Epilepsy Flashcards
What is a seizure?
- Hypersynchronous continuous discharge of cortical neurons without inhibition
- It’s a symptom, not a disease
- Only from cortex (not from brainstem, basal ganglia, etc.)
Symptoms of a seizure?
- Loss of consciousness
- Loss of awareness
- Uncontrollable movements
- Unusual behaviors or sensations
What is epilepsy?
- Recurrent spontaneous seizures
- At least two unprovoked seizures occurring more than 24 hours apart
Note: a single unprovoked seizure has a high recurrence (i.e., >60% over the next 10 years)
Clinical manifestations of epilepsy?
- range from a major motor convulsion to a brief period of lack of awareness.
- The stereotyped and uncontrollable nature of the attacks is characteristic of epilepsy
When is epilepsy considered resolved?
for people who have been seizure-free for the past 10 years with no medication for the past 5 years
Prevalence of epilepsy in Malawi?
Malawi - 2.8% prevalence rate overall.
Epidemiology and course of epilepsy?
Epilepsy usually presents in childhood or adolescence but may occur for the first time at any age
1. newborns
2. early school age
3. adolescents
4. seniors
Pathogenesis of epilepsy?
- EXCESSIVE NEURONAL EXCITABILITY
- (no balance) and a pattern of synaptic connections between neurons that permits hypersynchrony - CELLULAR PROCESSES
- altered activity of voltage gated ion channels which affects resting potential and electrical excitability - EXCITATORY NEUROTRANSMITER glutamate (increased in epilepsy) and inhibitory gamma aminobutyric acid (GABA) (decreased)
Categories of epilepsy seizure syndromes?
- generalized seizures
- focal/partial seizures
Describe generalized epilepsy?
the predominant type of seizures begins simultaneously in both cerebral hemispheres
- subcortical in origin
Note: Many forms of generalized epilepsy have a strong genetic component; in most, neurologic function is normal
Describe focal epilepsy?
seizures originate in one or more localized foci, although they can spread to involve the entire brain
- cortical in origin
Note: believed to be the result of one or more central nervous system insults, but in many cases the nature of the insult is never identified
Epilepsy classification?
- focal seizures
- generalized seizures
- unclassified seizures
Triad of focal/partial seizures?
- Preceding aura
- Always stereotype - complex series of automatism
- Confusion post ictally
- With secondary generalization
What are Automatisms?
arenon-purposeful, stereotyped, and repetitive behaviors that commonly accompany focal impaired awareness seizures
Focal seizures evolve to what kind of convulsions?
tonic/clonic convulsions
- muscle stiffening and jerking sudden LOC and loss of bladder control
Seizures evolving from the frontal lobe result in what kind physical actions?
- thrashing of the arms
- losing control of the bladder or bowels
Seizures evolving from the parietal lobe result in what kind of physical actions?
tingling/warm feeling down one side
Seizures evolving from the occipital lobe results in?
flashes of light, brief loss of vision
Seizures evolving from the temporal lobe results in?
- plucking at clothes
- smacking lips
What are the types of generalized seizures?
- Absence
- Myoclonic seizures
- Tonic-Clonic seizures
- Tonic seizures
- Clonic seizures
- Atonic seizures
Abscence seizure?
a type of seizure that involves brief, sudden lapses in attention
Myoclonic seizures?
sudden brief jerks or twitches of muscles, as if shocked by electricity with no change in your level of awareness or consciousness
Tonic-clonic seizures?
muscle stiffening and jerking sudden LOC and loss of bladder control
Tonic seizures?
muscle stiffening or increased muscle tone, fall backwards
Clonic seizures?
rhythmic jerking muscle movements, muscles of neck face, arm, legs
Atonic seizures?
drop attacks, sudden loss of muscle tone, drop down
Describe features of grand mal/tonic clonic generalized seizures?
- Abrupt loss of consciousness or bladder control
- All muscles go into spasm (tonic)
- Tonically contracting muscles (tonic)
- Extensors stronger than flexors (tonic) - Periodic release of contraction causes ‘jerks’ /clonus (clonic)
- Continuous for 1-2min with post ictal confusion following
Describe features of generalized absence petit mal seizures?
- Interruption of stream of consciousness and Very brief Loss of awareness
- No loss of tone
- Few seconds at a time
- Children most affected
- Blank stare with or without sudden bodily movement (lip smacking or eye blinking)
- Not aware they have it for years
Febrile seizures?
seizure in children between 6 months and 5 years when they have a temperature of >38 degrees
2 types of febrile seizures?
- simple generalized
- <15 minutes
- 1 seizure in 24 hours - complex focal
- >15 minutes
- > 1 seizure in 24 hours
Vascular causes of seizures?
- hemorrhagic - more epileptogenic
- ischemic - most common
- venous system
- cerebral venous sinus thrombosis, venous infarction - malformations
- arteriovenous malformation, cavernoma - hypoxic-ischemic
- perinatal asphyxia, anoxic encephalopathy e.g. cardiac arrest - dysregulation
- eclampsia, HTN encephalopathy, cerebral vasospasm - stroke syndromes
- moyamoya, lupus vasculopathy, sickle cell, vasculitis
CNS Infectious that cause seizures?
- viral encephalitis
- HSV-1, HIV (opportunistic infections), measles - bacterial meningitis
- granulomatous: TB, syphilis
- pyogenic meningoccoccus, pneumococcus, H. influenzae B - parasitic meningitis
- neurocysticercosis, malaria, toxoplasmosis, toxocariasis, schistosomiasis - fungal meningitis
Systemic infections that cause seizures?
