Nausea and Vomiting (Part 1) Flashcards
Nausea
- Definition
Subjective feeling of the need to vomit
Retching
- Definition
Non voluntary spasmodic contraction of the body preparing to vomit
- Epiglottis closed
- Diaphragm and intercostal muscles contract
Vomiting (Emesis)
- Definition
Forceful oral expulsion of gastric contents
Regurgitation
Contents rise to the pharynx, no forceful ejection
Vomiting
- Process
- Contraction of diaphragm + abdominal muscle
- Relaxation of lower esophageal sphincter
- Peristalsis reverses direction, pushes stomach contents to mouth
- Soft palate is raised to prevent GI contents entering nasopharynx
- Epiglottis is closed to prevent pulmonary aspiration
Vomiting
- Soft Palate
Is raised to prevent GI contents from entering nasopharynx
Vomiting
- Epiglotis
Is closed to prevent pulmonary aspiration (Entry of food or liquid into lungs)
Afferent Impulses
- Chemical Signals
Drug, toxins, metabolic disturbances act as signals
- Chemoreceptor trigger zone (CTZ) in the brainstem is triggered
Afferent Impulses
- Visceral Signals
Irritation or distension in GI tract sends signals
- Sent via Vagus Nerve and Splanchnic Nerves to Vomiting Center
Afferent Impulses
- Vestibular Input
Motion sickness or inner ear disturbances stimulate Vestibular Nuclei
- Mediated by H1 (Histamine) and M1 (Acetylcholine) receptors
Afferent Impulses
- Cortical Input
- Psychological Factors like Anxiety, fear, or disgust
- Sensory Input like bad smell or sight
–> Activates the vomiting reflex
Receptors involved in Emetic Reflex
Serotonin (5-HT3)
Dopamine (D2)
Acetylcholine (Ach, M1)
Histamine (H1)
Neurokinin-1 (NK-1, Substance P)
Cannabinoid (CB1)
Opioid
Vomiting
- Complications
- Fluid, electrolyte, metabolic alterations
- Dehydration, cardiac arrhythmias - Aspiration Pneumonia
- Backflow of vomit into lungs - Prolonged Vomiting
Prolonged Vomiting
- Complications
- Malnutrition
- Esophagitis (Inflammation of esophagus)
- Lacerations at gastroesophageal junction
- Multiple purpuric lesions (pupils)
- Dental Erosion
Approach to NV
- Correct consequences of vomiting (dehydration, electrolyte imbalance)
- Identify and Treat underlying cause
- If no underlying cause use empiric therapy
NV
- Symptoms
- Are you experiencing N, V. or both
- Any abdominal pain, dizziness, fever, or diarrhea
- Any change appetite or weight
NV
- Characteristics
- Appearance of vomit
- Frequency and timing of vomit
- Severity of symptoms
NV
- History
- Unusual food/drinks
- New or recent medications
- Travel history
- Sick contacts
- Pregnancy
NV
- Onset
- Gradual or Sudden
NV
- Red Flags
- Dehydration
- Persistient vomiting
- Blood or coffee ground appearance in vomit
- Blood in stools
- Severe pain
- Altered mental status
- Recent trauma
NV
- Referral Considerations
- Difficulty swallowing
- Age > 55
- Unintentional weight loss
- Signs of prolonged vomiting
NV
- Nonpharm Options
- Hydration
- Avoid noxious odours or foods causing nausea
- Small and frequent meals
- Decrease physical activity
NV
- Acupuncture
3 to 5 minutes of pressure every 4 hours
- Helpful for mild NV, motion sickness, AINV, PONV
NV
- Acupuncture Wristbands
Have not shown to be effective in motion sickness
- Less effective than manual pressure
- No harm in trying for mild NV
