Neurology Flashcards
Pathophysiology of vasovagal syncope.
Strong stimulus to the vagus nerve causes parasympathetic activation.
Parasympathetic activation counteracts the sympathetic nervous system.
As a result, cerebral blood pressure drops leading to hypoperfusion, so the patient loses consciousness.
Symptoms of syncope.
Prodromal period:
- clammy
- sweaty
- heavy
- dizzy
- vision going blurry
- headache
Collateral history may reveal:
- sudden loss of consciousness
- unconscious for a few minutes
- twitching, shaking
Causes of primary syncope.
- dehydration
- missed meals
- extended standing in a warm environment
- vasovagal response to stimuli (e.g. surprise, pain, blood)
Causes of secondary syncope.
- hypoglycaemia
- dehydration
- anaemia
- infection
- anaphylaxis
- arrhythmias
- valvular heart disease
- HOCM
Syncope vs Seizure.
What examinations are required following syncope?
- secondary survey looking for injuries
- neurological examination
- cardiac examination (pulses, heart rate, rhythm, mumur)
- lying and standing BP
Syncope investigations.
- ECG
- 24hr ECG
- echocardiogram
- FBC (?anaemia)
- U&Es (?arrythmia ?seizure)
- blood glucose (?diabetes)
Management of fainting in children.
Common and usually resolve by the time they reach adulthood.
Once a simple vasovagal episode is diagnosed, simple advice can be given:
- avoid dehydration
- avoid missing meals
- avoid standing for long periods
Secondary syncope may require further investigation and referral to specialist.
What is a generalised tonic-clonic seizure?
Loss of consciousness with:
- tonic (muscle tensing)
- clonic (muscle jerking)
There may be associated tongue-biting, incontinence, groaning and irregular breathing.
After the seizure there is a prolonged postictal period where the person is confused, drowsy and irritable.
Management of tonic-clonic seizures.
First line: sodium valporate
Second line: lamotrigine or carbamazepine
What area of the brain is affected in focal seizures?
Start in the temporal lobes, therefore affect:
- hearing
- speech
- memory
- emotions
Presentations of focal seizures.
- hallucinations
- memory flashbacks
- déjà vu
- doing strange things on autopilot
Management of focal seizures.
First line: carbamazepine or lamotrigine
Second line: sodium valporate
What are absence seizures?
Patient becomes blank, stares into space and then abruptly returns to normal after around 20 seconds.
During these episodes they are unaware of their surroundings.
Management of absence seizures.
First line: sodium valporate or ethosuximide.
Most common in children; 90% stop having absence seizures as they get older.
What are atonic seizures?
Brief lapses in muscle tone causes the patient to collapse.
May be indicative of Lennox-Gastaut syndrome.
Management of atonic seizures.
First line: sodium valporate
Second line: lamotrigine
What are myoclonic seizures?
Sudden brief muscle contractions, causing a sudden ‘jump’.
The patient usually remains awake during the episode.
Management of myoclonic seizures.
First line: sodium valporate
Second line: lamotrigine
What are infantile spasms?
A rare syndrome starting in infancy, characterised by clusters of full body spasms.
Prognosis of infantile spasms.
1/3 die by age 25.
1/3 are seizure free at age 25
Management of infantile spasms.
Difficult to manage:
- prednisolone
- vigabatrin
What age child is typically affected by febrile convulsions?
6 months to 5 years
Differentials to epilepsy.
- vasovagal episodes
- febrile convulsions
- encephalitis
- meningitis
- sepsis
How are seizures investigated?
- EEG
- MRI brain (?structural problems)
- ECG (?heart defects)
- U&Es (Na, K, Ca, Mg)
- blood glucose (?hypoglycaemia)
- blood culture, urine culture & LP (?sepsis, encephalitis, meningitis)
What general advice should be given to families presenting with seizures?
- showers instead of baths
- supervised if swimming
- cautious with heights
- cautious with traffic
- cautious with heavy, hot or electrical equipment
Older teenagers must avoid driving unless they meet specific criteria regarding control of their epilepsy.
MOA of sodium valporate.
Increasing the activity of GABA, having an inhibitory effect on the brain.
Sodium valporate SEs.
- teratogenic*
- liver damage and hepatitis
- hair loss
- tremor
*avoided in girls unless there are no suitable alternatives and strict criteria are met to ensure they do not get pregnant.
SEs of carbamazepine.
- agranulocytosis
- aplastic anaemia
- CYP P450 inducer
Phenytoin SEs.
Folate deficiency:
- megaloblastic anaemia
Vitamin D deficiency:
- osteomalacia
Lamotrigine SEs.
- Stevens-Johnson syndrome
- leukopenia
Management of seizures (general).
- put patient in a safe position
- place in the recovery position
- put something soft under patient’s head
- remove obstacles that could lead to injury
- time the seizure
- call an ambulance if lasting >5 minutes or if this is their first seizure
What is status epilepticus?
Seizure lasting longer than 5 minutes
or
2 or more seizures without regaining consciousness
Management of status epilepticus.
- A-E
- high-concentration oxygen
- IV lorazepam
- rpt IV lorazepam after 5 mins
- IV phenobarbital / phenytoin after 5 mins
What are simple febrile convulsions?
Generalised, tonic clonic seizures.
Last less than 15 minutes.
Only occur once during a single febrile illness.
What are complex febrile convulsions?
- partial seizure
- focal seizure
Last more than 15 minutes.
Occur multiple times during the same febrile illness.
Differentials for febrile convulsions.
- epilepsy
- meningitis
- encephalitis
- sepsis
- space occupying lesions
- syncope
- electrolyte abnormalities
- trauma (NAI)
Management of febrile convulsion.
- identify and manage underlying source of infection
- control fever with paracetamol / ibuprofen
Prognosis of a simple febrile convulsion.
No increased risk of epilepsy compared to normal population.
Prognosis of complex febrile convulsion.
Around 10% of children go on to develop epilepsy.
What are breath holding spells?
Involuntary episodes where a child holds their breath, usually triggered by something upsetting or scary.
What aged children are usually affected by breath holding spells?
6 to 18 months of age.
Most children outgrow them by 4 to 5 years.