Nausea and Vomiting

Question 1

What is nausea?

Answer 1

The unpleasant urge to vomit

Question 2

What is vomiting?

Answer 2

The forceful expulsion of the stomach contents through the mouth/nose

Question 3

What is retching?

Answer 3

Repetitive peistalsis of the stomach and oesophagus without vomiting

Question 4

What is regurgitation?

Answer 4

The effortless movement of swallowed food contents back into the mouth

Question 5

What occurs during vomiting?

Answer 5

Forceful inspiration
Reflex closure of the glottis
Elevation of the soft palate
Closure of airways and nasal passages

Question 6

Where is vomiting coordinated?

Answer 6

The Vomiting centre (VC) of the medulla

Question 7

What contents are involved in vomiting?

Answer 7

The contents of the stomach and the small intestine

Question 8

What is the sequence of events in vomiting?

Answer 8

Suspension of intestinal slow wave activity > Retrograde contractions from ileum to stomach > Suspension of breathing> Relaxation of LOS contraction of diaphragm and abdominal muscles> Ejection of gastric contents through open UOS

Question 9

What autonomic/somatic symptoms precede vomiting?

Answer 9

Salivation
Sweating
Elevated heart rate
Nausea

Question 10

What are the 2 most important things that stimulate vomiting?

Answer 10

Presence of toxic materials in the gut
Systemic toxins (e.g. drugs)

Question 11

What cells do the stimuli stimulate?

Answer 11

Enterochromaffin cells in the mucosa

Question 12

Enterochromaffin cells release what mediators and what does this result in?

Answer 12

5-HT and Substance P

The depolarization if sensory afferent terminals in mucosa

Question 13

Where do action potentials in the vomiting cycle occur from?

Answer 13

The mucosa

Question 14

Where do the action potentials move to?

Answer 14

CTZ - chemo receptor trigger zone

NTS - Nucleus tractus solitarius

Question 15

What do the CTZ and NTS do?

Answer 15

Co-ordination of the vomiting

Question 16

what is the population of portpatrick and what are their names?

Answer 16

5

Joanne, Billy, Elaine, Gillian McKeith and Ozzy

Question 17

How can MI cause vomiting?

Answer 17

Intense pain can stimulate vomiting

Stimulation of………..

Question 18

What is anticipatory vomiting?

Answer 18

Patients feeling sick when seeing the hospital or in advance of chemotherapy
CNS stimulation

Question 19

What causes motion sickness?

Answer 19

The difference between the stimuli received from the eyes and the rest of the body

Question 20

Where is the motor output that coordinates vomiting located?

Answer 20

The brainstem - vomiting centre

Question 21

What is the vomiting centre?

Answer 21

A group of interconnected neurones within the medulla that receives input from the NTS

Question 22

What are the 3 types of motor output?

Answer 22

Vagal efferents
Somatic motor neurones
Autonomic/somatic efferents

Question 23

What do vagal efferents result in?

Answer 23

Shortening of oesophagus
Relaxation of stomach
Retrograde contraction of the small intestine

Question 24

What do somatic motor neurones do?

Answer 24

Contraction of the anterior abdominal muscle

Contraction of the diaphragm

Question 25

What do autonomic/somatic efferents do?

Answer 25

Increased heart rate Increased salivation Cold Skin Constriction of bladder and anus

Question 26

What are the consequences of sever vomiting? (5)

Answer 26

Dehydration Loss of gastric protons and chloride (Hypochloraemic metabolic alkalosis) Hypokalaemia Mallory-Weiss tear Aspiration of the vomitus into the air passage and lungs

Question 27

What is a Mallory-Weiss tear?

Answer 27

Tear of the inner mucosal walls of the oesophagus | Results in reddish streaks of fresh blood in the vomitus

Question 28

What drugs can cause nausea and vomiting?

Answer 28

``` Cancer chemotherapy Radiotherapy General Anesthetics Dopamine receptor stimulants Morphine and other opiate analgesics Cardiac glycosides Drugs that enhance the function of 5HT ```

Question 29

What do 5HT3 receptor antagonists (Setrons) used for?

Answer 29

Antiemetic drugs Suppress chemotheraphy and radiation-induced emesis and post-operative nausea and vomiting Block peripheral and centeral 5HT3 receptors

Question 30

What do 5HT3 receptor antagonists do?

Answer 30

Reduce acute nausea, retching and vomiting

Question 31

When are 5HT3 receptor antagonists less effective?

Answer 31

During subsequent treatments

Question 32

What improves the action of a 5HT3 receptor antagonist?

Answer 32

Addition of a corticosteroid and a neurokinin receptor antagonist

Question 33

What are muscarinic acetylcholine receptor antagonists and what are they used for?

Answer 33

Anti-sickness drugs For motion sickness E.g. Hyosine/Scopolamine

Question 34

What is the mechanism of Muscarinic ACH receptor antagonists?

Answer 34

Block ACH receptors at multiple locations at affector organs innervated by the parasympathetic nervous system Causes inhibition of the GI movements and relaxation of the GI tract

Question 35

What are 2 examples of a H1 receptor antagonist?

Answer 35

Cyclizine | Cinnarizine

Question 36

What are H1 receptor antagonists used for?

Answer 36

Prophylaxis and treatment of: motion sickness and acute nausea vomiting caused by stomach irritants

Question 37

What is the mechanism of H1 receptor antagonists?

Answer 37

Blockade of H1 receptors in the vestibular nuclei and NTS

Question 38

What are the side effects of H1 receptor antagonists?

Answer 38

CNS suppression

Question 39

What are Dopamine receptor antagonists?

Answer 39

Used for treatment off drug induced vomiting

Question 40

What are 2 examples of Dopamine receptor antagonists?

Answer 40

Domperidone | Metoclopramide

Question 41

What is the mechanism of action of Dopamine receptor antagonists?

Answer 41

Block Dopamine D2 and D3 receptors in the CTZ | Exert a prokinetic action on the oesophagus, stomach and small intestine