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Vomiting: Mechanism, Causes and Consequences
Mechanism
Vomiting is the forcible expulsion of gastrointestinal contents through the esophagus and mouth. It results when receptors are stimulated which contribute impulses to the vomiting center in the brain. The vomiting center has inputs mainly from:
Causes
Gastrointestinal causes of vomiting include:
1.Obstructing disorders (bowel obstruction)
3.Impaired motor function
Consequences
Excessive or repeated vomiting can cause dehydration and may lead to severe disturbances in the electrolyte and acid-base balance in the body.
Dehydration – due to loss of water from the GI tract. Hypokalaemia – due to loss of the potassium ions in gastrointestinal secretions Hypochloremia – due to loss of chloride ions in the vomitus Alkalosis - due to loss of H+ ions in the vomitus. (Since large amount hydrochloric acid is lost in the vomitus, the blood becomes alkaline as the stomach attempts to replace its lost acid). These water and electrolyte disturbances must be considered when managing the patient.
Vomiting is the forcible expulsion of gastrointestinal contents through the esophagus and mouth. It results when receptors are stimulated which contribute impulses to the vomiting center in the brain. The vomiting center has inputs mainly from:
- Stretch or irritant receptors in the stomach (responds to excessive gastric distention or ingestion irritants or emetics)
- Chemoreceptor trigger zones in the floor of the fourth cerebral ventricle (responds to increases in ICP)
- Mechanical receptors in the throat
- Vestibular apparatus (responsible for the ‘travel/motion sickness’)
Causes
Gastrointestinal causes of vomiting include:
1.Obstructing disorders (bowel obstruction)
- Pyloric, small bowel or colonic obstruction
- Mechanical (tumor, hard feces, polyps, volvolus, complicated inguinal hernias)
- Paralytic ileus (Hirschsprung disease)
- Stricture (carcinoma, diverticular disease, Chron’s disease, ischemic colitis)
3.Impaired motor function
- Gastropareisis
- Intestinal pseudo obstruction
- Functional dyspepsia
- GERD
Consequences
Excessive or repeated vomiting can cause dehydration and may lead to severe disturbances in the electrolyte and acid-base balance in the body.
Dehydration – due to loss of water from the GI tract. Hypokalaemia – due to loss of the potassium ions in gastrointestinal secretions Hypochloremia – due to loss of chloride ions in the vomitus Alkalosis - due to loss of H+ ions in the vomitus. (Since large amount hydrochloric acid is lost in the vomitus, the blood becomes alkaline as the stomach attempts to replace its lost acid). These water and electrolyte disturbances must be considered when managing the patient.
Latest page update: made by dr.rufusrajadurai
, Nov 28 2007, 12:19 PM EST
(about this update
About This Update
Edited by dr.rufusrajadurai
2 words added
5 words deleted
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- complete history)
Edited by dr.rufusrajadurai
2 words added
5 words deleted
view changes
- complete history)
Keyword tags:
alkalosis
dehydration
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