Vertigo and ion channels

Vertigo comes in many forms.  Some of these are inherited, due to changes in genes (mutations) that control brain balance or inner ear function.  These rare genetic causes of vertigo tend to run in families.  The brain uses electricity to transmit information, so it is important that the “wiring” is done properly and that balance information is sent accurately.  Nerves and neurons must be able to accumulate an electrical charge quickly and pass it on. 

To do this, there are small pores called ion channels in the nerves and neurons that allow charged particles (ions) to enter and exit quickly.  Elements like magnesium, sodium, chloride, calcium and potassium contribute ions that carry an electrical charge, and it is the movement of these ions that  provide the electricity your brain needs to communicate. 

In some families the ion channels have mutations that interfere with these channels, either making the channels too leaky or blocking them.  These channelopathies mean the affected nerves do not perform perfectly. There are many different genes that can be affected, and for each gene, there are several mutations that can have similar effects.

Episodic ataxias are channelopathies that result in spells of imbalance, usually noticed as staggering gait lasting minutes to hours.  The range of symptoms can be very different between types.  However, within a family the spells tend to resemble each other. Symptoms to watch for include migraines, epilepsy, vertigo spells, spells of weakness or muscle twitching, and abnormal eye movements (especially nystagmus in between spells).  Every family follows its own pattern and may not have all the symptoms found in other families. 

If you have spells of vertigo with staggering, and there are other family members who have suffered from this, it is worth seeing a neurologist to determine whether you have a familial ataxia.  Many of the episodic ataxias respond to acetazolamide, a drug that changes the pH of the brain and seems to improve channel function in affected people.  Other medications have also been found that are useful in certain families.