Vomiting (emesis)

Vomiting or emesis (‘throwing up’) is the involuntary and forceful expulsion of the contents of the stomach through the mouth and sometimes the nose.

Nausea is the feeling that one is about to vomit. It frequently precedes but does not always lead to vomiting.

Regurgitation is the return of undigested food back up the oesophagus to the mouth, without the force associated with vomiting and is due to different causes.

Pathophysiology of vomiting:
The area postrema is a circumventricular organ on the floor of the fourth ventricle of the brain that has a chemoreceptor trigger zone. Stimulation of this can lead to vomiting.

The process or act of vomiting starts with increased saliva secretion which occurs to protect tooth enamel from stomach acids; the body then takes a deep breath to avoid aspirating vomit; the diaphragm is contracted downwards to create a negative pressure in the thorax, which will facilitate the opening of the oesophagus and distal oesophageal sphincter; retroperistalsis begins from the small intestine and sweeps up the digestive tract contents into the stomach, through the relaxed pyloric sphincter; the intrathoracic pressure lowers due to inspiration against a closed glottis. There is then an increase in abdominal pressure as the abdominal muscles vigorously contract which propels stomach contents into the oesophagus as the lower oesophageal sphincter relaxes. A sympathetic response also causes increases in sweating and heart rate.

Vomiting is often associated with retching which is similar as it involves forceful stomach contractions; however it does not bring up any content from the stomach.

Causes of vomiting:
Gastrointestinal:

Neurological:

Metabolic:

Pregnancy:

Drug reactions:

Behavioral:

Deliberate & Miscellaneuos:

  • Emetics; eating disorders; postoperative nausea and vomiting; ionizing radiation; overexertion; COVID-19; ‘functional nausea and vomiting’ (no clear cause)

Management:
Treatment of the underlying cause.
Many find ginger helpful.
Isolation if infective cause.
Maintain fluid levels; eat bland foods; avoid triggering foods.
Antiemetics

Page last updated: @ 3:48 am

 
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