Nausea & Vomiting Causes Symptoms Pathophysiology Neural Pathways Complications Approach in ER Diagnosis Labs History Points Treatment in ER

1. Nausea & Vomiting
By Dr. Abraham Mallela
1st Year MRCEM Resident

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

3. Causes
CNS: IC Bleeds Increased ICP , Tumors , SOL’s, Migraine
Endocrine : Diabetic Ketoacidosis , Hyponatremia, Elevated Beta HCG in
Pregnancy (Morning sickness)
GI : Binge eating/alcohol , Gastroenteritis , GI Bleed, any itits, Bowel Obstruction ,
Boerhaave’s syndrome,
Psychiatric Conditions : Bulimia Nervosa , Anxiety
Iatrogenic : Medications , Toxins
Others: Severe pain , MI, sepsis , Travel Induced, Poison induced

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

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

10. Associated symptoms : Abdominal pain , fever , loose stools , headache , chest
pain , neurological manifestation ()
Neurological Symptoms - Headache , Visual disturbance, vertigo - indicate central
cause
Fever, abdominal pain , loose stools - can indicate gastroenteritis - ask for H/O
outside food intake / alcohol

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

12. Labs
Sr. Electrolytes & creatinine
ABG - for Lactate - Sepsis & Shock
Urine Examination
Lipases
LFT

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

16. References
Rosen's - Chapter 26 - Page # 230
Tintinalli's - Chapter 72 - Page # 489

17. Thank You , Cheers!