Seizures and Epilepsy

Question 1

Define seizure

Answer 1

• 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

Question 2

Define epilepsy

Answer 2

• 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

Question 3

Describe a seizure

Answer 3

• 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

Question 4

Describe epilepsy

Answer 4

• 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

Question 5

What is epilepsy characterized as

Answer 5

• Electroclinical syndromes
• Non-syndromic epilepsies
• Epilepsies of unknown cause (idiopathic)

Question 6

Incidence of epilepsy

Answer 6

• 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

Question 7

Etiology & risk factors of epilepsy

Answer 7

• 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

Question 8

Common causes of epilepsies in younger people and older people

Answer 8

• Genetic, congenital, or developmental conditions are more common causes in younger people
• Brain tumors & strokes are more common causes in older people

Question 9

Genetic causes of epilepsy

Answer 9

• 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

Question 10

Acquired causes of epilepsy

Answer 10

• 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)

Question 11

Pre-/Peri-/Post- natal causes of seizures

Answer 11

• 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

Question 12

Seizures can develop as a result of

Answer 12

• 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

Question 13

Pathogenesis of seizures

Answer 13

• 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

Question 14

Describe focal seizures

Answer 14

• 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)

Question 15

Describe kindling

Answer 15

• 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

Question 16

Clinical manifestations of seizures

Answer 16

• 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

Question 17

Events that may trigger seizure

Answer 17

• 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

Question 18

Clinical manifestations of generalized tonic-clonic seizure

Answer 18

• 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

Question 19

Clinical manifestations of absence seizures

Answer 19

• 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

Question 20

Clinical manifestations of focal/partial seizures

Answer 20

• 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

Question 21

Symptoms of focal/partial seizures based on lobe affected

Answer 21

• 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

Question 22

Clinical manifestations of simple partial seizures

Answer 22

• 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

Question 23

Clinical manifestations of myoclonic seizures

Answer 23

• 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

Question 24

Clinical manifestations of dyscognitive seizures

Answer 24

• 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

Question 25

Clinical manifestations of atonic seizures

Answer 25

- 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

Question 26

Clinical manifestations of status epilepticus

Answer 26

- 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

Question 27

Describe electroclinical diagnosis of seizures

Answer 27

- 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

Question 28

Describe magnetocephalography diagnosis of seizures

Answer 28

- Differential diagnosis - Loss of postural control/consciousness due to seizure versus syncope, OH, cariogenic arrhythmia, sometimes may be difficult to distinguish

Question 29

Describe the treatment for seizures

Answer 29

- 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%

Question 30

Pharmacologic effects of different anti epileptic drugs in modulating GABA activity

Answer 30

- Act by either by mimicking GABA neurotransmitter or by inhibiting metabolic breakdown of GABA or preventing re-uptake

Question 31

Describe the prognosis of epilepsy

Answer 31

- 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%

Question 32

Implications for the therapist

Answer 32

- 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