Neurology Flashcards
Describe the pathophysiology behind vasovagal syncope’s
- Dysregulation of autonomic nervous system
- Stimulus (e.g. emotional event, pain, change in temp, standing for too long) can stimulate parasympathetic nervous system. (Usually triggered by reduced venous return which causes ventricles to contract vigorously in attempt to maintain CO; ventricular mechanoreceptors triggered and they stimulate parasympathetic system)
- Causes vasodilation and bradycardia
- Vasodilation of carotid arteries decreases blood supply to head
- Decreasing blood pressure in cerebral circulation
- Leads to hypoperfusion of brain
State some potential causes of syncope
- Dehydration
- Missed meals/not eaten enough
- Standing for long periods
- Warm environment
- Stimuli e.g. surprise, pain, sight of blood
Once a simple vasovagal syncope has been diagnosed, reassurance and advice can be given; what advice would you give?
- Avoid dehydration
- Avoid missing meals
- Avoiding standing for long periods
- When experiencing prodromal symptoms (hot, sweaty, heavy, dizzy, blurred vision, headache) sit or lie down. Try having something to eat & drink
What are febrile convulsions?
What ages do they occur in?
- Seizures due to/caused by high fever. (Usually occur during viral infection as temp rises rapidly)
- 6 months - 5yrs (occur in 3% children)
There are 3 types of febrile convulsions, compare each thinking about:
- Type of seizure
- Duration
- Frequency
Simple
- Generalised tonic clonic seizures
- Last <15 mins
- Only occur once during single febrile illness
Complex (have one or more of following)
- Partial or focal seizures (movement limited to one side of the body or one limb)
- Last >15 mins
- Recurrence within 24 hours or within the same febrile illness; or incomplete recovery within 1 hour.
Febrile Status Epilepticus
- Single seizure or a series of seizures without recovery between them that lasts at least 30 minutes
State some differential diagnoses for febrile convulsions
- Epilepsy
- Neurological infection e.g. meningitis, encephalitis, cerebral malaria
- Space occupying lesions e.g. tumour, intracranial haemorrhage
- Syncopal episode
- Electrolyte abnormalities
- Trauma (always consider non-accidental injury)
How do you diagnose febrile convulsions?
Must exclude other neurological pathology first e.g.
- Epilepsy
- Meningitis, encephalitis or another neurological infection such as cerebral malaria
- Intracranial space occupying lesions, for example brain tumours or intracranial haemorrhage
- Syncopal episode
- Electrolyte abnormalities
- Trauma (always think about non accidental injury)
Simple febrile convulsions do not require further investigations however complex febrile convulsions may.
Discuss the management of febrile convulsions
- Children who have had first seizure or any features of complex seizure should be admitted to paediatrics
- Identify & manage underlying infection (e.g. abx if required)
- Control fever with simple analgesia (e.g. paracetamol, ibuprofen)
- Reassure & educate parents
- Give parents advice on how to manage seizure at home:
- Stay with child
- Put in safe place away from potential sources of injury e.g. on carpet with pillow under head
- Put in recovery position
- Don’t put anything in their mouth
- Call ambulance if lasts >5mins
- Following convulsion visit GP to be checked over
- May consider teaching parent how to use buccal midazolam or rectal diazepam
Do febrile convulsions usually cause lasting damage?
How many infants/children will have another febrile convulsion?
- No
- 1 in 3
Do febrile convulsions increase risk of epilepsy?
Epilepsy risk in…
- General population 1.8%
- After a simple febrile convulsion 2-7.5%
- After a complex febrile convulsion 10-20%
What are seizures?
What is epilepsy?
- Seizures= sudden transient episode of abnormal electrical activity in the brain
- Epilepsy= a condition in which a person has a tendency towards recurrent seizures that are unprovoked by systemic or severe neurological insult
Epilepsy most commonly occurs in isolation however there are some conditions that are associated with epilepsy; name 3
- Cerebral palsy (30% have epilepsy)
- Tuberous sclerosis
- Mitochondrial diseases
Discuss how we classify seizures
Classify based on:
- Where in brain seizure began
- Level of awareness during seizure
- Other features of seizure
State some different types of seizures
- Generalise tonic clonic
- Focal seizures
- Absence seizures
- Atonic seizures
- Myoclonic seizures
Discuss what is meant by generalised seizures, include:
- Where they occur in brain
- Consciousness
- Subdivisons
- Involve both sides of brain at the onset
- Consciousness lost immediately (therefore don’t classify level of awareness in generalised seizures)
- Subdivisions, can be classified into motor & non-motor:
- Tonic-clonic (grand mal)- M
- Tonic- M
- Clonic- M
- Myoclonic- M
- Atonic -M
- Absence (petit mal)- NM
For generalised tonic-clonic seizures, discuss:
- What motor activity is observed
- Muscle tensing (tonic) and muscle jerking (clonic) movements; typically tonic phase before clonic phase
For myoclonic seizures, discuss:
- Consciousness
- Motor action
- Can be focal (therefore may or may not lose consciousness) or generalised (therefore will lose consciousness); typically consciousness preserved.
