Hemiplegic migraine: symptoms, causes and treatment

The Migraine Trust says a person with hemiplegic migraine will experience temporary weakness on one side of their body as part of their migraine attack. The weakness may be in addition to some more common aura symptoms.

• Visual disturbances in both eyes, such as coloured spots, zig-zags or sparkles.

• Speech difficulties, such as slurring words or not being able to speak clearly.

• Communication difficulties, affecting reading, listening, speaking and writing.

• Dizziness or vertigo, hearing problems or ringing in the ears, and confusion.

• A headache that may follow the weakness, may occur before it, or may not occur at all.

The Migraine Trust says the symptoms can be a frightening experience because they are similar to those of a stroke. The NHS says to call 999 if you or your child cannot move or have weakness in the arms or legs on 1 side of the body, or 1 side of the face, along with other emergency signs.

The NHS migraine page also lists these reasons to call 999 and not to drive yourself to A&E:

• A headache that came on suddenly and is extremely painful.

• Problems speaking or remembering things.

• Losing your vision, or having blurred or double vision.

• Feeling drowsy or confused.

• Having a seizure or fit.

• A very high temperature with symptoms of meningitis.

• A recent head injury.

The NHS says to ask for an urgent GP appointment or get help from NHS 111 if you have a migraine attack and it has lasted longer than 72 hours, aura symptoms last longer than 1 hour at a time, or you are pregnant or have just had a baby. It says to see a GP if your attacks are severe or getting worse, or you have attacks more than once a week.

Note that in hemiplegic migraine the weakness itself can last from an hour to days. That is why the Migraine Trust says it is important that a diagnosis is made and that you discuss a plan with a specialist, rather than assuming weakness is always migraine.

The Migraine Trust describes two types.

The Migraine Trust says three gene mutations have been identified in hemiplegic migraine: CACNA1A, ATP1A2 and SCN1A. They cause a related calcium channel in nerve cells to work incorrectly from time to time, which results in an attack. These specific mutations are not present in all families diagnosed with familial hemiplegic migraine.

It explains that the brain depends on electrical and chemical signals, and when a channel in the brain is not working properly, neurotransmitters such as serotonin may be released in an abnormal way. For migraine in general, the NHS says the cause is not known but it happens when there are changes to nerves and blood vessels in the brain, and you are more likely to get it if a close family member has it.

The Migraine Trust says that if you have symptoms of either type, it is important that a diagnosis is made. You may need specialist medical advice to explain the sudden onset of one-sided weakness or numbness. The diagnosis must always be based on a thorough evaluation of your symptoms and include a full family history.

The Migraine Trust says that if you have suspected hemiplegic migraine, specialist advice is recommended so that you are given the most appropriate treatments. Triptans, for example, are best avoided during the aura phase and a specialist should assess whether it is safe to use them during the headache phase.

As with other types of migraine, there is not a single best treatment. The Migraine Trust says a specialist considers your medical history and symptoms and may recommend preventive treatments such as flunarizine (limited access in the UK), topiramate or others.

For migraine in general, the NHS says treatments for an attack include painkillers such as ibuprofen and paracetamol, triptans and gepants, and medicines that stop you feeling sick. It says to try not to take painkillers for more than 2 days a week, as this can cause more headaches. The suitability of these for hemiplegic migraine is a question for a specialist.

The NHS suggests these steps for migraine in general, with help and advice from a GP: try to avoid things you know trigger your attacks, stay well hydrated and limit caffeine and alcohol, eat meals at regular times, keep to a healthy weight, get regular exercise and plenty of sleep, and try to manage stress. A migraine diary can help work out what might trigger attacks. The pages used here do not name a specific diet for hemiplegic migraine.

On the NHS, an acute episode of one-sided weakness is an emergency assessed through 999 and A&E, where stroke and other causes are excluded. Ongoing care is usually through your GP and a neurology or headache service.

Private neurology is also available for diagnosis and preventive treatment planning. Ask for a clear written plan covering which medicines to avoid, what to do during an attack, and when to call 999.