vomiting / emesis

see also:

• anti-emetics

• vomiting is a highly non-specific symptom
  • vomiting with significant abdominal pain suggests an abdominal cause rather than a vestibular or neurologic cause
    • if there is also a PH of abdominal surgery or a hernia then a small bowel obstruction should be considered
  • vomiting without diarrhea should not be dismissed as just gastroenteritis
  • vomiting with the sensation of the room spinning suggests a vestibular cause
• the main issues for the ED doctor are:
  • deciding upon the main type of condition causing the vomiting as this will dictate Rx
  • control of the vomiting for symptom relief
  • Dx and Rx of underlying condition causing the vomiting
  • Mx of any complications

• located in the area postrema at the caudal end of the 4th ventricle.
• lies outside the blood brain barrier but is accessible to emetogenic stimuli in the blood or CSF.
• rich in dopamine D2 receptors and opioid receptors
• the main anti-emetic action of metoclopramide (Maxolon) is as a dopamine D2 antagonist at this site.

• via cranial nerve VIII
• rich in muscarinic M1 and histamine H1 receptors
• this is why vertigo is often association with nausea and vomiting

• mainly vagal and spinal afferents which are rich in 5-HT3 receptors
• intestinal irritation results in release of mucosal serotonin which activates these receptors and stimulate vagal input into both the vomiting centre and the CTZ

• central neural inputs have a role in vomiting due to stress, anxiety, anticipatory vomiting and psychiatric conditions

• gastroenteritis - usually has associated diarrhoea
• gastritis
• small bowel obstruction - usually frequent large volume bilious green vomiting
• large bowel obstruction - usually faeculent vomiting
• biliary colic
• the patient with acute abdominal pain in the ED

• cerebellar stroke
• vertigo - peripheral vs central
• motion sickness

• diabetic ketoacidosis (DKA)
• opiates and opioids
• chemotherapy
• coughing
• severe pain
• raised intracranial pressure (ICP)
• subarachnoid haemorrhage (SAH)
• hyperemesis gravidarum
• cannabinoid hyperemesis
• migraine
• overdose or poisoning
• cyclical vomiting syndrome
  • typically starts in early childhood around age 3-7yrs and may progress to adulthood
• bulimia

• neutrophilia which may confuse the clinical picture
• dehydration
• aspiration
• gastro-oesophageal reflux
• Mallory-Weiss tear
• recurrent or persistent vomiting:
  • dental damage
  • metabolic alkalosis with hypokalaemia
  • malnutrition