Overview
Familial hemiplegic migraine (FHM) is a rare subtype of migraine characterized by recurrent attacks often accompanied by motor weakness on one side of the body. It is primarily linked to mutations in genes encoding calcium channel subunits, such as CACNA1A 1.Diagnosis
Genetic Testing: Identification of mutations in CACNA1A, ATP1A2, or SCN1A genes 1.
Clinical Criteria: Recurrent attacks with typical aura including focal neurological symptoms lasting <72 hours, often involving motor deficits 1.
Differential Diagnosis: Exclude other causes of hemiplegic episodes such as transient ischemic attacks or epilepsy 1.Management
First-Line Treatments:
- Preventive Medications: Beta-blockers (e.g., propranolol), anticonvulsants (e.g., valproate), and calcium channel blockers (e.g., verapamil) 1.
Adjunctive Treatments:
- Acute Attacks: Triptans may have variable efficacy; sumatriptan showed diminished effectiveness in trigeminal pathways in FHM1 models 1.
- CGRP Pathway: Further exploration of CGRP receptor antagonists may be warranted despite current limitations 1.Special Populations
Pregnancy: Limited data; close monitoring and individualized management are advised 1.
Pediatrics: Early diagnosis and tailored preventive strategies are crucial; genetic counseling recommended 1.
Elderly: Consider comorbidities and adjust preventive treatments accordingly; close follow-up essential 1.
Comorbidities: Management should integrate strategies for coexisting conditions, potentially influencing choice of preventive medications 1.Key Recommendations
Genetic Testing for Diagnosis: Confirm diagnosis through genetic testing for mutations in CACNA1A, ATP1A2, or SCN1A genes (Evidence: Strong 1).
Preventive Medications: Initiate preventive therapy with beta-blockers, anticonvulsants, or calcium channel blockers based on patient profile (Evidence: Moderate 1).
Caution with Triptans: Exercise caution with triptans due to potential reduced efficacy in trigeminal pathways in FHM1 models (Evidence: Weak 1).References
1 Chan KY, Labastida-Ramírez A, Ramírez-Rosas MB, Labruijere S, Garrelds IM, Danser AH et al.. Trigeminovascular calcitonin gene-related peptide function in Cacna1a R192Q-mutated knock-in mice. Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism 2019. link