N+V Flashcards
What are the different possible causes of N+V?
GI:
Gastro-enteritis
peptic ulcers
appendicitis
carcinoma
infection
ORGANIC DISEASE:
Renal failure- high urea can cause N+V
DKA
Myocardial infarction
CNS:
Migraine
Meningitis
Meniere’s
Post-op N+V
Motion sickness
DRUGS
Opiated
Antibiotics
Digoxin
Levodopa
Chemotherapy
Aminophylline/Theophylline
What is motion sickness and what groups is it most common in?
This is when there is conflicting information between the eye and body which makes us feel sick.
- Children <1 rarely get motion sickness as the labrynth isn’t yet functional
- But children aged 3-12 are the most vulnerable.
What are the 2 methods by which drugs can cause drug-induced N+V?
- They mimic the action of NTs that cause N+V e.g. opiates and levodopa do. Or they cause a change in the levels of NTs e..g. the SSRIs
- Activation of the abdominal afferent system which causes delayed gastric emptying and direct activation of mucosal afferent system.
What is mostly always given alongside an opioid?
an anti-emetic
What is Meniere’s disease?
A disorder of the inner ear- dilation of the endolinth system and excess fluid in the labrynth canals.
- most common between 20-50 years old
- can cause tinnitus, healing lord, vertigo, N+V
- Has a sudden onset in attacks that last 20 mins to several hours
What is vertigo?
- Rotation and spinning- either yourself or the environment
- 2-3 x more common in women
- if in younger often due to a viral infection, labrynthitis
- Benign paroxysmal positional vertigo (BPPV) - In the elderly, movement of calcium crystals and debris in the ear get dislodges and enter the inner ear canal and cause loss of balance
- can also be caused by MS, head injury, migraines
- also dome drugs are vestibular toxic- cause vertigo e.g. ahminoglycosides (gentamicin, anti-convulsants, furosemide- sense max rate, NSAIDs, quinine)
What causes morning sickness?
Often due to high levels of hcg- human chorionic gonadotrophin. Rapid rising of this hormone causes N+V.
What is hyperemesis gravidarum?
Severe, persistant N+V in pregnancy. Patient are often unable to keep food or drink down and can lead to dehydration, weight loss, acidosis, ketoacidosis, can be fatal.
Why do we need to treat N+V?
- Is unpleasant for patient
- Dehydration risk
- Risk of renal impatient
- Electrolyte imbalances e.g. K+, Na+, Mg2+
- weight loss
What symptoms of N+V would require referral?
- Projectile vomiting
- Sour smelling vomit
- Blood in vomit
- Duration of symptoms- dehydration risk
- first 2 can be a result of pyloric stenosis- narrowing of vent from stomach = blockage.
if with other symptoms e.g.
- Severe, long duration diarrhoea- could be infection or gastroenteritis
- weight loss
- abdo pain- appendicitis, biliary colic
- dizziness- meningitis, head injury, meniere’s disease
What are the possible targets for N+V treatment?
- H1 receptor antagonists (anti-histamines) e.g. promethazine, cinnarazine.
- Anti-muscarincs (anti-cholinergic) e.g. Hyoscine- act on M1 receptors
- D2 receptor antagonists e.g. prochlorperazine
- Anti-psychotics- also inhibit D2 receptors e.g. Halloperidol, levomepromazine
What are the possible side effects of anti-histamines?
Drowsiness, dizziness, tinitus
What anti-emetic class tends to be more effective in motion sickness?
The anti-muscarinics
What are the possible side effects of anti-muscarinics?
drowsiness, dry mouth, decreased gut motility
- increased intra-ocular pressure and HR
Where are anti-muscarinics contra-indicated?
glaucoma
Urinary retention
