Seizures and epilepsy

Añadido: 2026-06-01

[00:00:02]A seizure refers to a one-time event caused by abnormal, excessive, and synchronous electrical activity in the brain that can result in autonomic, sensory, and motor symptoms. When seizures specifically involve motor activity, like jerking, we call them convulsions. Most seizures last less than 5 minutes, but if the seizure continues for more than 5 minutes, it's called status epilepticus.

[00:00:30]Keep in mind that seizures are a symptom, not a diagnosis, meaning they can occur due to various underlying causes, such as trauma, infections, and metabolic imbalances. However, when seizures arise without a clear cause, they are considered unprovoked. And if someone experiences two or more unprovoked seizures at least 24 hours apart, think epilepsy.

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[00:01:12]>> Normally, the brain and its neurons rely on a balance between excitatory and inhibitory neurotransmitters.

[00:01:19]Think of excitatory neurotransmitters like green traffic lights that speed things up, encouraging the neuron to pass electrical impulses to the next one. On the other hand, inhibitory neurotransmitters act like red traffic lights that slow traffic down, stopping the further propagation of electrical impulses.

[00:01:39]Now, whether there's too much excitation or not enough inhibition, neurons can begin firing impulses simultaneously.

[00:01:47]This leads to abnormal, excessive, and synchronous electrical activity in the brain, which results in a seizure.

[00:01:56]Now, there are various causes of seizures, and you can remember the most important ones using the mnemonic vitamins. V stands for vascular conditions like strokes and intracranial hemorrhage, and I covers infection, including meningitis, encephalitis, and brain abscess.

[00:02:15]Next, the first T refers to head trauma, while the second T refers to toxins, such as cocaine or amphetamine overdose, but also alcohol withdrawal.

[00:02:28]A is for autoimmune conditions, such as CNS vasculitis and lupus, and M is for metabolic conditions, including hepatic and uremic encephalopathy, as well as electrolyte disturbances, such as hyponatremia.

[00:02:43]The second I is for idiopathic, meaning no identifiable cause, which refers to epilepsy.

[00:02:49]Finally, N is for neoplasm or brain tumors, and S covers differential diagnoses like syncope, psychogenic seizures, and migraines.

[00:03:01]Now, based on where the abnormal activity starts, seizures are broadly classified into generalized and focal seizures.

[00:03:10]Generalized seizures arise from both cerebral hemispheres and almost always cause a sudden impairment of consciousness.

[00:03:17]This type of seizure can be further subdivided into generalized motor and non-motor seizures.

[00:03:25]Generalized motor seizures, as their name implies, involve muscle activity and include several types. First, tonic seizures are characterized by a significant increase in muscle tone that results in stiffness and rigidity.

[00:03:40]Next, clonic seizures are associated with repeated, rapid, rhythmic jerking movements, usually of arms and legs.

[00:03:49]These episodes can last from several seconds to a couple of minutes.

[00:03:54]Also, there's a combination of the two patterns called tonic-clonic seizures, which combine muscle stiffening with muscle jerking.

[00:04:03]During tonic-clonic seizures, a person may experience a sudden contraction of their vocal cord muscles, resulting in an involuntary scream or cry. Also, the eye muscles can contract, causing the eyes to roll back, while the contraction of the oropharyngeal muscles can impair swallowing, causing saliva to pool in the oropharynx.

[00:04:24]On top of that, the jaw muscles can contract and result in tongue biting.

[00:04:28]In this case, a person might also lose control of their bladder or bowels during a seizure, resulting in urinary and fecal incontinence.

[00:04:39]Next, we have atonic seizures, which basically means seizures with no muscle tone. In this type, there's a sudden loss of postural muscle tone lasting 1 to 2 seconds, causing the individual to collapse to the ground.

[00:04:53]On the flip side, myoclonic seizures involve sudden, brief, rapid muscle twitches that last only a fraction of a second.

[00:05:01]Finally, there's a combination of the previous two called myoclonic-atonic seizure, marked by rapid muscle twitches followed by a brief loss of muscle tone and collapse.

[00:05:13]All right, moving on to generalized non-motor seizures, also known as absence seizures, which are most common in children and adolescents.

[00:05:23]These seizures cause a brief loss of consciousness, particularly awareness, without any change in the postural muscle tone.

[00:05:30]It's like the brain hits the pause button for a moment, then quickly presses play again. For example, a student might be sitting in class, listening to a lecture, and suddenly zone out, only to snap back to reality several moments later.

[00:05:44]Unfortunately, these episodes can occur hundreds of times per day, and parents and teachers often think the child is just staring off into space or not paying attention.