1.urinary tract infections
2. pneumonia
Traumatic causes of seizures?
Encephalomalacia
- isthe softening or loss of brain tissue after cerebral infarction, cerebral ischemia, infection, craniocerebral trauma, or other injury.
Autoimmune causes of seizures?
- Rasmussen encephalitis
- anti-NMDA R encephalitis
Metabolic causes of seizures?
- hyper/hypoglycemia
- hyponatremia <120
Iatrogenic/illicit + alcohol causes of seizures?
- antidepressants - buproprion, venlafaxine
- analgesics - tramadol, meperidine
- antibiotics - carbapenems, isoniazid, fluoroquinolones
- miscellaneous - amphetamines, cyclosporine, theophylline
- withdrawal - benzodiazepines, baclofen, alcohol
Neoplasms that cause seizures?
- gliomas - more epilptogenic
- brain METs
- meningiomas
- most common
Social causes of seizures?
- medication non-compliance
- alcohol withdrawal
- sleep deprivation
- emotional/physical stress
Congenital causes of seuzures?
- vascular and traumatic - hypoxic ischemic encephalopathy
- infections - TORCH infections
- metabolic - inborn errors of metabolism
- malformations - CNS malformations
Degenerative causes of seizures?
Alzheimers disease
Epilepsy differential diagnosis?
- Syncope attacks
- when pt. is standing; results from global reduction of cerebral blood flow; prodromal pallor, nausea, sweating; jerks - Cardiac arrythmias (e.g. Adams-Stokes attacks)
- Prolonged arrest of cardiac rate will progressively lead to loss of consciousness – jerks! - Migraine
- Basilar migraine may lead to loss of consciousness! - Hypoglycemia
– seizures or intermittent behavioral disturbances may occur. - Narcolepsy
– inappropriate sudden sleep episodes - Panic attacks
- PSEUDOSEIZURES
– psychosomatic and personality disorders
Routine and neuroimaging investigations?
- Haematology
- biochemistry (electrolytes, urea ,LFTs, glucose and calcium, magnesium)
- CSF if indicated, level of anticonvulsant drugs
Neuroimaging investigation?
CT/MRI
- should be performed in all persons aged 25 or more presenting with first seizure and in those pts with focal epilepsy irrespective of age
Specialized neurophysiological investigations?
electroencephalogram (EEG), EEG video monitoring
Advanced investigations?
in pts. with intractable focal epilepsy where surgery is considered
1. Neuropsychology
2. Semiinvasive or invasive EEG recordings
3. MR Spectroscopy
4. Positron emission tomography (PET)
5. ictal Single-photon emission computed tomography (SPECT)
When is surgery necessary?
in intractable cases
- the treatment target is seizure freedom and improvement of quality of life
What are the basic rules of drug treatment?
- Drug treatment should be simple, preferably using one anticonvulsant (monotherapy)
- “Start low, increase slow“. - Add-on therapy is necessary in some patients
What anticonvulsant treatment is used in epilepsy?
- Carbamazepine
- Sodium valproate
- Lamotrigine (first line drugs)
- Levetiracetam
- Topiramate
- Pregabaline (second line drugs)
- Zonisamide
- Eslicarbazepine
- Retigabine (new AEDs)
Treatment for generalized absence seizures?
- etosuximide
- valproate
Treatment for partial tonic-clonic/simple/complex seizures?
- phenobarb
- phenytoin
- valporate
- carbamazepine
When to withdraw pharmacotherapy?
- If patient is seizure-free for three years
- Withdrawal should be carried out only if patient is satisfied that a further attack would not ruin employment etc. (e.g. driving license)
- It should be performed very carefully and slowly! 20% of pts will suffer a further seizure within 2 yrs
What drug has a risk of teratogenicity?
valproates
Describe the problems with pharmacotherapy in epileptic females?
- teratogenicity with valproates
- withdrawing drug therapy in pregnancy is riskier than continuation
- Epileptic females must be aware of this problem and thorough family planning should be recommended
NB: Over 90% of pregnant women with epilepsy will deliver a normal child.
What is drug intractable epilepsy?
Failed AED’s x 2
- affects 30% of patients
What could cause drug intractable epilepsy?
- Pseudo epilepsy.
- Compliance - Blood levels
- Temporal lobe epilepsy
Describe the surgical treatment for epilepsy?
- A proportion of the pts with intractable epilepsy will benefit from surgery
- Epilepsy surgery procedures:removal of epileptic focus) 50-80% success rate
What is neurostimulation?
- palliative treatment for patients with drug-resistant epilepsy who are not candidates for respective surgery
- Vagus nerve, deep brain stimulation showing a seizure reduction of 50% or more in more than a half of treated patients
What is status epilepticus?
A condition when consciousness does not return between seizures for more than 30 min
- This state may be life-threatening with the development of pyrexia, deepening coma and circullatory collapse
- Death occurs in 5-10%.
Causes of status epilepticus?
- frontal lobe lesions (incl. strokes)
- following head injury
- on reducing drug therapy
- with alcohol withdrawal
- drug intoxication
- metabolic disturbances
- pregnancy
Treatment of status epilepticus?
- AEDs intravenously ASAP
- general anesthesia with propofol or thipentone should be commenced immediately
