Familial Hemiplegic Migraine Attacks May Be Associated With Cortical Swelling

A retrospective study published in the Journal of the Neurological Sciences utilized various tools to determine that “acute familial hemiplegic migraine type 2 (FHM2) attacks can be associated with cortical swelling of the affected cerebral hemisphere.”

Researchers performed a retrospective review of 4 participants from 3 unrelated families who suffer from FHM2 attacks. The researchers reviewed data from 6 different attacks taken at different times post-attack onset. 

Family A included participant 1, a 58-year-old father, and participant 2, his 29-year-old son. Participant 1 was admitted to the hospital twice within a 9-year span as a result of severe FHM attacks (with long duration periods). Serial cranial magnetic resonance imaging (cMRI) scan was administered to participant 1 twice during both attacks: for attack 1, at day 11 post-attack onset and 8 months post-attack, and for attack 2, at day 2 post-attack onset and 9 days after presentation of cortical swelling symptoms.

The first cMRI post-attack 1 showed diffuse cortical swelling, hyperintensity, cortical thickening, and diffusion-weighted imaging. Also, an electroencephalogram (EEG) result showed frontal temporal slowing. The second cMRI post-attack 1 showed resolution of the uncharacteristic symptoms. The first cMRI post-attack 2 was inconspicuous; however, CT-perfusion showed hyperperfusion over the left hemisphere and increased blood volume and flow. The second cMRI post-attack 2 showed left hemisphere cortical swelling and dilation of vessels.

Participant 2 experienced the first attack at 10 years with the duration of the episode lasting for a few hours. For the most recent attack, cMRI was performed day 5 post-onset and showed cortical sensitivity. 

The first cMRI post-attack 1 was performed on participant 3 (19 years of age) at day 5 post-admission showing “slight cortical hyperintensity in T2, FLAIR- and diffusion-weighted imaging over the right hemisphere, in combination with cortical swelling over the right hemisphere.” The second attack (3 years later) did not qualify as hemiplegic attack; however, CT perfusion studies performed 5 days post-attack onset showed mildly increased blood flow and volume.

Lastly, participant 4 (45 years of age) was analyzed during an attack that was a shorter duration and less intense in comparison to the other participants. There were no remarkable results noted. 

Study limitations include the lack of availability of contrast-enhanced cMRI, availability and timing of applied imaging techniques due to retrospective format, and the small number of perfusion data sets.

Overall, researchers conclude that “[o]ur retrospective data emphasize that acute FHM2 attacks can be associated with cortical swelling of the affected cerebral hemisphere on cMRI. These changes seem to occur during the later stages of attacks and may be a correlate of prolonged attack duration. To gain further insights, also regarding the complex characteristics of hemodynamic changes, prospective evaluation of larger cohorts with serial cMRI and CT-perfusion is necessary.”

Reference

Roth C, Ferbert A, Huegens-Penzel M, Siekmann R, Freilinger T. Multimodal imaging findings during severe attacks of familial hemiplegic migraine type 2.  J Neurol Sci. 2018; 392:22-27.