Management of Nausea and Vomiting Flashcards
What is nausea?
The unpleasant feeling of the need to vomit
What may (or may not) nausea be accompanied by?
Autonomic symptoms
What is vomiting?
The forceful expulsion of gastric contents through the mouth
What % of patients who undergo chemotherapy experience nausea or vomiting?
70-80%
What % of patients who undergo chemotherapy experience anticipatory vomiting?
10-40%
What are the categories of factors that influence the incidence and severity of chemotherapy induced emesis?
- Specific chemotherapeutic drug
- Patient variables
What factors about the specific chemotherapeutic drug can influence chemotherapy induced emesis?
- Dose
- Route
- Schedule of administration
What patient variables increase the risk of chemotherapy induced emesis?
- Young patients
- Women
What brainstem sites have key roles in the vomiting reflex pathway?
- Chemoreceptor trigger zone
- Vomiting centre
Where is the chemoreceptor trigger zone situated?
In the area postrema
What is the area postrema?
A circumventricular structure at the caudal end of the fourth ventricle
Is the area postrema inside or outside the blood brain barrier?
Outside
What is the result of the area postrema being outside the blood brain barrier?
It can respond directly to chemical stimuli in the blood or CSF
Where is the vomiting centre found?
In the lateral reticular formation of the medulla
What is the role of the vomiting centre?
- Co-ordinates the motor mechanisms of vomiting
- Responds to different afferent inputs
What afferent inputs does the vomiting centre respond to?
- Vestibular system
- Periphery (pharynx and GIT)
- Higher brainstem cortical structure
How do chemotherapeutic agents exert their emetic actions?
Chemotherapy agents, or their metabolites, can directly activate the medullary chemoreceptor trigger zone or vomiting centre. They can also act peripherally to cause vomiting.
What neuroreceptors play a critical role in chemotherapy-induced emesis?
Several neurotransmitters, including dopamine receptor type 2 and serotonin type 3 (5-HT3)
What can trigger anticipatory vomiting?
- Colour or smell of chemotherapeutic drugs
- Stimuli associated with chemotherapy, such as cues in treatment room or the person administering the chemotherapy
What is the mechanism of anticipatory vomiting?
The triggers activate higher brain centres and trigger emesis
How do chemotherapeutic drugs act peripherally to cause vomiting?
They cause cell damage in the GI, releasing serotonin from the enterochromaffin cells of the small intestinal mucosa
How does the release of serotonin from damage enterochromaffin cells cause vomiting in chemotherapy?
The released serotonin activates 5HT3 receptors on vagal and splanchnic afferent fibres, which then carry sensory signals to the medulla, leading to an emetic response
How can you identity the cause of nausea and vomiting clinically?
Often, there are common patterns/syndromes
What % of patients will have more than 1 cause of N&V?
Up to 25%
What are the different causes of N&V that lead to different patterns?
- Impaired gastric emptying
- Chemical/metabolic disturbances
- Raised ICP
- Constipation
- Malignant bowel obstruction
What are the clinical features of nausea caused by impaired gastric emptying?
- Epigastric discomfort
- Reduced appetite/satiety
- Post-prandial or bloating/audible splash
- Intermittent vomiting that eases nausea
- Large volume vomits that may contain food
What are the causes impaired gastric emptying in cancer?
- Causes associated with cancer
- Drugs
- Gastroenterostomy
- Autonomic neuropathy
What are the causes of impaired gastric emptying associated with the cancer?
- Locally advanced cancer
- Lymph node enlargement
- Liver mets
- Ascites
Give 2 examples of drugs that can cause delayed gastric emptying
- Morphine
- Anti-cholinergics
What are the clinical features of nausea caused by chemical/metabolic disturbances?
- Persistent nausea, aggravated by the sight and smell of food
- Nausea unrelieved by vomiting
- Drowsiness/confusion
What are the causes of chemical/metabolic disturbance in cancer?
- Drugs
- Renal or hepatic failure
- Hyponatraemia
- Hypercalcaemia
- Sepsis
- Tumour toxins
What drugs can cause chemical/metabolic disturbance?
- Opioids
- Antibiotics
- SSRIs
- Digoxin
What are the clinical features of nausea caused by raised ICP?
- Nausea worse in morning
- Projectile vomiting
- Worse on head movement
- Headache
What are the causes of raised ICP in cancer?
- Cerebral mets
- Cerebral haemorrhage
- Meningeal disease
What are the clinical features of nausea caused by constipation?
- Nausea and faeculent vomiting
- Abdominal distention
What are the causes of constipation in cancer?
- Drugs
- Immobility
What are the clinical features of malignant bowel obstruction?
- Intermittent vomits that may relieve nausea
- Large volume vomits, may be bilious or faeculent
- Abdominal cramps and altered bowel habit
- Abdominal distention
- Visible peristalsis
When is malignant bowel obstruction common?
In abdominal and pelvic cancer
Other than abdominal and pelvic cancer, what are the causes of malignant bowel obstruction?
- Autonomic neuropathy
- Carcinomatosis
What is carcinomatosis?
dunno might add it in when i have wifi
What are the physical consequences of nausea and vomiting?
- Dehydration
- Malnutrition
- Anorexia
- Weight loss
- Insomnia
What are the psychological consequences of nausea and vomiting?
- Anxiety
- Depression
- Anger
Why should nausea be taken serious?
It can be debilitating, and may be more distressing than pain
What effect might nausea and vomiting have on compliance?
Nausea and vomiting, or fear of, may lead to rejection of potentially curative anti-neoplastic treatment
What should be done in order tailor the pharmacological management of N&V?
You should identify the likely mechanism causing the N&V, and choose an appropriate drug to block the relevant receptor
What drugs can be used for acute emesis (<24 hours) caused by chemotherapy?
- Ondansetron
- Dexamethasone
What drugs can be used for delayed emesis (>24 hours) caused by chemotherapy?
- Ondansetron and/or dexamethasone
- Prochlorperazine
What drugs can be used for anticipatory vomiting?
Lorazepam
What drugs can be used for iatrogenic nausea and vomiting, e.g. opiates?
- Metaclopramide
- Haloperidol
What drugs can be used for nausea and vomiting caused by gastric irritation, including radiotherapy
- Lansoprazole
- Ondansteron
- Prochlorperazine
What drug can be used for nausea and vomiting caused by increased ICP?
Dexamethasone
What drug can be used for nausea and vomiting caused by gastric stasis/subacute bowel obstruction?
Metaclopramide
What drugs can be used for nausea and vomiting caused by obstruction?
- Cyclizine
- Haloperidol
- Dexamethasone
- Octreotide
How can nausea and vomiting with a metabolic cause be managed?
Correct the cause
