Epilepsy Flashcards
What is epilepsy?
A group of neurological disorders characterised by epileptic seizures
What are epileptic seizures?
Episodes that vary from brief, nearly undetectable periods, to long periods of vigorous shaking
What is a seizure?
A paroxysmal abnormality of motor, sensory, autonomic, and/or cognitive function due to transient brain dysfunction
What does the term ‘seizure’ include?
- Epileptic
- Syncopal (anoxic)
- Brainstem
- Emotional
- Functional
- Undetermined
What are the types of brainstem seizures?
- Hydrocephalic
- Coning
What are functional seizures also known as?
Psychogenic pseudo-seizures
What makes a seizure epileptic?
The nature of the underlying electrical activity in the brain, especially the cerebral cortex
What is the problem with the thing that makes seizures epileptic being the nature of the underlying electrical activity in the brain?
They can be difficult to distinguish from a non-epileptic seizure clinically
What are epileptic seizures due to?
Excessive and hypersynchronous electrical activity, typically in neural networks in all or part of the cerebral cortex
When can an epilepsy generally be recognised?
After two or more unprovoked epileptic seizures
What is the incidence of epilepsy in childhood?
0.05%
How does the incidence of epilepsy in children compare to other age groups?
It affects infants and children more than any other age group
What are seizures, in terms of pathophysiology?
A paroxysmal manifestation of the electrical properties or the cerebral cortex
When does a seizure result?
When there is a sudden imbalance between the excitatory and inhibitor forces within the network of cortical neurones in favour of sudden-onset net excitation
What % of epilepsies are genetic?
70-80%
What is meant by ‘genetic’ epilepsies?
Idiopathic syndromes with complex inheritance
What are the other causes of epilepsy?
- Cerebral dysgenesis/malformation
- Cerebral vascular occlusion
- Cerebral damage
- Cerebral tumour
- Neurodegenerative disorders
- Neurocutaneous syndromes
Give two examples of causes of cerebral damage that can lead to epilepsy
- Congential infection
- Hypoxic-ischaemic encephalopathy
Give an example of a neurocutaneous syndrome that can cause epilepsy
Tuberous sclerosis
What are the risk factors for epilepsy
Family history
What can epilepsies be broadly classified as?
- Generalised
- Focal
When do focal seizures occur?
When the seizures arise from one or part of the hemisphere
What does the manifestation of focal seizures depend on?
The part of the brain where the discharge originates and moves too
What happen to the level of consciousness during focal seizures? `
May be retained or lost
How can a focal seizure progress?
May evolve to a generalised secondary tonic-clonic seizure
What region of the brain do frontal seizures affect?
The motor or pre-motor cortex
How might frontal seizures present?
- Clonic movements, which may travel proximally (Jacksonian march)
- Tonic seizure with both upper limbs raised high for several seconds
How might temporal seizures present?
- Aura
- Smell or taste abnormalities
- Distortion of sound and shape
- Automatisms, e.g. lip smacking, plucking at one’s clothing
- Deja-vu
How might occipital seizures present?
- Stereotyped visual hallucinations
How might parietal seizures present?
- Contralateral dysesthesias
- Distorted body image
What is dysesthesias?
Altered sensation
What are generalised epileptic seizures?
Where discharges arise from both hemispheres
What are the types of generalised epileptic seizures?
- Absence
- Myoclonic
- Tonic-clonic
- Atonic
How do absence seizures present?
Transient loss of consciousness, with abrupt onset and termination unaccompanied by motor phenomena apart from some flickering of eyelids and minor alteration in muscle tone
What can absence seizures often be precipitated by?
Hyperventilation
How do myoclonic seizures present?
Brief, often repetitive jerking movements of the limbs, neck, or trunk
How do tonic seizures present?
Generalised increase in tone
How does the tonic phase of tonic-clonic seizures present?
- May fall to ground
- Do not breath, become cyanosed
What might happen when the patient falls to the ground in tonic-clonic seizures?
May injure themselves
What happens in the clonic phase of tonic-clonic seizures?
- Jerking of limbs
- Breathing is irregular and cyanosis persists
- Saliva may accumulate in mouth
- Biting of tongue
- Incontinence of urine
How long do tonic-clonic seizures last?
From a few seconds to minutes, followed by unconsciousness or deep sleep for up to several hours
How do atonic seizures present?
Transient loss of muscle tone, causing sudden fall to floor or drop of head
What are atonic seizures often preceded by?
Myoclonic jerk