Flashcards in Palliative care in gynaecology Deck (27):
A women who is undergoing treatment for ovarian cancer complains of nausea. She says she doesn't feel nausea constantly but it comes on quite suddenly and she vomits a large amount, after which she feels better. What is the most likely cause of her nausea?
Impaired Gastric emptying
A women undergoing chemotherapy complains of constant nausea with little relief from vomiting. Is the cause msot likely to originate in the gut, vestibular system or chemoreceptor trigger zone.
Chemoreceptor trigger zone
What is the chemoreceptor trigger zone?
An area of the medulla that receives inputs from blood borne drugs or hormones and then communicates with structures in the vomiting centre to cause vomiting.
Where is the chemoreceptor trigger zone?
Outside of the blood brain barrier!
Describe the pathophysiology of vomiting?
1. Triggers reach the CTZ
2. CTZ then stimulates the vomiting centre. Vomiting centre can also be stimulated by other areas such as the vestibular centre, the enteric nervous system and higher brain centres. Mainly drugs that trigger the CTZ.
3. Motor outputs cause contraction of the diaphragm and anterior abdominal muscles. There is relaxation of the oesophageal sphincter and ejection of gastric contents through the open upper oesophageal sphincter.
What receptors are found on the CTZ?
List the various inputs to the vomiting centre
2. Vestibular system
3. Vagus nerve (gag reflex)
4. Enteric nervous system
Is the CTZ inside or outside of the blood brain barrier?
What anti-emetics are used if the nausea is caused by impaired gastric emptying and how do these drugs work?
- Dopamine (acts at CTZ)
- 5HT3 receptor antagonist
-5HT4 agonist (Pro kinetic)
- Peripheral dopamine D3 and D4 receptor antagonist (Acts at CTZ and as a prokinetic)
What two neurotransmitters mediate the nausea felt due to impaired gastric emptying?
Which antiemetic is used to help with the regurgitation seen with some cancer treatments?
Dexamethasone (5HT3 antagonist)
Which antiemetics are used to help with the nausea and vomiting caused by the chemical or metabolic effects of chemotherapy?
- D2 receptor antagonist
Which antiemetics are used to help with the nausea and vomiting caused by cerebral disease?
Dexamethasone (5HT3 antagonist)
Cyclizine (H1 receptor antagonist)
What neurotransmitters are thought to cause the nausea and vomiting associated with cerebral disease?
What neurotransmitters are thought to cause the nausea and vomiting associated with the vestibular system?
Which antiemetics are used to help with the nausea and vomiting caused by the vestibular system?
Prochlorperazine (D2 receptor antagonist)
Which is the most likely cause for nausea that is worse on movement and associated with tinnitus?
Which 5HT3 receptor antagonist is used to treat radiation and chemotherapy induced emesis?
What is malignant bowel obstruction?
Clinical evidence of bowel obstruction in the setting od a diagnosis of intra abdominal cancer or non intra abdominal cancer with clear intraperitoneal disease.
A patient with ovarian cancer presents with abdominal distension and vomiting. One examination you hear tinkling bowel sounds.
Malignant bowel obstruction
What drug might help in malignant bowel obstruction?
Which drug helps with colicy pain?
Hyoscine Butylobromide (Buscopan)
Which anti emetic would you give if there was an incomplete metabolic bowel obstruction and no colic in an ovarian cancer patient?
Which two drugs help to reduce GI secretions?
Buscopan (Hyoscine Butylbromide)
Octreotide - somatostain analogue
Which drugs help to soften the stool in partial bowel obstruction?
Which drug is used in opiod induced constipation?