Clincal CNS Nausea/GA

Question 1

Name the GI causes of vomiting:

Answer 1

Gastro-enteritis
Appendicitis
Peptic ulceration
Gastric carcinoma
Infection (common)

Question 2

Name organic diseases that cause vomiting:

Answer 2

Renal failure (uraemia)- high levels of this toxin
Diabetic ketoacidosis
Myocardial infarction- occur on inferior wall more likely

Question 3

Name CNS causes that can cause vomiting:

Answer 3

Migraine
Meningitis
Vestibular disease (Meniere’s)

Question 4

Name post-op causes that can cause vomiting:

Answer 4

Complex and multifactorial e.g pain, surgery, anaesthesia

Question 5

What causes motion sickness?

Answer 5

Conflicting info between eyes and body

Question 5

What are the common ages for motion sickness?

Answer 5

Children less than 1- labyrinth not functional so rarely occurs
Children 3-12 most vunerable

Question 6

Name common drugs that cause N&V:

Answer 6

Opiates
Antibiotics (doxy)
Digoxin
Levodopa
Aminophylline/theophylline
Chemo

Question 7

Which methods are N&V caused by?

Answer 7

1 of 2 methods:
Mimicking the action of NT/ changing levels of NT
Activating the abdominal afferent system (peripheral)

Question 8

Name different type of drugs that mimic/ change NT:

Answer 8

Mimicking action of NT:
Opioids, Ldopa
Changing levels:
5HT3 re-uptake inhibitors (for depression)

Question 9

Describe how activating the abdominal afferent system can cause N&V:

Answer 9

Delaying gastric emptying
Direct activation of mucosal afferent system

Question 10

What is Ménière’s disease?

Answer 10

Disorder of the inner ear
Excess fluid on labyrinth canals (hydros)

Question 11

What is the epidemiology of Ménière’s disease?

Answer 11

0.1% of population, common between 20-50 years old

Question 12

What are the symptoms of Ménière’s disease?

Answer 12

Incapacitating attacks characterised by:
-giddiness, vertigo, N&V
-hearing loss
-functional paralysis
-tinnitus
Sudden onset, lasts 20mins to several hours
Migraine present in 30%

Question 13

What is vertigo?

Answer 13

Sensation of rotation or spinning
Patient (objective) or their surrounding (subjective)

Question 14

What are the common causes of vertigo in different age groups?

Answer 14

Young people- labyrinthitis
Elderly- BPPV

Question 15

What is BPPV?

Answer 15

Benign Paroxysmal Positional Vertigo
Movement of naturally occurring calcium salts

Question 16

What are other causes of vertigo?

Answer 16

Head injury
Migraine
MS
Excess alcohol

Question 17

When should a patient be referred if they have vertigo?

Answer 17

If they have N&V associated

Question 18

Name some vestibular toxic drugs:

Answer 18

Aminoglycosides e.g gentamicin
Anticonvulsants
Furosemide- max rate 4mg/min- ototoxicity
NSAIDs
Quinine

Question 19

When does morning sickness occur?

Answer 19

50-90% if women experience nausea during first trimester
Begins shortly after first missed period
Peaks weeks 10-14
Often disappears after 4th month

Question 20

What is morning sickness due to?

Answer 20

High levels of HCG- human chorionic gonadotropin

Question 21

Name a severe form of morning sickness:

Answer 21

Hyperemesis Gravidarum

Question 22

Describe hyperemesis gravidarum:

Answer 22

Severe persistent N&V during pregnancy- can’t keep anything down
Weight loss, dehydration, acidosis, ketosis
1-3 per 1000 deliveries
Untreated can be fatal to mother/foetus/both

Question 23

What are the reasons for treating N&V?

Answer 23

Highly unpleasant for patient
Dehydration
Weight loss
Renal impairment
Electrolyte abnormalities

Question 24

Describe the severity of symptoms of N&V that would require referral:

Answer 24

Projectile vomiting- pyloric stenosis Sour smelling vomiting- pyloric stenosis Blood in vomit

Question 25

Describe other symptoms of N&V that would require referral:

Answer 25

Severe diarrhoea/ long duration -gastro-enteritis, infection Weight loss Abdominal pain -appendicitis, biliary colic, renal colic, hernias Dizziness -meningitis, head injury, Meniere's disease

Question 26

Describe the onset of action of H1 receptor antagonists:

Answer 26

Act within 2 hours Theoclate salts longer acting than hydrochloride

Question 27

Name the MOA of promethazine:

Answer 27

H1 receptor antagonist Also some D2

Question 28

Name the SEs of H1 receptor antagonists:

Answer 28

Drowsiness, dizziness, tinnitus Antimuscarinic, antidopaminergic (promethazine) SEs

Question 29

What are the CI for promethazine:

Answer 29

Glaucoma and other muscarinic/ dopaminergic

Question 30

How do antimuscarinics work?

