Summary about Disease
Familial hemiplegic migraine (FHM) is a rare type of migraine with aura that involves motor weakness (hemiplegia). It's a genetic disorder, meaning it runs in families. Episodes typically involve a severe headache, visual disturbances, sensory changes, and weakness on one side of the body. The severity and presentation can vary significantly between individuals and even between attacks within the same individual.
Symptoms
Headache: Typically severe, throbbing, and on one side of the head.
Aura: Visual disturbances are common (flashing lights, blind spots), sensory changes (numbness, tingling), speech difficulties, and motor weakness (hemiplegia) affecting one side of the body.
Other neurological symptoms: Confusion, drowsiness, difficulty concentrating, seizures, loss of consciousness.
Gastrointestinal symptoms: Nausea, vomiting.
Causes
FHM is caused by mutations in specific genes that affect the function of ion channels in the brain. The most commonly affected genes are:
CACNA1A: Encodes a subunit of a calcium channel.
ATP1A2: Encodes a subunit of a sodium-potassium pump.
SCN1A: Encodes a sodium channel. These mutations disrupt neuronal excitability and can lead to the migraine aura and associated symptoms. It is inherited in an autosomal dominant pattern.
Medicine Used
Acute Treatment:
Triptans: (e.g., sumatriptan, rizatriptan) - Used to treat the headache phase, but caution is advised due to the hemiplegia. Some sources suggest avoiding triptans in FHM. Consult a neurologist specializing in headaches.
NSAIDs: (e.g., ibuprofen, naproxen) - For pain relief.
Anti-emetics: (e.g., metoclopramide, prochlorperazine) - For nausea and vomiting.
Acetaminophen: For pain relief.
Preventive Treatment:
Calcium channel blockers: (e.g., verapamil)
Beta-blockers: (e.g., propranolol)
Antidepressants: (e.g., amitriptyline)
Anticonvulsants: (e.g., topiramate, valproate)
CGRP monoclonal antibodies: (e.g., erenumab, fremanezumab, galcanezumab) - Newer medications, used for migraine prevention.
Botulinum toxin (Botox): For chronic migraine prevention.
Is Communicable
No, FHM is not communicable. It is a genetic disorder passed down through families.
Precautions
Genetic Counseling: If you have a family history of FHM, consider genetic counseling to assess your risk and the risk for your children.
Avoid Triggers: Identify and avoid potential migraine triggers, such as stress, certain foods (aged cheeses, processed meats, alcohol), caffeine withdrawal, and changes in sleep patterns.
Regular Sleep Schedule: Maintain a consistent sleep schedule.
Manage Stress: Practice stress-reducing techniques, such as yoga, meditation, or deep breathing exercises.
Hydration: Stay well-hydrated.
Medical Alert: Wear a medical alert bracelet or carry a card indicating that you have FHM and any relevant medical information.
Inform Healthcare Providers: Make sure all your healthcare providers are aware of your FHM diagnosis.
How long does an outbreak last?
The duration of an FHM attack can vary. Symptoms can last from a few hours to several days (typically 24-72 hours). The hemiplegia may sometimes last longer than the headache.
How is it diagnosed?
Clinical Evaluation: A thorough medical history, including family history of migraine with aura and hemiplegia, is crucial.
Neurological Examination: To assess motor strength, sensation, reflexes, and coordination.
Brain Imaging: MRI or CT scan of the brain may be performed to rule out other causes of the symptoms.
Genetic Testing: Genetic testing can confirm the diagnosis by identifying mutations in the known FHM genes (CACNA1A, ATP1A2, SCN1A).
Diagnostic Criteria: Diagnosis is based on the International Headache Society (IHS) criteria for hemiplegic migraine.
Timeline of Symptoms
The timeline of symptoms can vary, but a typical FHM attack may unfold as follows: 1. Prodrome (Hours to Days Before): Some individuals experience premonitory symptoms such as mood changes, fatigue, or food cravings. 2. Aura (5-60 minutes): Visual disturbances, sensory changes (numbness, tingling), speech difficulties, and motor weakness (hemiplegia). Aura symptoms typically develop gradually. 3. Headache (4-72 hours): Severe, throbbing headache, usually on one side of the head. 4. Postdrome (Up to Several Days): Fatigue, difficulty concentrating, and lingering neurological symptoms.
Important Considerations
Differential Diagnosis: It's important to rule out other conditions that can cause similar symptoms, such as stroke, TIA (transient ischemic attack), seizures, and other neurological disorders.
Stroke Risk: There is some evidence suggesting a potential increased risk of stroke in individuals with FHM, although the absolute risk is still low.
Complications: In rare cases, FHM can be associated with serious complications such as prolonged coma or cerebellar atrophy.
Individualized Treatment: Treatment should be tailored to the individual patient's symptoms and response to medications.
Expert Consultation: Management of FHM should be guided by a neurologist with expertise in headache disorders.