Nausea%20-and-%20vomiting Signs and Symptoms

It is of prime importance to differentiate vomiting from other physical phenomena:

• Regurgitation: Passive phenomenon during which esophageal contents flow into the mouth
• Rumination: Passive phenomenon during which recently ingested food is regurgitated effortlessly into the mouth, whereupon it is rechewed and reswallowed or spat out

Nausea

• Described as the sensations that are felt immediately before vomiting

Vomiting

• Physical event that results in the speedy, forceful evacuation of stomach contents up to and out of the mouth
• May or may not be preceded by nausea
• Retching or repetitive active contraction of the abdominal muscles occurs between nausea and vomiting
  
  • Retching is without the discharge of gastric contents from the mouth
• Vomiting is triggered by afferent impulses to the vomiting center located in the brain medulla from the chemoreceptor trigger zone, pharynx, GI tract (through vagal afferent fibers) and the cerebral cortex

Infectious Causes of Nausea and Vomiting

• Several infections, most of which have systemic and GI tract involvement, may cause nausea and vomiting

Viral Infections

• Viral gastroenteritis which may be caused by rotaviruses, adenoviruses, noroviruses and other agents

Bacterial Infections

• Bacterial infections may result in the production of toxins which may act on the vomiting center in the brainstem
• Causative toxin-producing organisms include Salmonella sp, Staphylococcus aureus, Clostridium perfringens and Bacillus cereus
• Systemic infections may also give rise to nausea and vomiting, eg meningitis and hepatitis

Other Causes of Nausea and Vomiting

• Migraine
• Vertigo
• Advanced cancer
• Prolonged starvation
• Congestive heart failure
  
  • Nausea and vomiting results from passive congestion of the liver and gut
• Acute myocardial infarction (MI)
• Hypercalcemia
• Raised ICP
• Cannabinoid hyperemesis syndrome 
• Chronic nausea and vomiting syndrome
  • Combination of chronic idiopathic nausea and functional vomiting 
• Cyclic vomiting syndrome
  
  • Intermittent acute nausea and vomiting episodes of <1 week duration with asymptomatic periods in between
  • Associated with migraine headaches, motion sickness, stress and atopy
  • More common in children and young adults