Nausea and vomiting

• Nausea


  Symptom of feeling near to the point of vomiting
• Vomiting


  Process by which stomach contents are expelled through the mouth
• Retching


  Effort of vomiting but nothing is expelled
• Epidemiology of nausea and vomiting


  • Common, especially in childhood
  • Any age group can be affected
  • Are symptoms of other conditions therefore epidemiology determined by the condition
• Most common causes of nausea and vomiting

  • Gastroenteritis: Norovirus 50%, Rotavirus 20% (children), Adenovirus, Astrovirus
• Chemoreceptor trigger zone (CTZ)


  In brain, toxic substances may stimulate its chemoreceptors
• Vomiting centre


  In brainstem, receives nerve signals from CTZ and other pathways e.g. gut, liver signals, sends impulses to pharynx, larynx, gut etc. to cause nausea and vomiting plus other symptoms
• Causes of nausea and vomiting

  • Gastrointestinal (food poisoning, acute appendicitis, GORD, blockage, overindulgence)
  • Metabolic (diabetic ketoacidosis, hyperCa2+)
  • Neurological (head injury, meningitis, migraine i.e. Pain, stress)
  • Ear disorder (labyrinthitis, infection)
  • Drug and chemical (chemotherapy)
  • Postoperative (general anaesthetic)
  • Psychiatric (bulimia nervosa)
  • Pregnancy
  • Movement (motion/mountain sickness)
• Nausea and vomiting in pregnancy

  • Usually begins between week 4-7
  • Peaks between week 9-16
  • Usually resolves week 16-20
  • 'Morning sickness' = misnomer (a wrong or inaccurate use of a name or term)
  • Hyperemesis gravidarum
• Causes of nausea and vomiting in pregnancy

  • hCG - placental origin
  • Oestrogen - increased levels
  • Evolution - prevent person eating potentially harmful foods
  • Gastric dysfunction - increased progesterone level causes smooth muscle relaxation which impairs small bowel motility (therefore delays gastric emptying)
  • Multifactorial
  • More common in multiple pregnancy, history of nausea
• Motion sickness


  • Caused by repeated movements
  • Going over bumps in car
  • Moving up and down in a boat, plane, train or rides
  • Going in circles
  • Inner ear sends different signals to your brain from those your eyes are seeing
  • Confusing messages cause nausea
  • All people can be affected by intense motion
  • More common in children and women
  • Usually throughout journey but can continue post-motion ('mal de debarquement')
• Symptoms of nausea and vomiting

  • Sweating and cold sweats
  • Increased saliva production
  • Headaches
  • Feeling cold
  • Going pale (pallor)
  • Feeling weak
• Management/treatment of vomiting


  • Not much once started
  • Stay hydrated - rehydration therapy may be indicated
  • Treatment depends on causality
  • Sometimes be harmful if cause not known
• Antiemetics for nausea and vomiting

  • Prochlorperazine (dopamine antagonist, phenothiazine)
  • Buccal tab for nausea and vomiting associated with migraine only for prescription medication
  • Can be prescribed otherwise
• Antiemetics for motion sickness

  • Hyoscine (antimuscarinic with central and peripheral action, several forms and brands e.g. Joy-Rides®, Kwells®, patches - prescription only)
  • Sedating antihistamines: cinnarizine (Stugeron®), promethazine (Phenergan®), cyclizine (slightly less effective than hyoscine, better tolerated)
• Practical measures for nausea

  • Fresh air
  • Distractions e.g. music, TV
  • Regular sips of cold drink
  • Ginger or peppermint tea
  • Ginger foods
  • Smaller, more frequent meals
  • Avoid strong smells
• What not to do for nausea

  • Eat or cook strong-smelling foods
  • Eat hot, fried, greasy foods
  • Eat too quickly
  • Have a large drink with meals
  • Lie down soon after eating
  • Wear tight clothes around waist or tummy
• Strategies for motion sickness prevention


  • Sit in front of car/middle of boat
  • Not reading or watching film
  • Look at fixed point ahead on horizon
  • Close eyes/sleep
  • Focus on your breathing (slow)
  • Fresh air (open window)
  • Avoid heavy meals or alcohol
  • Break up long journeys to get fresh air/drink water/take a walk
• Strategies for nausea and vomiting in pregnancy

  • Rest
  • Drink and eat little but frequently
  • Eat plain biscuits/crackers in morning
  • Bland, small, protein-rich meals low in carbohydrates and fat
  • Avoid caffeine, alcohol or foods/smells which trigger nausea
  • Ginger
  • Acupressure e.g. Sea-Bands®
• First-line prescribed treatment for nausea and vomiting in pregnancy

  • Cyclizine or promethazine (antihistamines)
  • Xonvea® (doxylamine/pyridoxine)