About episodic ataxia

What is episodic ataxia?

The hereditary ataxias are a group of neurological disorders (ataxias) of varying degrees of rarity that are inherited, in contrast to a related group of neurological disorders that are acquired through accidents, injuries, or other external agents. The hereditary ataxias are characterized by degenerative changes in the brain and spinal cord that lead to an awkward, uncoordinated walk (gait) accompanied often by poor eye-hand coordination and abnormal speech (dysarthria). Hereditary ataxia in one or another of its forms may present at almost any time between infancy and adulthood.

The classification of hereditary ataxias is complex with several schools of thought vying for recognition. 

This classification is based on the pattern of inheritance or mode of genetic transmission of the disorder: i.e., autosomal dominant, autosomal recessive and X-linked. The autosomal dominant ataxias, also called the spinocerebellar ataxias, are usually identified as SCA1 through SCA31. Also included are several "episodic ataxias", as well as a very rare disorder known as DRPLA (dentato-rubro-pallido-luysian atrophy). This report deals with the autosomal dominant hereditary ataxias. There are fewer autosomal recessive hereditary ataxias than autosomal dominant hereditary ataxias, and X-linked forms of ataxia are very rare.

At one time, all autosomal dominant ataxias were called Marie's ataxia and all autosomal recessive ataxias were called Friedreich's ataxia. This is no longer appropriate because there is now much more accurate information about these diseases.

What are the symptoms for episodic ataxia?

Poor hand-eye coordination symptom was found in the episodic ataxia condition

Symptoms of EA occur in episodes that can last several seconds, minutes, or hours. They may occur as little as once per year, or as often as several times per day.

In all types of EA, episodes are characterized by impaired balance and coordination (ataxia). Otherwise, EA is associated with a wide range of symptoms which appear to vary a lot from one family to the next. Symptoms can also vary between members of the same family.

Other possible symptoms include:

  • blurred or double vision
  • dizziness
  • involuntary movements
  • migraine headaches
  • muscle twItching (myokymia)
  • Muscle Spasms (myotonia)
  • muscle cramps
  • muscle weakness
  • Nausea and vomiting
  • repetitive eye movements (nystagmus)
  • ringing in the ears (tinnitus)
  • seizures
  • slurred speech (dysarthria)
  • temporary Paralysis on one side (hemiplegia)
  • tremors
  • vertigo

Sometimes, EA episodes are triggered by external factors. Some known EA triggers include:

  • alcohol
  • caffeine
  • diet
  • fatigue
  • hormonal changes
  • illness, especially with fever
  • medication
  • physical activity
  • stress

More research needs to be done to understand how these triggers activate EA.

What are the causes for episodic ataxia?

Episodic Ataxia type 1

EA1 is caused by a mutation in the KCNA1 gene, which carries the instructions to make a number of proteins required for a potassium channel in the brain. Potassium channels help nerve cells generate and send electrical signals. When a genetic mutation occurs, these signals may be disrupted, leading to ataxia and other symptoms.

This mutation is passed on from parent to child. It’s autosomal dominant, which means that if one parent has a KCNA1 mutation, each child has a 50 percent chance of getting it, too.

Episodic Ataxia type 2

Similar to EA1, EA2 is caused by an autosomal dominant genetic mutation that’s passed on from parent to child. In this case, the affected gene is CACNA1A, which controls a calcium channel.

This same mutation is associated with other conditions, including familiar hemiplegic migraine type 1 (FHM1), progressive ataxia, and spinocerebellar ataxia type 6 (SCA6).

What are the treatments for episodic ataxia?

Episodic ataxia is diagnosed using tests such as a neurological examination, electromyography (EMG), and genetic testing.

After diagnosis, EA is typically treated with anticonvulsant/antiseizure medication. Acetazolamide is one of the most common drugs in the treatment of EA1 and EA2, though it’s more effective in treating EA2.

Alternative medications used to treat EA1 include carbamazepine and valproic acid. In EA2, other drugs include flunarizine and dalfampridine (4-aminopyridine).

Your doctor or neurologist might prescribe additional drugs to treat other symptoms associated with EA. For instance, amifampridine (3,4-diaminopyridine) has proved useful in treating nystagmus.

In some cases, physical therapy may be used alongside medication to improve strength and mobility. People who have ataxia might also consider diet and lifestyle changes to avoid triggers and maintain overall health.

Additional clinical trials are required to improve treatment options for people with EA.

Is there a cure/medications for episodic ataxia?

There’s no cure for any type of episodic ataxia. Though EA is a chronic condition, it doesn’t affect life expectancy. With time, symptoms sometimes go away on their own. When symptoms persist, treatment can often help ease or even eliminate them altogether.

Talk to your doctor about your symptoms. They can prescribe helpful treatments that help you maintain a good quality of life.

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