Seizures and Epilepsy Flashcards
1
Q
Define seizure
A
- Sudden paroxysmal excessive discharge of cerebral neurons resulting in transient sensory, motor, cognitive impairment
- Can happen in normal brains or secondary to acute conditions
- Finite event, has a beginning & end
2
Q
Define epilepsy
A
- A chronic neurological disorder, a condition characterized by sudden recurrent episodes of seizures associated with abnormal electrical activity in the brain that manifest as sensory disturbance, motor impairments, loss of consciousness, or convulsions
3
Q
Describe a seizure
A
- Can be induced in any normal brain be a variety of different electrical & chemical stimuli
- Can also occur as a physiological reaction of the brain to physiologic stress, sleep deprivation, fever, alcohol, sedative drug withdrawal
- May occur in many medical illnesses if brain function is temporarily impaired or can occur w/o any discernible reason in otherwise healthy people
4
Q
Describe epilepsy
A
- A syndrome of recurrent seizures & observed by a set of clinical & electroencephalographic (EEG) features
- Many have age of onset
- Responds to particular treatments
- May have specific prognostic outcomes depending on the type of epileptic syndrome
5
Q
What is epilepsy characterized as
A
- Electroclinical syndromes
- Non-syndromic epilepsies
- Epilepsies of unknown cause (idiopathic)
6
Q
Incidence of epilepsy
A
- After headache, epilepsies are the most frequent chronic neurologic condition seen by GP’s worldwide
- Highest incidence among children & elderly and in men slightly more than women
- 3rd most common serious neurologic disease of old age after dementia & stroke
7
Q
Etiology & risk factors of epilepsy
A
- Underlying cause typically unknown
- Causes can be genetic or acquired
- Genetics is believed to be involved in the majority of cases (directly or indirectly)
- Most are due to the interaction of multiple genes along with environmental factors
- Acquired cases occur as a result of brain injury, stroke, brain tumors, infections of the brain, & developmental malformations through a process known as epileptogenesis
8
Q
Common causes of epilepsies in younger people and older people
A
- Genetic, congenital, or developmental conditions are more common causes in younger people
- Brain tumors & strokes are more common causes in older people
9
Q
Genetic causes of epilepsy
A
- Single or combination of genetic defects presumed to be the cause
- Individual defects can have additive effects along with environmental factors to predispose to epilepsy
- Genetic defect may cause inherited biochemical, membrane, or neurotransmitter defects resulting in abnormal excitability in involved circuits or neurons
- Common features: family Hx, onset in childhood/adolescence
10
Q
Acquired causes of epilepsy
A
- Can be linked to a causative factor (seizure is one of the symptoms)
- Symptom can be transient or can persist
- Causes can be structural or metabolic impairments from malformations, lesions or injuries, or chemical insults
- Hormonal changes trigger seizures, increase in estrogen during ovulation/menstruation (can trigger gestational epilepsy)
11
Q
Pre-/Peri-/Post- natal causes of seizures
A
- Eclampsia (gestational hypertensive encephalopathy) canc ause seizures
- May occur within 24-72 hrs during neonatal period, cannot spread to become generalized due to immaturity of hemispheres/corpus callous limiting movement
- Hypoxia-ischemia insult is most common cause of neonatal seizures with convulsion
- Neonatal hypoglycemia
- Hyper/hypocalcemia and hyper/hyponatremia can also cause seizures within a few days after birth
12
Q
Seizures can develop as a result of
A
- All seizure activity is a result of chaotic synchronous electrical discharge in CNS: sudden burst in neural firing
- Overactivation of the NMDA glutamate receptors
- Alterations in neurotransmitter activity in afferents from brainstem to cortex
- Pathologic attempt by the CNS to compensate by sprouting of excitatory mossy fibers
13
Q
Pathogenesis of seizures
A
- Normally spread of neuronal bursting activity is prevented by inhibitory mechanisms (hyperpolarizations of inhibitory interneurons)
- GABA is main inhibitory NT in CNS
