Lecture 1 Intro + Nausea And Vomiting Flashcards
What is Nausea
Feeling of “impending vomiting” or “need to vomit”
What is Retching
Spasmodic contractions of the diaphragm and intercostal muscles (respiratory muscles) with epiglottis closed
What is Vomiting (emesis)
Forceful oral expulsion of gastric contents
- GI retroperistalsis
- often associated with pallor, tachycardia, diaphoresis
Vomiting is triggered by ______ to the ________
Afferent impulses, vomiting centre
Explain the process of vomiting
- Contraction of diaphragm + abdominal muscles
- Relaxation of lower esophageal sphincter
- Peristalsis reverses direction: pushes stomach contents out of mouth.
- Soft palate is raised to prevent GI contents going into nasopharynx
- Epiglottis closed to prevent pulmonary aspiration
Afferent impulses (stimuli)
Chemical signals : drugs, toxins, metabolic disturbances, stimulate the chemoreceptor trigger zone
Visceral signals : irritation of distension of the GI tract sends signals via the vagus nerve and splanchnic nerves to vomiting centre
Vestibular input: motion sickness or inner ear disturbances stimulate the vestibular nuclei
Cortical input: psychological factors such as anxiety, fear, disgust, bad smells, sights
Emetic reflex involves these multiple receptors….
Serotonin
Dopamine
Acetylcholine
Histamin
Neurokinin-1
Cannabinoid
Opioid
What are the causes of vomiting and nausea
Motion sickness
NV of pregnancy
Postoperative nausea and vomiting
Medications
Antineoplastic induced nausea and vomiting
Radiation therapy
Diseases
What are the complications of vomiting
Fluid, electrolyte and metabolic alterations.
Aspiration pneumonia (Gastric contents go back into airway and lungs, causing infection)
Prolonged vomiting: nutritional deficiencies, esophagitis, lacerations, multiple purpuric lesions, dental caries
Three step Approach to nausea and vomiting, and goals of therapy
3 step approach:
1. recognize and correct and consequence of the vomiting
2. Identify underlying cause
3. Treat/manage underlying cause. If no etiology can be determined use empiric therapy to treat symptoms
Goals of therapy:
1. Prevent nausea and or vomiting
2. Prevent dehydration
3. Improve quality of life
4. Additional goals ( example. AINV Goal- maintain anticancer therapy schedule)
Assessment of NV and physical examination
Signs of dehydration:
- dry mucous membranes, increased thirst, reduced urination, weak/dizzy/lightheaded
- in children- few or no tears when crying, less wet diapers
Abdominal examination:
- abdominal pain/tenderness, abdominal extensions
Neurological examination:
-Head trauma/concussions,drug overdose, migraines
Signs of psychiatric cause:
- anxiety,panic, depression
Red flags associated with NV
Symptoms of dehydration
Persistent vomiting
Blood in vomit
Severe pain
Blood in stool
Altered mental status
Recent head trauma
Other considerations: difficulty swallowing, >55 years old, weight loss
Non pharm therapy for NV
Adequate hydration, adult needs 1-3L depending on how much lost during vomiting, electrolyte replacement may be needed for severe vomiting
Avoid noxious food or odors
Eat frequent, small meals
Decrease physical activity
Acupressure : sixth point along with pericardial meridian, approximately 3 finger breadths below wrist on inner forearm. 3-5 minutes of pressure every 4 hours.( wristbands have not been shown to be effective in motion sickness, less effective than manual pressure)
Histamine (H1) - Receptor Antagonists Role and agents in Canada
Role: Managment of motion sickness,vertigo, mild gastroenteritis
Agents:
Dimenhydrinate (Gravol), OTC
Diphenhydramine (Benadryl), OTC
Hydroxyzine (Generics), prescription
Histamine (H1) - Receptor Antagonists side effects
Drowsiness, confusion, dry mouth, blurred vision, urinary retention, constipation
Muscarinic Receptor Antagonists role and side effects
Role : motion sickness
Side effects: sedation,confusion,dry mouth, blurred vision, constipation, rash, urinary retention
Do not use in children less than 12 yrs old **
Dopamine (D2)- receptor Antagonists role and agents
Role : Severe Nausea and vomiting, NVP, PONV, AINV
Agents:
- Phenothiazines : prochlorperazine, chlorpromazine,promethazine
-Butyrophenones: haloperidol
-2nd generation antipsychotics: Olanzapine
- metoclopramide, domperidone.
ALL are RX except promethazine
Dopamine (D2) receptor Anagonists side effects
Drowsiness, extrapyramdal symptoms, postural hypotension’s, dry mouth, hyperpolactinemia, elderly more prone to EPS
Domperidone may be associated with a a small increased risk of _____ _______- or sudden cardiac death
Ventricular arrhythmias
T/F, domperidone should be used at lowest effected dose to a maximum daily dose of 30mg and for the shortest possible duration
True
Serotonin (5-HT3) Receptor Antagonists role and agents
Role : PONV, AINV, Radiation induced
Ondansetron, Granisetron, palonosetron
All available as IV or oral route
Serotonin ( 5-HT3) Receptor antagonists side effects
Constipation, headache, lack of energy, risk of serotonin syndrome, dose-dependent QT interval prolongation
Neurokinin-1(NK-1) Receptor Antagonists
-Oral- aprepitant (Emend)
- IV form is fosaprepitant
- oral combination - netupitant + palonosetron
Role: Used in combination with 5-HT3 antagonists and dexamethasone for AINV, can also be used in PONV
Glucocorticoids for NV
Dexamethasone- most common formulation used
Indication : PONV, AINV, Radiation induced NV
Side effects: note: usually used short term in NV, fluid and electrolyte disturbances, hyperglycemia, infections,psychosis
Cannabinoids in nausea
Nabilone (cesamet) 1-2mg twice daily orally
Role in AINV
Side effects: euphoria, sedation, dysphoria, hallucination
Medical cannabis in NV
Role in AINV
Evidence is limited with forms of medical cannabis in AINV, though few studies with THC only capsules
Commonly used NHP and side effects in NV
Ginger and Vitamin B6
Side effects: heartburn, diarrhea, mouth irritation, dermatitis
Dose: 1gram/day in divided doses BID
Drug interactions: anti-coagulants, antiplatletes- high doses may increase risk of bleeding
