Basic approach to nausea and vomiting- gastroenterology lecture.

1. Nausea and
vomiting
Dr. Hritvik Jaiswal
PG Resident
General Medicine
PMCH, Udaipur

2. Definitions
• Nausea- unpleasant subjective sensation – a feeling of impending
vomiting in the epigastrium or throat.
• Retching- spasmodic and abortive respiratory movements with the
glottis closed.
• Vomiting- partially voluntary act of forcefully expelling gastric or
intestinal contents through the mouth.
• Regurgitation- effortless reflux of gastric contents into the mouth
which is not usually associated with forceful ejection typical of
vomiting

3. Pathophysiology
• Emetic center /vomiting center- located in the medulla- specifically in
the dorsal portion of the lateral reticular formation.
• Other medullary nuclei controlling respiratory, pharyngeal, facial,
tongue muscles.
• Initiation via following elements-
• NK1
• 5HT3
• Endocannabinoid CB receptors
• H1 , M1

6. Mechanism
1. Inspiratory thoracic and abdominal wall contracts
2. Increased intra thoracic and intra abdominal pressures
3. Evacuation of stomach contents
During emesis, slow waves ( distally migrating gut contractions ,
3cycles/min in stomach and 11 cycles/min in duodenum) are abolished
and replaced by orally propagating spikes – Retrograde contactions

8. Activators of emesis
Stimuli Receptor acting via Pathway involved
Unpleasant thoughts/ smells NK1 , CB1 Brain pathways
Motion sickness, inner ear diseases M1, H1 Labyrinthine pathways
Gastric irritants/ Cytotoxics 5HT3 vagal afferent nerves
Bowel obstruction/ mesenteric
ischemia
Non- gastric afferents
Blood borne stimuli-
Emetogenic drugs, bacterial toxins,
uremia, hypoxia, Ketoacidosis
5HT3, M1 H1 D2 Area postrema ( CTZ)

10. Intestinal Pseudo- obstruction:
• Retention of food residue and secretionà bacterial overgrowth à
nutrient malabsorption
• Causes nausea, vomiting, bloating, pain abdomen, altered defecation
• Can be due to- idiopathic, inherited, Scleroderma, Amyloidosis,
Paraneoplastic syndrome.

11. Functional gastroduodenal disorders
• Chronic Nausea Vomiting Syndrome: Bothersome nausea for at least
1 day and/ or one or more than one vomiting episodes weekly in the
absence of an eating disorder or psychiatric disease.
• Cyclic Vomiting Syndrome (CVS) :
• 3-14% of unexplained nausea and vomiting.
• Episodes of relentless vomiting, associated with migraine
• Cannabinoid hyperemesis Syndrome ( CHS):
• Cyclical vomiting in men with long standing use of cannabis
• Resolves with discontinuation

12. Approach to nausea and vomiting
History-
• Drugs/ toxins/ infections : Acute
• Established illness : Chronic
Timing:
• Gastroparesis and pyloric obstruction- within an hour of eating
Intestinal Blockage- later ( few hours)
• Rumination Syndrome- within minutes

13. • Hematemesis: Ulcer, malignancy, Mallory
Weiss tear
• Feculent: Distal intestinal/ colonic
obstruction
• Undigested food : Zenker’s diverticulum /
achalasia

14. • Vomiting relieving abdominal pain: Bowel obstruction
No relief – Pancreatitis or cholecystitis
• Weight loss- Malignancy
• Prolonged hot baths: CHS / CVS
• Headache/ visual changes: Intracranial cause
• Vertigo/ tinnitus- Labyrinthine diseases

15. Examination-
• Orthostatic hypotension and decreased skin turgor- intravascular fluid
loss
• Pulmonary abnormalities- Aspiration of vomitus
• Bowel sounds- absent: Ileus
• High pitched rushes- Bowel obstruction
• Succussion splash- gastroparesis/ pyloric obstruction
• Involuntary guarding- Inflammation
• Fecal blood- Ulcer/ ischemia/ tumor
• Palpable mass- Neoplasm

17. Investigations
• Routine- Serum electrolytes, LFT, Amylase, Lipase
• Supine/ standing X-rays-
• Dilated air filled bowel loops- Ileus
• Air fluid levels- Small bowel obstruction
• UGI Endoscopy- Ulcers, malignancies
• Barium swallow, USG
• CT ,MRI
• CT- angiography: Mesenteric ischemia

20. • GI motility testing- Motor
disorders
• Gastric scintigraphy , 13C gastric
emptying breath test:
gastroparesis
• Wireless motility Capsules
• Small Intestinal manometry –
Neuropathic vs Myopathic cause
• Ambulatory esophageal PH
testing
• High resolution manometry

21. Treatment
Correction of Metabolic Complications
• Normal saline solution to correct deficits (and in addition to maintenance
fluids) with potassium supplementation (60 to 80 mEq/24 hr).
• The saline can be administered with glucose (e.g., 5% dextrose in normal
saline), and in some cases a 10% glucose solution may be required.
• When oral intake can be resumed, glucose-containing fluids are preferred
because they are easily absorbed from the intestine.
• A split-meal, low-fat, and low-fiber solid diet can be gradually introduced.

22. Pharmacologic treatment
• Central Antiemetic agents
• Peripheral prokinetic agents

24. Take- home message
• When approaching a patient with nausea and vomiting try to-
1. Replace lost fluids
2. Identify cause: surgical or medical
3. Treat the specific cause

25. Thank you