Nausea and Vomitting Flashcards
(51 cards)
1
Q
What is vomiting
A
Vomiting is forceful expulsion of gastric contents from the mouth
2
Q
What muscles contract to cause vomitting
A
- abdominal muscles
- diaphragm
3
Q
what muscles relax to cause vomitting
A
- stomach- - gastric lining
- relaxing of the lower oesophageal sphincter and upper oesophageal sphincter
4
Q
what can cause vomitting
A
gastric retropulsion
5
Q
what is another word for vomiting
A
emesis
6
Q
What is retching
A
- this is spasmodic rhythmic contractions of respiratory muscles that gives the feeling of wanting to vomit without expulsion of gastric contents
- generates pressure gradient that leads to vomitting
7
Q
what muscles is retching caused by
A
including diaphragm
chest wall
abdominal wall muscles
8
Q
what is nausea
A
- unpleasant sensation at the back of your throat
- awareness of urge to vomit
9
Q
what is nausea accompanied by often
A
cold sweat
pallor
salivation
disinterest in surroundings
loss of gastric tone
duodenal contractions
reflux of intestinal contents into stomach
10
Q
nausea can sometimes be…
A
relived by vomit
11
Q
what happens in nausea doesn’t go away
A
- dehydration and anorexia- this is because it makes you not want to eat
- ribs are broken
- refusal of medication - life prolonging - as medications can make you vomit
12
Q
What is cyclic vomiting syndrome
A
- rapid projectile vomit
- lasts few hours to several days followed by asymptomatic periods
- 9.6 and 14.4 episodes/ year in paediatrics & adults
- can incapacitate
- nausea is the more relevant symptom
13
Q
what is not relieved by vomitting in cyclic vomiting syndrome
A
nausea
14
Q
describe signs of gastroparesis
A
Early satiety after eating Postprandial fullness Nausea Vomiting Belching Bloating
15
Q
list some causes of nausea and vomitting
A
- chemo-radiotherapy
- infections
- severe pain
- metabolic diseases
- migraine
- pregnancy
- intracranial disease
- labyrinthine/vestibular disorder
16
Q
what is the basic pathway of vomititng
A
- The nucleus tracts solitaires relieves sensory inputs
- this causes different brainstem nuclei to coordinate vomiting
17
Q
describe hes ensory inputs to intikte vomiting
A
- the chemoreceptor trigger zone is present in the area postrema, this gets all the sensory inputs that circulate in the blood so for example come from the liver, it also gets sensory inputs from the vagus nerve
- the area postrema projects into the NTS which can project into other brainstem nuclei and cause vomitting
- the vagus receives input from all the organs and projects this into the NTS
18
Q
what brainstem nuclei causes the coordination of vomiting
A
- several structures within the reticular formation of the hindbrain
- NTS
- area postrema
- Dorsal motor nucleus of the vagus
- reticular formation
- ventrolateral medulla
19
Q
what does the NTS receive inputs from
A
Inputs from abdominal/ thoracic vagus, pharyngeal, glossopharyngeal & trigeminal nerves, spinal tract, area postrema, hypothalamus, cerebellum & vestibular/ labyrinthine systems, cerebral cortex
20
Q
what is the role of the NTS
A
Role in integrating, modulating, regulating many autonomic reflexes involved in vomiting
21
Q
Name some old drugs that were used for nausea and vomtting
A
Muscarinic (M) receptor antagonists
Histamine H1 receptor antagonists
Dopamine D2 receptor antagonists
22
Q
name some examples of dopamine D2 antagonist
A
Phenothiazines
Metoclopramide
Domperidone
23
Q
what were muscarinic M receptors antagonist used fro
A
- prevent motion sickness
- blocks acetylcholine in the brainstem and/or vestibular nuclei
e. g. Scopolamine (hyoscine)
24
Q
name an example of muscarinic M receptor antagonist
A
Hyoscine (scopolamine)
25
name some examples of histamine H1 receptors
diphenhydramine
dramamine - given to make them less drowsy
cyclizine
26
describe how cyclizine is used
Histamine H1 receptor antagonist
- pKi 8.4 (human receptor)1
Ability to inhibit pre-ganglionic cholinergic and vagal nerve activity
27
what is cyclizine recommended for by NICE
- Nausea
- vomiting
- vertigo
- motion sickness
- labyrinthine disorders
28
what were the side effects of
- muscarcinoc antagotnis
- D2 antagonists
- H2 antagonist
- muscarcinoc antagotnis = dry mouth
- D2 antagonists = extrapyramidal reactions
- H2 antagonist = drowsiness
29
name some extrapyramidal side effects
- pseudoparkinsonism
- tardive dyskinésie
- akathisia
- actue dystonia
30
describe the characteristics of the extrapyramidal side effects
pseudoparkinsonism
- stooped posture
- shuffling gait
- rigidity
- bradykinesia
- tremors at rest
tardive dyskinésie
