Seizure (fit or convulsion): causes, red flags and when to seek help

The popular image is of a person collapsing and shaking, but that describes only one type. The NHS lists the possible signs: the body becoming stiff or floppy, suddenly falling to the floor, jerking or twitching movements, peeing unintentionally, losing awareness of what is around you (staring into space and not responding normally), unusual feelings such as strange smells, numbness, tingling, visual changes or suddenly feeling scared, and unusual behaviour such as fidgeting or walking around unaware of what you are doing.

The NHS names the main types of epileptic seizure as tonic-clonic, where you become unconscious and may fall, the muscles stiffen and the body jerks and shakes, tonic, where muscles suddenly stiffen, atonic, where they go floppy, absence, a brief loss of awareness, focal, with unusual sensations or movements, and myoclonic, brief muscle jerks. You may or may not remember the seizure afterwards.

The NHS describes epilepsy as a condition that affects the brain and causes seizures, with symptoms often starting in young children and people over 50, though it can happen at any age. But it stresses that having a seizure does not always mean epilepsy, since seizures can have other causes.

Seizure-like events with a clear trigger are called provoked. Common triggers include very low blood sugar, alcohol withdrawal or heavy drinking, recreational drugs, some medicines, severe infection of the brain or its lining, head injury, stroke, a brain tumour, low sodium or calcium, kidney or liver failure and lack of sleep. Not every collapse with jerking is a seizure: fainting can cause brief jerks, and non-epileptic attacks linked to stress or trauma look similar.

The NHS says to call 999 if you think someone is having a seizure and it is the first time it has happened, it lasts longer than is usual for them or longer than 5 minutes if you do not know how long their seizures usually last, they do not recover as usual afterwards or have another seizure without recovering between seizures, or they have now had 3 or more seizures in 24 hours. It notes that people with epilepsy do not always need to go to hospital, since they usually have a care plan saying what to do.

The NHS says to ask for an urgent GP appointment or get help from NHS 111 if you think you or your child may have had a seizure for the first time and did not go to hospital, or if you have had a seizure after having no seizures for a long time.

It also describes status epilepticus, a seizure lasting a long time or several without recovery between, as needing urgent treatment to prevent brain damage. A seizure with a stiff neck, high temperature or rash, after a head injury, during pregnancy, in a person with diabetes, or with a severe headache or new weakness suggests a serious underlying cause and also needs emergency care. For children, the NHS febrile seizure page says to call 999 or go to A&E for a first seizure, one that lasts more than 5 minutes, difficulty breathing, stiffness and twitching on only 1 side, being more sleepy than usual for more than 1 hour afterwards, or more than 1 seizure within 24 hours.

The NHS febrile seizure guidance for children is a good template for anyone: check the time the seizure starts and ends, protect the head with your hands or something soft, remove any dangerous objects nearby, and once it ends, put the person in the recovery position and make sure nothing in the mouth or throat affects breathing. It says not to move the person or hold them in place and not to put anything in their mouth.

Stay with the person until they are fully alert, speak calmly and tell them where they are. Loosen tight clothing around the neck. Do not give food or drink until they have fully recovered. Call 999 using the criteria above, and tell the call handler the time the seizure began.

The NHS says that if you or your child have had a seizure you will need to see a specialist doctor, who will check what caused it and whether you might have epilepsy and ask what happened before, during and after the seizure. It suggests bringing anyone who saw the seizure, since witness accounts are often the most useful part of the assessment. A phone video, if safe to record, helps too.

Tests may include an electroencephalogram (EEG) to check electrical activity in the brain, an ECG to check the heart, an MRI or CT scan, blood tests and genetic testing. You will usually be diagnosed with epilepsy if you have had more than 1 seizure or tests show a risk of having more. The NHS says treatment can often help manage epilepsy, that for most people medicines work well, and that seizures are not usually harmful though they can cause accidents or injuries.

The NHS advises keeping a diary to identify triggers such as tiredness, stress, periods, flashing lights, food or drink, making sure family and friends know what to do, carrying medical ID, making the home safer, having showers rather than baths where possible, thinking about safety when cooking, using tools or machinery, swimming or sports, not missing medicine doses, not changing treatment without advice and not drinking too much alcohol.

It says that if you have had any type of seizure you must not drive and you must tell the DVLA, and when you can drive again depends on the type of seizure and when it last happened.