disease

Question 35

How can vomiting be treated?

Answer 35

- depends on the cause

Question 36

What is regurgitation?

Answer 36

- passive retrograde passage of food and/or fluid from the oesophagus into the oral cavity and/or nasal cavities

Question 37

What is regurgitation usually indicative of?

Answer 37

- usually indicative of oesophageal dysfunction du to mechanical obstructive disease or functional abnormalities

Question 38

What is mechanical obstructive disease?

Answer 38

- persistent right aortic arch

Question 39

What can acquired myasthenia gravis lead to?

Answer 39

- lead to mega oesophagus

Question 40

What are the clinical signs of regurgitation?

Answer 40

- 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

Question 41

How can you diagnose regurgitation?

Answer 41

- radiographs - endoscopy - CBC/ biochemistry/electrolytes

Question 42

How can regurgitation be treated?

Answer 42

- elimination of underlying cause - appropriate antibiotics for aspiration pneumonia - small meals little and often - feed from a height

Question 43

What means its vomiting not regurgitation?

Answer 43

- forceful ejection of stomach contents - accompanied by retching - requires effort -usually receded by salivation - animal often uneasy - not specific to the stomach

Question 44

Regurgitation?

Answer 44

- backflow of undigested food - just open mouth - very passive - no warning - usually specific to the oesophagus (obstruction or motility disorder)