Migraine and Emesis.

Question 1

How long can a migraine last?

Answer 1

4-72 hours.

Question 2

In 1/4 of cases what is a migraine associated with?

Answer 2

An aura - a migrating visual or other sensory disturbance lasting up to an hour.

Question 3

In 60% of cases, what is a migraine proceeded by?

Answer 3

Prodromal signs such as - neck stiffness, hyperactivity, food craving, yawning.

Question 4

Migraine is what in nature and involves what?

Answer 4

Migraine is neurovascular in nature and involves changes in local brain blood flow.

Question 5

Pain results from what?

Answer 5

Activation of the trigeminal nerve terminals on blood vessels, usually associated with nausea.

Question 6

Migraine is associated with what type of dilation?

Answer 6

Brain arteriolar dilation and dilation of the temporal artery is seen during and after migraines.

Question 7

In attacks, sensory nerves, innervating the cerebral blood vessels are activated to release what and how?

Answer 7

To antidromically release CGRP, NO etc …

Question 8

The aura involves what?

Answer 8

A wave of excitation starting in the occipital cortex and spreading slowly at 2-3mm/min.

Question 9

The wave of excitation created during an aura and associated visual hallucinations follow what?

Answer 9

A path across the visual field that is reproducible within the same individual.

Question 10

Migraine with aura is a predisposing factor for what?

Answer 10

A stroke.

Question 11

What is used for acute treatment of migraines?

Answer 11

Analgesics and NSAIDs.

Question 12

What drugs cause constriction of cranial blood vessels? What is wrong with them?

Answer 12

Triptans for eg: sumatriptan - which are 5-HT1b and 5-HT1d receptor agonists. They carry cardiovascular risk.

Question 13

What preventative therapy can be used for the treatment of migraines?

Answer 13

Avoid stress and certain foods. Drugs wise - B-blockers, calcium channel blockers, pre-menstrual oestrogen and anticonvulsants can all be effective. NICE recommends acupuncture.

Question 14

What symptoms often accompany nausea?

Answer 14

Cold sweat, pallor, salivation, self absorption, loss of gastric tone, duodenal contractions and reflux of intestinal contents into the stomach often accompany nausea.

Question 15

Emesis is generated and controlled by what?

Answer 15

The vomiting centre.

Question 16

Where is the vomiting centre situated?

Answer 16

In the medullary reticular formation.

Question 17

The group of neurons in the vomiting centre generate and receive what?

Answer 17

Generate motor components of the vomiting centre and receive inputs that trigger the reflex.

Question 18

What are 5 main causes of nausea and vomiting?

Answer 18

Iatrogenic, motion sickness and Meniere’s disease, pregnancy, poisoning, gastroenteritis, meningitis and intracranial haemorrhage, bulimia nervosa.

Question 19

Where is the chemoreceptor trigger zone situated?

Answer 19

At the base of the fourth ventricle.

Question 20

What receptors does the the chemoreceptor trigger zone contain?

Answer 20

D2, 5-HT3, opioid and ACh.

Question 21

What is the major output transmitter?

Answer 21

Neurokinin - substance P.

Question 22

What other inputs to the chemoreceptor trigger zone are there?

Answer 22

Area postrema - detects blood chemicals as no BBB.
Vestibular system via CN VIII.
Vagal nerve afferents activated when pharynx irritated, leads to gag reflex.
Intracranial pressure receptors mediating nausea after head injury or meningitis.

Question 23

List some drugs that are used to control nausea and vomitting.

Answer 23

5-HT3 antagonists, Neurokinin antagonist, D2 antagonist, anti-cholinergics, Anti-histamines, H3 antagonist, cannabanoid agonist.