Motion Sickness (Vestibular Disorder)

Question 1

Background

Answer 1

Motion sickness describes a combo of symptoms.
NO functional vestibular system = immune to motion sickness.

Can also affect blind people.

Inner ear is critical for the development of motion sickness. Due to its role in detecting motion

Question 2

Signs and Symptoms

Answer 2

• pale skin.
• cold sweat.
• dizziness.
• increase in saliva.
• vomiting.

Question 3

Possible Causes

Answer 3

Common hypothesis for the cause is that it functions as a defence mechanism against neurotoxins. The body, eyes and ears send conflicting messages to the brain. The CTZ in the medulla is triggered by neurotransmitters (histamine, acetylcholine, dopamine and serotonin) which send a signal that poisons have been ingested. When feeling motion but not seeing it (for example, in a ship with no windows), the inner ear transmits to the brain that it senses motion, but the eyes tell the brain that everything is still. As a result of the discordance, the brain will come to the conclusion that the individual is hallucinating and further conclude that the hallucination is due to poison ingestion. The brain responds by inducing vomiting, to clear the supposed toxin.

When the body is moved intentionally, EG, when we walk, the input from all three pathways is coordinated by our brain. When there is unintentional movement of the body, as occurs during motion when driving in a car, the brain is not coordinating the input, and there is thought to be discoordination or conflict among the input from the three pathways.

Question 4

Treatment (NON pharmacological)

Answer 4

• Ask the patient to fix their eyes on the horizon or tell the patient to distract themselves
• Ask patient to try to remain as still as possible, choosing a cabin or seat in the middle of a boat or plane, because this is where the least movement is experienced. Using a pillow or headrest to help keep the head as still as possible can help.
• Looking at a stable object – eg, the horizon, eyes closed
• Fresh air
• Relaxation techniques – count backwards, focus
• Stay calm
• Avoid eating large meal or drinking alcohol before travelling and keeping well hydrated throughout with water
• Eating ginger
• Acupressure bands

Question 5

Treatment (Pharmacological)

Answer 5

Preventatives: BNF:
Antiemetics - Hyoscine hydrobromide (anticholinergic/antimuscranic) - prevent N+V, vertigo

Antihistamine - less sedating (cinnarzine, cyclizine), more sedating (promethazine)