Epilepsy (generalized, focal) – tonic-clonic, tonic, clonic, causes, symptoms
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Epilepsy (generalized, focal) – tonic-clonic, tonic, clonic, causes, symptoms

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of pharmacology and clinical reasoning topics. Try it free today. Epilepsy means “seizure disorder”, so
people with epilepsy have recurring and unpredictable seizures. A seizure is a period where cells in the brain,
or neurons, are synchronously active, or active at the same time, when they’re not supposed
to be. Now when I say that neurons are “active”,
I mean that they’re firing or sending a message using electrical signals relayed from
neuron to neuron. And if you look at a neuron under a microscope,
each electrical signal that passes through it is really just ions flowing in and out
of it through protein channels. The way this ion flow is controlled is through
neurotransmitters, a type of signaling molecule, and receptors. Neurotransmitters bind to the receptors and
basically tell the cell to either open up the ion channels and relay the electrical
message, called excitatory neurotransmitters, or close the ion channels and stop the electrical
message, called inhibitory neurotransmitters. During a seizure, clusters of neurons in the
brain become temporarily impaired and start sending out a ton of excitatory signals, over
and over again, and these are sometimes said to be paroxysmal. These paroxysmal electrical discharges are
thought to happen due to either too much excitation, or too little inhibition (which are kinda
two sides of the same coin, right?). The main excitatory neurotransmitter in the
brain is glutamate, and NMDA is the primary receptor that responds to glutamate by opening
ion channels that let calcium in, a positive ion that tells the cell to send signals. Some patients with epilepsy seem to have fast
or long-lasting activation of these receptors. On the flip side, the main inhibitory neurotransmitter
in the brain is GABA, which binds to GABA receptors that tell the cell to inhibit the
signal by opening channels that let in chloride ions, which are negative ions that tell the
cell to inhibit signals. Some patients with epilepsy seem to have genetic
mutations in which their GABA receptors are dysfunctional, and so they aren’t able to
help inhibit signals. In addition to potentially having a primary
genetic cause, though, these receptors and ion channels might be affected by all sorts
of things like brain tumors, brain injury, or infection. Whether it’s a decrease in inhibition or
an increase in activation, when groups of neurons start firing simultaneously, over
and over, it’s often noticed by others as obvious outward signs, like jerking, moving,
and losing consciousness, but can also be subjective experiences that are only noticed
by the person experiencing it, like fears or strange smells, it all depends on which
neurons in the brain are affected. People with epilepsy experience recurring
episodes of some form of seizures, and we can start grouping the seizures by the region
of the brain that’s affected. When the affected area is limited to one hemisphere
– or one half of the brain – or sometimes even a smaller area like a single lobe, we
call it a focal seizure (though it used to be called a partial seizure). These seizures are subcategorized as either
without impaired awareness or with impaired awareness.. Those without impaired awareness typically
affect a small area of the brain, and can involve the person experiencing strange sensations,
like hearing or tasting something, but can also involve jerking movements in specific
muscle groups if the neurons controlling those muscles are affected. If the jerking activity starts in a specific
muscle group, and spreads to surrounding muscle groups as more neurons are affected, it’s
referred to as a Jacksonian march. Typically, the person is awake and alert and
will usually know that something is happening and will remember the seizure afterwards. Focal seizures with impaired awarenss, on
the other hand, involve having some sort of loss of awareness and responsiveness, so they
might not remember exactly what happened during a seizure. Now, in contrast to the focal seizure, a generalized
seizure is where both hemispheres of the brain are affected. Sometimes, a seizure will start out as a focal
seizure and then quickly develop into a generalized seizure, and in those situations it’s called
focal onset bilateral tonic-clonic because a focal seizure came before it and was the
primary event. Just like focal seizures, there are some subcategories
of generalized seizures as well. One subtype is a tonic seizure, where the
muscles all the sudden become stiff and flexed, which can cause the patient to fall, often
backwards. On the flipside, they can be atonic as well,
where their muscles suddenly relax and become floppy, which again can cause the patient
to fall, but this time forward. Seizures can also be clonic, where they have
violent muscle contractions, also known as convulsions. Tonic-clonic seizures are the most common
generalized seizures, where patients experience a tonic phase where the muscles suddenly tense
up, followed by the clonic phase, where muscles rapidly contract and relax. Myoclonic seizures are yet another type, and
are short muscle twitches, sometimes just a single twitch but sometimes many in a short
amount of time. Finally there are absence seizures, where
patients have some sort of impaired awareness or responsiveness, generally with the only
outward sign being that the person looks like they spaced out, like if they were walking,
they’ll suddenly stand still. The key for all of these is that they all
involve both hemispheres of the brain. If the seizures themselves last for a longer
period of time (like over 5 minutes of ongoing seizures or having multiple seizures without
returning to normal in between), then it’s called status epilepticus. These are usually of the tonic-clonic subtype
of seizures, but it can also be caused by the other types that don’t involve convulsions. This situation is considered a medical emergency
and can be life-threatening if not treated immediately. Due to the severity of these seizures, patients
are often treated acutely with benzodiazepines, which help enhance the effect of the inhibitory
neurotransmitter GABA. Following a seizure, sometimes patients can
experience symptoms following a seizure, like confusion, called “post-ictal” confusion,
which means “after seizure” confusion. Also, patients might experience paralysis
that affects the arms or the legs, usually just limited to one side of the body. And this is known as Todd’s paralysis or
Todd’s paresis, and can last for quite a while – on average about 15 hours; and usually
it subsides by itself completely after 2 days. The precise mechanism behind Todd’s paralysis
isn’t currently well understood, but it’s thought to be the result of temporary but
severe suppression of activity of the area in the brain affected by the seizure. Typically, after a seizure is over, patients
will have brain imaging techniques like MRI or CT scans, as well as an EEG, or electroencephalogram,
which detects electrical activity in the brain. With patients who’ve just started having
seizures, brain scans are used to find out if there’re any anatomical abnormalities,
like brain tumors or abnormal blood vessels that could be causing the seizures, both of
which would be treated surgically. Because epilepsy can vary from patient to
patient in the type, severity, and frequency of seizures, diagnosis typically involves
a variety of examinations and tests in combination with a thorough evaluation of their clinical
history. Once epilepsy’s been diagnosed, it’s often
treated with daily medication, the primary form of medication being anticonvulsants,
of which there are a wide variety of options available that have different targets in the
brain, so the choice is based on the specific needs of the patient, including factors like
age, lifestyle, other health problems, and the category or subcategory of the epilepsy
syndrome. Other treatment options include epilepsy surgery,
where they’ll remove what’s thought to be causing the seizures, like a specific part
of the brain or a tumor. Nerve stimulation might also be considered,
where certain nerves like the vagus nerve are stimulated, which is thought to control
seizures by influencing neurotransmitter release. Also, patients might adopt a ketogenic diet,
which is a diet that forces the body to burn fat instead of carbohydrates, which produces
ketone bodies which are used by the brain as an energy source instead of glucose—although
many hypotheses have been suggested for why this seems to reduce seizures for some patients,
the exact mechanism isn’t very well understood. All right, as a quick recap, epilepsy is a
disorder where somebody experiences recurring seizures, where neurons fire over and over
again. Focal seizures typically only affect one localized
area of the brain—like one hemisphere, and can be split into those with impaired awareness
and without impaired awareness. Generalized seizures involve both hemispheres,
and there are a bunch of subtypes, though the most common are tonic-clonic seizures.