[00:05:56]Furthermore, absence seizures are subdivided into typical and atypical absence seizures.

[00:06:03]Typical absence seizures come on quickly, usually last up to 20 seconds, and have a fast recovery.

[00:06:10]On the other hand, atypical absence seizures are slower in onset, last more than 20 seconds, and take more time to recover from.

[00:06:18]After atypical absence seizures, individuals often appear confused or dazed.

[00:06:25]Now, switching gears to focal seizures, which occur when abnormal activity occurs in a specific part of the brain.

[00:06:32]Depending on the part of the brain that is affected, focal seizures can result in motor, sensory, or autonomic symptoms.

[00:06:41]For example, abnormal activity in the primary motor cortex can cause tonic movements on the opposite side of the body.

[00:06:49]If this activity spreads to neighboring neurons, the jerking can progress to surrounding muscle groups, which is known as the Jacksonian march.

[00:06:59]Next, abnormal activity in the occipital cortex can cause visual symptoms, such as flashing lights. Sometimes, focal seizures may begin as subtle neurological symptoms called auras.

[00:07:11]During an aura, individuals usually show subtle involuntary muscle movements called automatisms, such as lip smacking and blinking of the eyes.

[00:07:21]Auras can also include experiencing unusual odors, like kerosene, a rising sensation in the stomach, or even experiencing fear or deja vu.

[00:07:32]Now, when experiencing a focal seizure, a person can be either aware or unaware of what's happening. In focal seizures with retained awareness, individuals remain alert and awake, so they will know something is going on and remember the seizure afterward.

[00:07:48]On the flip side, during focal seizures with impaired awareness, individuals are not aware of what's happening, so they are often unresponsive during the episode. Because of this, they typically can't recall what was going on.

[00:08:02]Finally, it's important to note that in some cases, abnormal activity can affect a specific part of the brain causing a focal seizure and then spread to both sides of the brain leading to a generalized seizure.

[00:08:17]Now, let's talk about status epilepticus. As mentioned, seizures usually last less than 5 minutes.

[00:08:24]However, if a seizure persists for 5 minutes or more, or if there are multiple seizures without full recovery of consciousness in between, we are talking about status epilepticus.

[00:08:36]Now, there are two types. The first one is convulsive status epilepticus, which typically involves tonic-clonic seizures with jerking movements.

[00:08:45]The second one is non-convulsive status epilepticus, where a person has impaired consciousness but no obvious motor activity. One example of this type is absence status epilepticus, which might look like prolonged staring into space.

[00:09:02]Regardless of the type of seizure, once the episode resolves, individuals can enter a postictal phase, which can last anywhere from several minutes to hours.

[00:09:13]During this time, individuals are typically sluggish, tired, and hard to wake up. Sometimes, if no one witnessed the seizure, the postictal state might be the only clue that a seizure happened because the person likely won't remember it.

[00:09:30]Diagnosis primarily relies on history and physical examination.

[00:09:34]Be sure to ask for factors that can trigger seizures, including physical exhaustion, sleep deprivation, a missed dose of anti-epileptic medications, as well as things like flickering lights from TV or phone screens.

[00:09:48]Next, obtain labs to rule out metabolic causes, as well as a head MRI to check for intracranial conditions, such as bleeding or tumors.

[00:09:59]Once you rule out all potential causes, you can say that your patient is presenting with unprovoked seizures.

[00:10:06]And if someone has two or more unprovoked seizures at least 24 hours apart, think of epilepsy.

[00:10:13]Sometimes you can diagnose epilepsy after just one seizure, but only if there's a high chance that more will occur in the future.

[00:10:20]But to confirm this, the key is electroencephalography, which can help you assess brain activity and identify whether the seizure is focal, generalized, or focal-to-generalized.

[00:10:35]Management of seizures, such as status epilepticus, focuses on stopping the episode quickly, usually with benzodiazepines like lorazepam or midazolam.

[00:10:45]On the other hand, managing epilepsy is a long-term strategy that involves starting anti-epileptic medications like valproate or levetiracetam to prevent future seizures.

[00:10:58]All right, as a quick recap, whether there's too much excitation or not enough inhibition, neurons in the brain can start firing electrical impulses simultaneously, which can lead to seizures. Generalized seizures arise from both cerebral hemispheres and often impair consciousness. Generalized motor seizures include types like tonic, clonic, atonic, and myoclonic seizures.

[00:11:24]While generalized non-motor seizures are also known as absence seizures. On the flip side, focal seizures originate from a specific part of the brain and can be classified based on a person's awareness as focal seizures with retained and impaired awareness.

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