2. Definitions
Nausea : Feeling of needing to vomit / unpleasant feeling preceding vomiting
Vomiting/ Emesis : Expulsion of gastric contents by forceful contractions of
abdominal and thoracic muscles
4. Pathophysiology
Neurons in medulla oblongata(area postrema) activated in sequence to induce vomiting
Receptors : D2, 5HT3 , H1, M1
1. Chemoreceptor trigger zone (CTZ) in 4th Ventricle - Drugs , Toxins
2.Vagal/Visceral afferents : Vomiting induced by parts of GI / extra GI
3. Vestibular Nuclei : Motion sickness
4. Higher Centres : Pain , Smell, Memory
Same pathways for Nausea and Vomiting - Intensity of stimulation different
5.
6.
7. Stages of Vomiting
1. Nausea : Unpleasant sensation preceding vomiting associated with
hypersalivation , repetitive swallowing , tachycardia
2. Retching: Gastric/Esophagus relaxation with rhythmic , synchronous
contraction of diaphragm and abdominal (External oblique & Abdominal
rectus) muscles - creates pressure gradient
3. Vomiting : Actual retrograde expulsion of gastric content in response
to the pressure gradient created by retching - glottis closes - prevents
aspiration.
* All three don’t need to be present*
8. Diagnosis of Nausea and Vomiting
The list is - Very large
Every organ pathology can cause Nausea and Vomiting
Can narrow down by history and examination
9. Important History Points
Number of Episodes
Interval between episodes
Timing of episodes
Contents of Vomit - BIle / Blood stained
If blood + : Color of Blood
LMP in reproductive age group females
Prior abdominal surgeries - risk of obstruction due to adhesion formation
11. Physical Examination
Vitals
Hydration status (especially in multiple episodes):
Look for icterus
Complete Abdominal examination - IAPP
If association with vertigo - diff Central vs Peripheral
ECG : If indicated
13. Imaging Indicated if
Central Cause of Vomiting - CT / MRI Brain
CT Chest / Chest X ray - Suspect Esophageal Rupture (Boerhaave syndrome)
Abdominal Imaging if Vomiting secondary to bowel obstruction , kidney stones ,
USG abdomen - if suspecting Pancreatic / Gallbladder / Hepatic/ Appendix / Renal
pathology
14. Treatment in ER
ABC - stabilize the patient
Both ondansetron and prochlorperazine are equally effective to stop vomiting
Antihistamine : Motion sickness / Labrirythitisis induced
Metoclopramide : If Vomiting + Headache
If dehydrated : Oral / IV fluids
Take History and Examination
Labs
Imaging if indicated
15. Complications
1. Hypochloremic, Hypokalemic, Metabolic alkalosis - due to H+ ion loss
Alkalosis → Increased Sodium Bicarb to Kidney (distal Tubules) →
Secondary Hyperaldosteronism causes increased NaCo3 reabsorption and K+
excretion
2. Esophageal tear : Complete: Boerhaave Syndrome
Partial: Mallory Weiss
3. Dehydration : Chronic / massive vomitings