Week 5 Flashcards
Define a seizure?
A seizure is a transient alteration of brain function
due to uncontrolled depolarisation of cerebral
neurons
what are clinical signs of seizures?
alterations to: sensation, movement, awareness or consciousness, behaviour and perception.
What is epilepsy
Epilepsy is a condition encompassing a
broad range of seizure disorders and is diagnosed
in patients suffering recurrent seizures (Huff
& Fountain, 2011). Epilepsy is one of the most
common serious neurological dysfunctions
What is the third most common neurological
disorder in older people after dementia and stroke
epilepsy
What causes seizure activity
Seizure activity is the result of abnormal or uncontrolled neuronal depolarisation.
Define status epilepticus
‘a prolonged seizure lasting longer than five minutes’ or
‘multiple seizures occurring back to back without full recovery of consciousness in between’.
What are the types of febrile seizures?
Simple
Complex
What is a simple febrile seizure?
Simple febrile seizures are generalised, last less than 15 minutes and occur no more than once in 24 hours. They represent the majority of febrile seizures and carry few risks.
What are complex febrile seizures?
Complex febrile seizures last longer than 15 minutes, occur more than once within 24 hours and may display a focal component.
WHat are the clinical classifications of seizures?
Partial seizures:
- simple partial
- complex partial
Generalised seizures
Unclassifiable seizure types
WHat are the types of Generalised seizures?
Absence seizures Myoclonic seizures Clonic seizures Tonic seizures Tonic–clonic seizures Atonic seizures
What are the types of simple partial seizures?
Motor symptoms Sensory symptoms Special sensory symptoms Autonomic symptoms Psychic symptoms
What are the types of complex partial seizures?
Simple partial onset followed by impaired consciousness
Impairment of consciousness at onset
What are the common causes of provoked seeizures?
Drugs of abuse Infections/Inflammatory Iatrogenic Metabolic disorders Lesions Systemic causes
Define Partial seizures
Partial seizures generally involve only one
hemisphere of the brain and originate from
a particular cortical area of the brain.
Define simple partial seizures
Simple
partial seizures affect one part of the brain with
no impact on consciousness
Define complex partial seizures
complex
partial seizures affect more than one part of the
brain and may result in impairment or clouding
of consciousness.
Define generalised seizures
involve both hemispheres of
the brain and do not originate from one cortical
area. Generalised seizures always result in an
alteration to consciousness.
what are some differential diagnosis for seizures?
- Syncope
- Stroke
- Traumatic head injury
- migrane with aura
- movement disorder such as parkinsons
- toxic or metabolic encephalopathy
- sleep disorders
- psychogenic
what percentage of australians experience epilepsy?
3-3.5%
Epilepsy has an increased risk of death. what are some causes of this increased risk?
– underlying brain disease, eg tumour or infection.
– seizures in dangerous positions => drowning, burns, or head injury.
– prolonged seizures (status epilepticus).
– sudden and unexplained causes.
– cardiac arrest during a seizure.
– suicide.
What is the pathophys of epilepsy?
A group of neurones act as a focus for seizure activity, possibly due to changes in membrane potential stimulated by hypoxia, hyperthermia, hypoglycaemia, hyponatremia, brain injury and some drugs.
The primary cause may be a
defect in the GABA inhibitory
system or abnormality in excitatory transmission.
What is a seizure?
• A seizure results from widespread and
uncoordinated discharge of CNS neurones.
• Characterised by a sudden but transient
alteration in brain function, usually involving
“motor, sensory, autonomic, or psychic clinical
manifestations and an alteration in level of
arousal.”
• The seizure may produce focal or generalised
clinical signs.
What are some triggers for seizures?
- Alcohol ‐ Reduces the effect of medication
- Diet – Caffeine, Low BSL
- Infection/Illness ‐ High temp
- Lack of sleep
- Menstruation
- Smells / sounds
- Missed normal medication
- Other drugs
- Stress
- Severe changes to ambient temp
- Photosensitivity ‐ Flickering light (Ambulance strobes!!!!!!!)
What are the main causes of partial seizures?
stroke
tumour
head injury
what is an absence seizure?
– Awareness and responsiveness are impaired – Pt simply stare, eyes may roll back/eyelids flutter, may be hand movements. – Start suddenly & cannot be interrupted – Last a few seconds then stop suddenly => continue with activity – Last < 10 seconds – Can occur many times during day
What is an Atonic seizure?
– Known as “drop attacks” – affect muscle tone => Pt collapses to ground – usually remains conscious – can cause head/facial/other injury => unprotected fall – Recovery quite quick
What is a myoclonic seizure
– Brief, shock‐like jerks of a muscle/group of muscles – Lasting a second or two – Can be one, sometimes many will occur within a short timeframe
What is a tonic seizure?
– muscle tone is greatly increased – body, arms, or legs make sudden stiffening movements – often occur in clusters during sleep, but can occur when Pt awake => “heavy” fall – duration < 20 sec – remain conscious
what is a tonic-clonic seizure?
– body stiffens & fall to the ground (tonic phase)
– may cry/groan (air forced past the vocal cords)
– tongue/cheek may be bitten => bloody saliva
– limbs begin to jerk in strong, symmetrical, rhythmic
movements (clonic phase)
– Pt may dribble from the mouth, facial cyanosis/red,
loss of bladder and/or bowel control
– Tonic‐clonic seizures generally last 1 to 3 minutes
– On regaining consciousness Pt confused,
drowsy, agitated or depressed
– May C/o headache & want to sleep
– Drowsiness can last for hours
What is a secondary generalised seizure?
– Seizure activity spreads from focal point
across to both sides of brain => initially a
partial seizure
– Episode so brief Pt has no recall or
recognises it
– Lasts 1‐3 minutes
– Similar to primary generalized seizures
– Occur in 30% of Pts with partial seizures
What are the 3 phases of generalised seizures?
preictal
ictal
postictal
explain the preictal phase of generalised seizures?
– Period just before seizure. May involve aura, restlessness, nervousness, wandering.
explain the ictal phase of generalised seizures?
– Seizure period (eg tonic/ clonic) lasting a few seconds to minutes
explain the postictal phase of generalised seizures?
– Period after seizure (disorientation, confusion, salivation, unresponsiveness, incontinence).
what is status epilepticus?
• Is a neurological emergency characterised by a
series of convulsions, rapidly repeated without
intervals of consciousness, which if untreated
may lead to hypoxia, hyperthermia, cerebral
damage and death.
what are the effects of benzodiazapines?
– Anxiolytic – Muscle relaxant – Anticonvulsant – Hypnotic – Memory impairment
How do anticonvulsants work?
Enhance GABA transmission • Increase frequency of openings of GABA channels. • increase opening time of GABA channels. • increase receptor affinity for GABA. GABA (y-aminobutyric acid) is the main inhibitory CNS transmitter.
What are the adverse effects of benzodiazapines?
- CNS depression (including hypotension, respiratory depression, drowsiness leading to sedation,
impaired coordination and ataxia (mainly in the elderly), confusion and memory
loss) - Dependence may develop
- addictive effects
Define a febrile convulsion
“Seizures associated with fever in the absence
of CNS infection or acute electrolyte imbalance
in a young child (between 6 months and 6
years)