- protrusion and rowing of the tongue
- chewing motion
- facial dyskinesia
- involuntary movements of the body and extremities
akathisia
- restless
- trouble standing still
- paces the floor
- feet in constant motion rocking back and forth
actue dystonia
- facial grimacing
- involuntary upward eye movement
- muscular spams of the tongue, face, neck and back
- layrgensl spams
31
what D2 antagonist is free of extrapyramidal side effects but what side effect does it cause
does not cross blood-brain barrier; free of extrapyramidal side effects
ventricular arrhythmia, especially at higher doses or with other drugs acting as CYP 3A4 inhibitors
32
what does metoclopramide do
- Dopamine D2 antagonist
| - stimulates gastric emptying - 5-HT4 receptor agonist - at high doses
33
what is metoclopramide used as
Widespread use as an anti-emetic*
post-operative care
gastritis, migraine, dysmenorrhoea
drug- or treatment-induced emesis including anaesthesia, radiation and/ or chemotherapy for cancer
Widespread use as a stimulant of upper gut motility
gastro-esophageal reflux disease
gastroparesis
functional dyspepsia
34
describe the patterns of vomitting that were seen with cisplatin treatment
- vomtting a lot just after treatment and then it would gradually slow down
- then you would get anticipatory vomitting
35
name some cannabinoid receptor agonists
nabilone
| levoantradol
36
what are cannabinoid receptor agonist used to treat
May treat mild/ moderate emesis
Poorly effective vs severe emesis (cisplatin)
Appetite promoting
37
what do anti cancer drugs do that causes vomiting
ANTI-CANCER CHEMOTHERAPEUTIC DRUGS LIBERATE 5-HT FROM ENTEROCHROMAFFIN CELLS LINING THE UPPER GI TRACT
- this causes vomitting
38
what do 5-HT3 receptor antagonist do
Prevent chemotherapy-induced emesis, acting mostly at GI vagal nerve endings
39
describe the anti-emetic activity of corticosteroids such as dexamethasone
Anti-inflammatory
Enhances anti-emetic efficacy of several other anti-emetics
Anti-emetic when give alone (eg.chemotherapy, post-operative nausea & vomiting)
Anti-nausea effects
May increase appetite
40
what is given for moderately sever forms of emesis
5-HT3 receptor antagonist + dexamethasone given in combination
41
what does 5-HT3 receptor antagonist + dexamethasone given in combination do
Substantial reduction in number & duration of hospital admissions + other costs associated with prevention/ management of nausea & vomiting
Reduced medical costs
Rare for patients to refuse chemotherapy because they can not tolerate the nausea or vomiting, or visiting the emergency room because of CINV-induced dehydration
42
name some examples of 5-HT3 receptor antagonist + dexamethasone
```
Granisetron
Ondansetron
Tropisetron
Dolasetron
Palonosetron: Long-Acting
Ramosetron (Japan)
High-dose Metoclopramide
```
43
what do NK1 receptors do
- blocks the action of substance P ( this is a neurotransmitter used y the vagus and some brainstem nerves)
44
what is given for sever forms of emesis
5-HT3 receptor antagonist + NK1 receptor antagonist + dexamethasone given in combination
45
why are large dose opiates sometimes unavoidable
- for pain
| - these are a prophylactic of anti-emetic medication
46
what should e used to treat opiates
Choose an anti-emetic that also enhances analgesic efficacy
| eg. Dexamethasone
47
if you have bowel obstructor what would you use
Metoclopramide (D2 antagonist, 5-HT4 agonist),
prucalopride (5-HT4 agonist)
- these stimulate gastrointestinal propulsion
48
if there is pain retropulsion and emesis caused y distention motor activity secretion in bowel obstruction what would you use
Reduce inflammation
- Dexamethasone
Reduce build-up of fluid in the lumen
- Octreotide, a somatostatin antagonist, which may also reduce pain
- Nasogastric tube, venting, gastrostomy tube
49
what is olanzapine
```
Atypical antipsychotic
(thiobenzodiazepine class)
```
May be used in breakthrough vomiting
Antagonises at D1, D2, D3, D4, 5-HT2A, 5-HT2C, 5-HT3, 5-HT6, α1 adrenergic, H1 and m1, m2, m3, m4 receptors
Some improvement in nausea when given with 5-HT3 and NK1 receptor antagonists and dexamethasone
50
what are interceptive brain regions and how are they linked to vomitting
process stress, fear
there is sustained activation in subjects reporting “severe nausea & strong stomach awareness”
51
How does diabetes lead to vomitting and nausea
- diabetic keotacidis may somehow turn on D2 receptors
- diabetic gastroparesis - stimulates the vagus nerve, might also end up with destruction of 5HT pacemaker cells in the stomach and this creates an abnormal movement in the stomach