Answer 30

Act on muscarinic (M1 receptors centrally) Antispasmodic gut action

Question 31

What are the SEs of anticholinergics?

Answer 31

Drowsiness, dry mouth, dry skin, decreased gut motility Increased IOP and HR

Question 32

What are the CI of anticholinergics aka muscarinics?

Answer 32

Glaucoma and urinary retention

Question 33

How does prochlorperazine work?

Answer 33

Inhibits D2r and also some M1 (muscarininc)

Question 34

Name SEs of prochlorperazine:

Answer 34

Anti-dopaminergic- extrapyramidal e.g dystonia, dyskinesia, Parkinsonism- all more than chlorpromazine Anti-cholinergic- drowsiness, blurred vision, dry mouth

Question 35

How does chlorpromazine work?

Answer 35

D2r antagonist, H1, antimuscarininc

Question 36

What are the counselling points for chlorpromazine?

Answer 36

More sedative effects than prochlorperazine Used in palliative care Contact senitisation- carer don't touch them

Question 37

How does metoclopramide work?

Answer 37

Blocks D2R and some 5HT3 Antimuscarininc Peripherally and centrally Antiemetic and prokinetic properties (stim gastric emptying)- not in physicsal gut obstruction

Question 38

What is the dosing of metoclopramide and why?

Answer 38

Max 30mg/day for 5 days (10mg QDS) Lowest dose for shortest time Neurological adverse effects- acute dystolic reactions, movement disorders

Question 39

What are the SEs of metoclopramide?

Answer 39

10% experience transient SEs; drowsiness dizziness, anxiety Extrapyrmidal SEs e.g dystonia, tardive dyskinesia, oculogyric crisis) more common in 12-19 yrs and females

Question 40

What are the interactions with metoclopramide?

Answer 40

Cyp2D6 inhibitor Fluoxetine, paroxetine Causes increase in metoclopramide

Question 41

What is the dosing of domperidone and why?

Answer 41

Lowest dose for shortest time- max 1 week due to CV risk

Question 42

What are the CI of domperidone?

Answer 42

Cardiac disease (irregular HR, QT) or any meds that cause QT prolongation e.g methadone, citalopram, amiodarone Not in children and those less than 35kg

Question 43

How does domperidone work?

Answer 43

D2R antagonist- outside BBB Prokinetic Antimuscarininc (periphery)

Question 44

What are the interactions of domperidone?

Answer 44

CYP3A4 inhibitors e.g macrolides, azoles Leads to higher doses of domperidone

Question 45

How do 5HT3 antagonists work?

Answer 45

5HT3r located peripherally on vagal nerve endings and vomiting centre- endochromaffin

Question 46

What are CIs of ondansetron?

Answer 46

QT prolongation drugs or abnormality as can increase risk of ventricular arythmias- congenital long QT syndrome

Question 47

What are the common SEs of ondansetron?

Answer 47

Constipation, feeling hot, headache, hypotension QT prolongation

Question 48

What are the interactions with ondansetron?

Answer 48

Many CYP enzymes such as inducers which increases clearance of ondansetron

Question 49

What are non pharmacological treatments for nausea and vomiting?

Answer 49

Acupressure Transcutaneous Electrical Nerve Stimulation (TENS)

Question 50

What are the first line treatments for morning sickness?

Answer 50

Promethazine Prochloperazine Cyclizine Doxylamine and pyridoxine Chlorpromazine

Question 51

What are the second line treatments for morning sickness?

Answer 51

Domperidone Ondansetron- avoid in first 12 weeks due to orofacial cleafing Metoclopramide

Question 52

Describe doxylamine and pyridoxine:

Answer 52

Doxylamine- H1 r antagonist Pyridoxine- VitB6 Anticholingeric Only medicine licensed in N&V in pregnancy

Question 53

Name different antiemetics used for CINV:

Answer 53

Dexamethasone 5HT3 r antagonists for acute and delayed NK1 antagonists- delayed but can be acute

Question 54

What are the SEs of dexamethasone?

Answer 54

If BD dosing insomnia SEs at night Limited SEs as short amount of time used and low doses

Question 55

What are the SEs/ interactions with NK1 antagonists?

Answer 55

Diarrhoea, fatigue, nausea Metabolised by CYP3A4