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78 thoughts on “Epilepsy (generalized, focal) – tonic-clonic, tonic, clonic, causes, symptoms

  1. I have absence and myoclonic seizures. I'm so glad I don't have tonic clonic seizures, my form of epilepsy is nothing tbh.

  2. Very useful concise presentation!
    Would it be correct here to add the inhibitory effect of post-synaptic signaling from second neuron with endocannabinoid neurotransmitter to pre-synaptic neuron (most likely modulating Ca/Mg channels)? Which is the target of CBD treatments.

  3. Harrison distinguishes Epilepsy from Seizures. Also, it claims the terminology of Partial is non existent nowadays. BTW, great video. Thanks Guys.

  4. I'm epletic and other children in my class take the mick out of my staring seizures.And they say my seizures are fake.But i mandge it

  5. I have it I have to have seizures every time I'm hot I can't stop it
    Who else has this and is it hot when you have one?

  6. My grandmother has epilepsy. She was born in 1944 and had a fever when she was around 3 years old. That's what gave her epilepsy in the first place. There where no school buses and no medicine to help children like that. She tells stories of how she would wake up in the nurses office and not remember how she got there because she blacks out when she had them. She's still alive now and thanks to the medicine she doesn't suffer from then anymore however without it she could have one again and possibly die.

  7. My friend and my dad have epilepsy i dont know what type my dad has but my friend has tonic clonic we dont know if i have it im getting my brain tested soon because my school is saying ill be doing anything and stop for a few mins 😂 im scared

  8. I was born with epilepsy and cerebral palsy. I have a twin brother, i was born first. My brother was born with no problems. I take phenytoin for my epilepsy, as a child I was on phenabarbatone, then at 14 i was put on Epilim 500mg. Which caused me to gain lots of weight. I went to live in canada for a few years where I was taken off eperlim & switched to phenytoin. Which I still take today. As a child I had grand mal seizures, which doctors said I would grow out of. Which I did, but I now have petit mal. It' feels weird when I have it, i can hear all thats going on around me, but ppl and any noise, sound much louder, plus it feels like I'm floatong on water. Before the seizure I get the smell like burnt toast. I can have a seizure at any time, night or day. Unpredictable. I feel a little confused when I come round, which lasts for a couple of minutes, then I'm back with you again. Usually a cup of tea helps me recover.

  9. I have a vns implanted in my body from surgery it is working fine now and very well I getting back into energy and back to life again. I am glad I have a vns inside me I still get fits but I don't know when they come because of the type of epilepsy 6 have complex partial I was very young when I got it.

  10. It’s horrible having epilepsy!

    I don’t have epilepsy, but my auntie does. I have viewed two of her hundreds of seizures in her life, and it’s a scary experience! It’s the worst thing you could ever wish on someone.

  11. Your classifications are flawed. General epileptic seizure its classified as(a) petit mal …absence(b) Grand mal …Big seizures

  12. I have simple partial seizures with Todd’s Paresis the seizures are under control with medication but I still suffer from the Todd’s Paresis … what an insightful video

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