Fits, Faints and Funny Turns (Seizures and Seizure-mimics) Flashcards
Terminology for paroxysmal events:
what is a Seizure/Fit?
Any sudden attack from whatever cause
Seizures can have different mechanisms
Many seizures are not epileptic in nature
Terminology for paroxysmal events:
what is Syncope?
Faint (a neuro-cardiogenic mechanism)
Terminology for paroxysmal events:
what is Convulsion?
Seizure where there is prominent motor activity
Epileptic seizure: an _________ phenomenon
electrical
what is a epileptic seziure?
•An abnormal excessive hyper synchronous discharge from a group of (cortical) neurons
Seizures are bursts of electrical activity in the brain that temporarily affect how it works. They can cause a wide range of symptoms
- It may have clinical manifestations
- Paroxysmal change in motor, sensory or cognitive function
- Depends on seizure’s location, degree of anatomical spread over cortex, duration
what is epilepsy?
- A tendency to recurrent, unprovoked (spontaneous) epileptic seizures
- A question that must be answered clinically, with recourse to EEG only for supportive evidence
- A seizure is not necessarily epileptic
- Consequences of misdiagnosis of epilepsy can be serious
In childhood many mimics of epileptic seizures
What are some non-epileptic seizures and other mimics in children?
- Acute symptomatic seizures: due to acute insults eg. Hypoxia-ischaemia, hypoglycemia, infection, trauma
- Reflex anoxic seizure: common in toddlers (always provoked e.g. frightening experience, upset, excitement) due to vagal over activity, distinguish by good history
- Syncope (you can get convulsive syncopies)
- Parasomnias eg. night terrors
- Behavioural stereotypies
- Psychogenic non-epileptic seizures (PNES) (pseudoseziure) (are seizures that occur as a result of psychological causes, such as severe mental stress)
what is Febrile convulsion?
- An seizure occurring in infancy/childhood, usually between 3 months and 5 years of age, associated with fever but without evidence of intracranial infection or defined cause for the seizure
- Commonest cause of ‘acute symptomatic seizure’ in childhood
a convulsion in a child caused by a spike in body temperature, often from an infection. They occur in young children with normal development without a history of neurologic symptoms. It can be frightening when your child has a febrile seizure, and the few minutes it lasts can seem like an eternity
Distinguishing seizure types can be challenging
what are the different seizure types?
(These terms can be common to different types of seizures)
- Jerk/shake: clonic, myoclonic, spasms
- Stiff: usually a tonic seizure (increased tone)
- Fall: Atonic/tonic/myoclonic
- Vacant attack: absence, complex partial seizure
Myoclonic: Short jerking in parts of the body. Clonic: Periods of shaking or jerking parts on the body
what is the Mechanism of Epileptic Fit?
•Chemically triggered by:
- Decreased inhibition (gama-amino-butyric acid, GABA)
- Excessive excitation (glutamate and aspartate)
- Excessive influx of Na and Ca ions
- Chemical stimulation produces an electrical current
- Summation of a multitude of electrical potentials results in depolarization of many neurons which can lead to seizures, can be recorded from surface electrodes (Electroencephalogram)
what are the 2 Types of Epileptic Seizures
Depends on where in brain its coming from
Partial/focal = restricted to one hemisphere or part of one
Generalised – neurones recruited form both half’s of the brain
what is childhood epilepsy like compared to Adult onset epilepsies?
- Majority are idiopathic in origin (both Focal & Generalised)
- Majority of epilepsies are generalised
- Seizures can be subtle (absences, myoclonus, drop attacks)
- Diagnosis can be challenging
Diagnosis of epilepsy in children can be challenging because…
Non-epileptic paroxysmal disorders are more common in children
Difficulty in explaining (Children are not young adults)
Difficulty in interpretation (witness)
Difficulty in interpretation and synthesising information(physician)
Stepwise approach to a diagnosis of epilepsy - how should it be done?
- Is the paroxysmal event epileptic in nature?
- Is it epilepsy?
- What seizure types are occurring?
- What is the epilepsy syndrome? (certain types more common at different ages, EEG can help)
- What is the etiology?
- What are the social and educational effects on the child?
what is the role of a EEG?
- An interictal EEG has limited value in deciding when the individual has epilepsy (Sensitivity of first routine interictal EEG: 30- 60%)
- Problematic false positive rates: paroxysmal activity seen in 30%, frankly epileptiform activity in 5% of normal children
- Useful in identifying seizure types (focal orgeneralised), seizure syndrome and etiology
Epilepsy management: what is VNS (vagnus nerve stimulation?
Epilepsy surgery
Small proportion of patients with epilepsy may be suitable candidates for surgical techniques and can be divided into 2 – curative and palliative epilepsy surgery
If patient having drug refractory epilepsy then one technique is insertion of vagal nerve stimulation and is used to manage seizures on a palliative basis
Pulse generator implanted under clavicle, Have effect of suppressing seizures
The stimulator sends regular, mild electrical stimulations through this nerve to help calm down the irregular electrical brain activity that leads to seizures
epilepsy surgery:
what is shown here?
EEG from surface of brain
Trying to determine where in brain epileptic discharge is coming from
Helps localise origin of epileptic seizures and may facilitate resection which can cure the patient of seizures
