From the Journals

Researchers describe first cases of episodic visual snow associated with migraine



Episodic visual snow was tied to migraine attacks in a case series of three adults who denied any visual snow outside of the migraines, based on data collected at an outpatient headache center.

Visual snow, a condition in which patients experience visual distortion of tiny, flickering dots resembling analog television static, is often a comorbid condition in migraine patients with and without aura. However, “to our knowledge, this is the first report of patients with an episodic form of visual snow strictly occurring with migraine attacks,” wrote Julius Hodak, MD, of the University of Bern (Switzerland) and colleagues.

In a research letter published in JAMA Neurology, the investigators described 3 adults with histories of migraine but no aura who presented to a tertiary headache center between January 2016 and December 2017, in addition to 1,934 adults with migraine but no visual snow. The three patients initially presented with headaches, and neurologic and MRI results were normal.

Two patients experienced black and white episodic visual snow and one experienced black and yellow visual snow. In one patient, visual snow occurred for less than 2 minutes before and during a migraine attack. The other two patients experienced visual snow during the entire migraine attack.

Based on these patients, the researchers proposed distinguishing episodic visual snow from the distinct disorder of visual snow syndrome, in which patients experience continuous visual snow and other visual symptoms.

In addition, the cases were notable because of the lack of aura in the patients, the researchers wrote.

“In clinical practice, a detailed history in patients reporting visual flickering is therefore necessary to differentiate aura from [episodic visual snow],” they added, because an aura diagnosis would affect patient guidance on contraception use or the timing of triptans.

Dr. Hodak had no financial conflicts to disclose. The study was supported by Deutsche Migräne-und Kopfschmerzgesellschaft, Eye on Vision Foundation, and Baasch-Medicus Foundation.

SOURCE: Hodak J et al. JAMA Neurol. 2019 Nov 25. doi: 10.1001/jamaneurol.2019.4050.

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