- Sudden brief muscle contractions
For atonic seizures, discuss:
- Consciousness
- Motor action
- Can be generalised of or focal onset but degree of awareness not usually specified
- Also known as ‘drop attacks’ as there is a a paroxysmal loss in muscle tone so they drop to the ground
For absence seizures, discuss:
- Consciousness
- Motor action
- Generalised onset therefore consciousness is lost
- Two subtypes:
- Typical: becomes blank, stares into space, may appear to be ‘day dreaming’ then suddenly return to normal. Unaware of surroundings during episode & won’t respond
- Atypical: last longer, start & end more slowly, may be able to respond to someone, may be able to move around but may be clumsy & floppy
For tonic seizures, discuss:
- Consciousness
- Motor action
- May be generalised or focal so may or may not lose consciousness
- Muscles tense/tighten and body goes stiff- often results in falling to floor if standing. If generalised, will affect both sides of body. If focal, may only affect one area of body.
For clonic seizures, discuss:
- Consciousness
- Motor action
- Can be generalised or focal onset so may or may not lose consciousness
- Jerking movements. If generalised, affect whole body. If focal, affect one area.
Focal seizures may occur in the temporal lobe; what may a pt experience if the seizure is in the temporal lobe?
Hearing, speech, memory and emotion may be affected:
- Hallucinations
- Memory flashbacks
- Deja vu
- Doing strange things on autopilo
Pts who have generalised seizures may have associated symptoms/signs/actions; state some of these
- Tongue/cheek biting
- Incontinence
- Irregular breathing
- Excessive salivation
Following a seizure, pts may have post-ictal period; what may they experience in the post-ictal period?
- Confused
- Drowsy
- Tired
- Irritable
- Low in mood
Summary of seizure types
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A good history is key to diagnosing epilepsy as it allows you to establish whether the episodes were seizures or other pathology. State some key aspects of history
- Before: dizziness, light-headedness, hot, pain,what were they doing, triggers/stimulus, aura
- During: lose consciousness or not, motor activity like, how long did it last, associated actions (e.g. tongue biting, incontinence), any injuries
- After: how did they feel, recover quickly or ‘off’, did they remember the episode, tired
- PMH, drugs & allergies
-
FH
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What investigations are done when diagnosing epilepsy?
- Electroencephalogram (EEG)
- MRI brain: to diagnose structural problems that may be causing seizures e.g. tumours. Consider if first seizure <2yrs, focal seizures, no response to anti-epileptics
- Additional investigation to exclude other extra-cranial pathology that may cause seizures:
- ECG
- Plasma glucose
- U&Es
- Calcium
- Magnesium
- Blood culture, urine cultures, LP (if suspect sepsis, meningitis, encephatlitis)
Management of epilepsy can be broadly split into: education & advice, medication & the specific management of seizures. What would you educate and advise parents about if their child has epilepsy?
- Avoidance of situations that may put child, or others, in danger if they were to have a seizure: take showers rather than baths, cautious with swimming (must be well controlled and closely supervised), cautious with heights, cautious with traffic, cautious with heavy/hot/electrical equipment, if adolescent must comply with DVLA guidance
- Avoidance of known triggers
-
How to manage seizures at home:
- Stay with child
- Put in safe place away from potential sources of injury e.g. on carpet with pillow under head
- Put in recovery position
- Don’t put anything in their mouth
- Make note of start time. Call ambulance if >5 mins
- Buccal midazolam or rectal diazepam
There are a variety of anti-epileptic medications. Which antiepileptics are used for which types of seizure?
As a general rule:
- Generalised seizures: sodium valproate is first line
- Focal seizures: carbamazepine is first line
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State some common side effects of all anti-epileptic drugs
- Sedation
- Dizziness
- Suicidal thoughts
- Nausea & vomiting
For sodium valproate, state:
- Mechanism of action
- Side effects
- Increases GABA activity to have inhibitory effect on brain
- Side effects:
- Teratogenic
- Hepatitis & liver damage
- Hair loss
- Tremor
For carbamazepine, state:
- Mechanism of action
- Specific side effects
- Binds to and blocks Na+ channel in the inactivated state and increases refractory period
- Side effects:
- Agranulocytosis
- Aplastic anaemia
- Visual disturbances
- SIADH
- Induces P450 system so many drug interactions
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For phenytoin, state:
- Mechanism of action
- Specific side effects
- Binds to and blocks Na+ channels when in inactivated state and increases their refractory period
- Side effects
- Folate & vit D deficiency
- Megaloblastic anaemia (folate deficiency)
- Osteomalacia (vit D deficiency)
- Peripheral neuropathy
For lamotrigine, state:
- Mechanism of action
- Specific side effects
- Binds to and blocks sodium channels when in inactivated state and increases refractory period
- Side effects:
- Stevens-Johnson syndrome or DRESS syndrome
- Leukopenia
For ethosuximide, state:
- Mechanism of action
- Specific side effects
- Calcium channel blocker
- Side effects:
- Night terrors
- Rashes
What is status epilepticus?
Medical emergency in which pt has has either a single seizure lasting more than 5 minutes or >/= 2 seizures within 5 minute period without person returning to normal inbetween