First, persistent migraine aura (PMA) is diagnosed when other causes are ruled out. But as we’ve said there are a number of things that can cause visual snow (VS).
Doctors will take a careful drug history for patients with VS, because one cause is hallucinogenic drugs. The drug may only have been taken once, and time may have passed since it was taken, but it can have permanent effects.
Optic neuritis, an inflammation of the optic nerve, can also be a cause. Optic neuritis usually develops from an autoimmune disorder. Read more about optic neuritis here.
There are many other things that can be involved – even vitamin deficiencies.
Dr. Klaus Podoll, Dr. Markus Dahlem and Sofia Greene list common tests that are done for persistent aura symptoms here. These include:
- Ophthalmologic examination
- Neurological examination
- Psychiatric examination
- Thorough headache history and family history
- Thorough drug history (including illegal drugs, especially hallucinogens: LSD, Ecstasy, mushrooms, other?)
- CAT or MRI of head (the MRI is important to rule out what is called a migrainous infarction)
Other examinations may follow, including an EEG, evoked potentials (a testing of the functioning of the nervous system), blood work, and a lumbar puncture.
Obviously, if anything shows up on these tests, you’ll be following that up.
Assuming these treatments are out of the way, there are some treatments that have been tried, with some success. There is no tried-and-true established treatment, but some options include:
- valproic acid
- lamotrigine (particularly for VS not classified as PMA)
- topiramate (Topamax)
Sometimes injections of furosemide (frusemide) are used, if other treatments fail. Clonazepam is also used for patients who have symptoms from hallucinogenic drugs.
Do you have experience with ongoing migraine aura, or visual snow? Have you found anything that has helped? How did the symptoms start?