- GABA agonists (gabapentin, pregabalin) can stop seizures
- Bursting pattern depends on type of seizure
-Generalized tonic-clonic seizures (grand Mal seizure) have a sustained high frequency discharge, followed by interruptions of continuous firing, followed by restoration of membrane potential
14
Q
Describe focal seizures
A
- Abnormal discharge remain confined to a redistricted area in cortex
- Hippocampal sclerosis (aka medial temporal sclerosis) is characterized by neuronal loss & gliosis (most common cause of focal epilepsy in adolescents & adults)
15
Q
Describe kindling
A
- A neuropathic phenomenon: experimental explanation for seizure activity in epilepsy
- Repeated exposure to low intensity electrical or chemical stimuli results in facilitation/potentiation of connections
- Has been used to induce seizure & epilepsy in animal models
- Can explain onset of epilepsy from initial brain injury
- Can explain how distant areas of brain become susceptible to seizures
- Can explain why surgical ablation of focal areas don’t always stop seizures
- Cannot explain why some epilepsies came to an end even after years of repeated seizures
16
Q
Clinical manifestations of seizures
A
- In most individuals seizures occur unpredictably w/o any warning signs
- In others seizures are provoked by specific stimuli such as flashing light or a flickering television (triggers)
- In some there are some prodromal symptoms (Aruas) that indicate an impending seizure
17
Q
Events that may trigger seizure
A
- Stress
- Poor nutrition
- Missed medication
- Skipping meals
- Flickering lights
- Illness
- Fever and allergies
- Lack of sleep
- Emotions such as anger, worry, fear
- Heat and humidity
18
Q
Clinical manifestations of generalized tonic-clonic seizure
A
- Classic type/grand mal seizure
- Involve both hemispheres
- Loss of consciousness
- Starts with general rigidity, sustained contractions of limb extensors, arching of back lasting 10-30 sec (tonic phase),may hear a cry or see them turn blue (cyanosis)
- Followed by general rapid jerky movements of limbs (clonic phase)
- Followed by recovery period (post-ictal phase), can last minutes to hours, may feel tired/headache/confusion/difficulty speaking, may fall into deep sleep with salivary frothing
- Can cause bowel/bladder incontinence
- Sometimes causes oral trauma, vertebral Fx, shoulder dislocation, aspiration pneumonia, or death
19
Q
Clinical manifestations of absence seizures
A
- Petit mal seizures
-Generalized seizure type - Loss of conscious control, but person is unaware of it
- Sudden cessation of ongoing conscious activity (stares into space)
- Not preceded by aura and immediately followed by return to normal activity
- Occur mostly in children & disappear with adolescence
20
Q
Clinical manifestations of focal/partial seizures
A
- Characterized by locus of onset, neuronal activity restricted to a local structure or with networks limited to one hemisphere
- EEG shows activity in a focal area
- Symptoms will depend on the lobe the focus is present
- Sensory symptoms depend on the sensory area involved in seizure: localized parenthesis, numbness, tingling, vertigo, auditory, or visual hallucinations
- Classified into simply partial and complex partial seizures
21
Q
Symptoms of focal/partial seizures based on lobe affected
A
- Frontal lobe: bizarre movements, thrashing of arms, pelvic thrusting, pedaling or legs
- Temporal lobe: feeling of deja-vu, jamais-vu
- Parietal lobe: numbness or tingling, agnosia, spatial perceptual distortion
- Occipital lobe: visual distortions or hallucinations
22
Q
Clinical manifestations of simple partial seizures
A
- Individual retains consciousness
- Typically last 60-120 secs
- Subjective unusual sensations/feelings: feelings of fear, anger, sadness, happiness or nausea, sensations of falling or movement
- Altered sense of hearing, smelling, tasting, seeing, tactile perception or involuntary movements
- Space or time distortions
- Deja-vu/Jamais-vu
- Labored speech or inability to speak at all
- If somatosensory or motor area involved tingling or clonic jerks can progress or march from distal to proximal parts known as Jacksonian March
- Can occur during sleep, typically REM sleep
23
Q
Clinical manifestations of myoclonic seizures
A
- Sudden brief single or repetitive muscle contractions involving one body part or entire body
- Myoclonic jerks range from small movements of the face and hands to massive bilateral spasms
- Repeated myoclonic jerks may get severe & turn into generalized tonic-clonic seizures with convulsions
- Can happen anytime but often observed shortly after waking up or while falling asleep
24
Q
Clinical manifestations of dyscognitive seizures
A
- Complex partial seizure
- Loss of consciousness or impairment of awareness or responsiveness
- Often preceded by aura
- Once consciousness lost may show automatisms like lip smacking, chewing, swallowing
- Most commonly arise in medial temporal lobe & consciousness is lost when discharge spreads to hippocampus & amygdala
- May show amnesia about the details surrounding the seizure event
25
Q
Clinical manifestations of atonic seizures
A
- AKA drop attacks
- Brief loss of consciousness & postural control
- Most often in children
- Characterized by sudden loss of muscle tone that may result in falls with injury
- Sometimes loss of muscle tone happens in neck muscles causing head drop
26
Q
Clinical manifestations of status epilepticus
A
- When person has generalized tonic-clonic seizures that are so long or so repeated that there is nor recovery or return of consciousness
- Medical emergency, can cause death
- Often occurs due to tumor, CNS infection, or drug abuse
- Febrile seizures in children under 3 yrs are also a common cause
27
Q
Describe electroclinical diagnosis of seizures
A
- Electroencephalography (EEG): central role, inter-octal activity provides strong evidence that the event was a seizure
- Best way to diagnose & classify seizure event: observe patient & EEG
- Normal reading does not rule out seizure event
- Other indicators: age of onset, status of client after the episode, responses to medications
28
Q
Describe magnetocephalography diagnosis of seizures
A
- Differential diagnosis
- Loss of postural control/consciousness due to seizure versus syncope, OH, cariogenic arrhythmia, sometimes may be difficult to distinguish
29
Q
Describe the treatment for seizures
A
- Control of seizure is most important
- Antiepileptic drugs can be used depending on the type of seizure
- Commonly used drugs: Carbamazepine, Levetiracetam, Phenytoin, Pregabalin, Gabapentin
- Antiepileptic drugs have adverse side effects: dizziness, diplopia, blurred vision, ataxia, hepatic failure, anemia, lupus like syndrome, Steven-Johnson syndrome
- Ketogenic diet (high fats) helpful in reducing convulsions
- Surgical treatment like lobectomies, sectioning of corpus callous indicated if drug therapy does not control seizures
- Vagus nerve stimulation found to reduce seizures by 50%
30
Q
Pharmacologic effects of different anti epileptic drugs in modulating GABA activity
A
- Act by either by mimicking GABA neurotransmitter or by inhibiting metabolic breakdown of GABA or preventing re-uptake
31
Q
Describe the prognosis of epilepsy
A
- Those with epilepsy have increased mortality rates
- Death can happen from asphyxia (when seizure occurs during eating), drowning, or sudden unexplained death
- For children diagnosed of unknown cause, remission is defined as 5 yrs w/o seizures
- 75% remission rate for those diagnosed before 10 yrs
- Children seizure free for more than 4 yrs while taking anti epileptic drugs have 70% chance of permeant remission when drugs are withdrawn
- If period of uncontrolled seizures extend to 4yrs, the chances of ever achieving control is 10%
32
Q
Implications for the therapist
A
- Understanding the facts about the type of epilepsy
- Seizure event recognition
- Patient needs protection from injury during seizure not restraint
- Make sure patient is lying on a surface to prevent falls
- Rolling the patient to sidelying position may help airway to keep clear
- Observation/documentation of physical symptoms, duration of seizure, cognitive status
- Knowledge of triggers
- Evaluation of home, school environments for safety recommendations
- Patients can be encouraged to participate in activities with adequate supervision provided seizures are controlled by medications
-Adequate knowledge of medication side effects
