Neurological Problems Flashcards
What are the different types of neurological problems
- Epilepsy
- Migraines and headaches
- Multiple sclerosis
- Myasthenia Gravis
- Myotonic dystrophy
- Idiopathic intracranial hypertension (idiopathic)
- Stroke
- Bell’s palsy
- Subarachnoid haemorrhage
- Cerebral vein thrombosis
- Posterior reversible encephalopathy syndrome
- Entrapment neuropathies
What is epilepsy?
- seizure (neurons synchronously active) disorder
- A neurological condition characterised by recurrent seizures
- Seizure are due to brief distributions in the electrical functions of the brain
- Caused by abnormal electrical discharge of cortical neurones (nerve cells)
- During a seizure clusters of neurons in the brain become temporarily impaired and starts to suddenly send excitatory signals over and over- paroxysmal.
- This occurs due to either too much excitation or too little inhibition.
Why do epileptic fits happen?
- Idiopathic
- Physical causes: head injury, cerebral tumours, stroke, hypertension, infection
- Metabolic causes: hyperglycaemia, hypoxia, uraemia, fluid and electrolyte imbalance, hyper or hyponatraemia
o Metabolic anomalies: Alteration in cell membrane properties due to abnormal blood concentrations on various ions/electrolytes - Syndromes: Antiphospholipid, Alzheimer’s, Wernicke-Karsakoff (thiamine B1 deficiency), Wilson’s disease
- Congenital defects: cerebral palsy, intracranial cysts
- Infection
- Postdural puncture
- Gestational epilepsy (idiopathic)
- Pseydoepilepsy/ non-epileptic seizure disorder
- Eclampsia
- Cerebral Vein thrombosis
- Thrombotic Thrombocytopenic purpura (TTP)
- Stroke
- Subarachnoid haemorrhage
- Drugs and alcohol (withdrawal)
What are the different types of fits?
Partial fits
- Simple partial
- Complex partial
- Secondary generalised
Generalised seizures: whole brain
- Absence
- Myoclonic
- Tonic
- Atonic
What are the partial fits?
commonly affects temporal lobe
o Simple partial: remain conscious, experience and aura, change in the way things look, smell, taste or sound, pins and needles in the arm, déjà vu.
o Complex partial: change in awareness, loses memory of the event, rubbing of hands, smacking of lips: chewing, fiddling with objects.
o Secondary generalised: partial seizures begin in one part of the brain and spread to the whole brain and tonic clonic seizures occur.
What are the generalised seizures?
o Absence: staring and blinking, daydreaming, mainly affects children and lose awareness for 5-20 seconds
o Myoclonic: brief muscle jerking or one or both arms and legs. Last a fraction of a second and remains conscious.
o Tonic: all muscles of the body contract causing falling but with convulsions. Lasts <20 seconds
o Tonic clonic: most common seizures with two stages: whole body convulse/twitch. Lasts 1-2 minutes with possible incontinence
o Atonic: all muscle tone lost very briefly; fall limpy to the ground. Head injury likely to occur. No confusion likely to get up after
What are the precipitating factors for seizures?
- Sleep deprivation/physical exhaustion
- Emotional stress
- Increased body temperature
- Environmental factors: flashing lights
- Menstruation
- Metabolic disturbances
- Excessive alcohol/drug misuse
- Certain medication
- Non-compliance with drug therapy
What are the key investigations?
- Clear history & eyewitness accounts of seizures (Most already with
- known history of epilepsy)
- Blood pressure measurement +obs, urinalysis
- Blood tests
o Haematology (FBC, platelets, coagulation screen, blood fil, thrombophilia screen)
o Biochemistry (U&Es, urate, glucose, serum calcium and sodium, LFTs)
o Toxicology screening - Computerised tomography scan (CT scan)
o Look for evidence of cerebral structural damage - Magnetic resonance imaging (MRI)
o More detailed view of brain structural changes - Electroencephalogram (EEG)
o Classifies seizure type by identifying origin of abnormal electrical discharge
o Gives you the diagnosis- tells you where the seizure is - Telemetry
o Uses video & EEG in order to observe & identify seizure type
What are the managements of epilepsy?
- Aims to identify cause of seizures & prevent recurrence (if possible)
- Usually requires anti-epileptic drugs (AED) which may be lifelong; complete control gained in 70%+ of cases
- Majority treated with monotherapy; 5-10% require polytherapy; a few will require surgery
- Aim of therapy is to use lowest possible dose of AEDs in order to control seizures, as all drugs have side effects
- Dosage needs to be adjusted during weight gain (pregnancy) and weight loss (illness)
What do you do when someone is having an epileptic fit?
- A –Assess the situation – are they in danger of injuring themselves? Remove any nearby objects that could cause injury
- C -Cushion their head (with a jumper, for example) to protect them from head injury
- T – Time, Check the time – if the seizure lasts longer than five minutes you should call an ambulance
- I – Identity, Look for a medical bracelet or ID card – it may give you information about the person’s seizures and what to do
- O –Over, Once the seizure is over, put them on their side (in the recovery position). Stay with them and reassure them as they come round
- N – Never restrain the person, put something in their mouth or try to give them food or drink
What are anti-epileptic drugs?
- These are anticonvulsant drugs
- Usually they act by suppressing the hyperexcitability of neurons in the cerebral cortex
- Some act by enhancing the activity of the inhibitory neurotransmitter, GABA (gamma aminobutyric acid)
- Common side-effects of AEDs (dose-related)
- Drowsiness, irritability, vertigo, double vision, poor memory, loss of concentration, weight gain/loss
- Most people with epilepsy (70-85%) can control recurrent seizures adequately with these drugs
Enzyme-inducing dugs
- Drugs that cause the liver to increase its production of certain enzymes
o Can result in increased rate of breakdown of drugs
o Can reduce effectiveness of oral contraceptive pill
Examples: - Carbamazepine (“Tegretol”)
- Phenytoin (“Epanutin”)
- Topiramate (“Topamax”)
- Primidone (“Mysoline”)
- Oxcarbazepine (“Trileptal”)
- Phenobarbitone
Non-enzyme inducing drugs
- These drugs do not have the same effect on liver enzymes and are not thought to interfere with effectiveness of oral contraceptive pill Examples: - Sodium valproate (“Epilim”) - Gabapentin (“Neurontin”) - Clonazepam (“Rivotril”) - Vigabatrin (“Sabril”) - Zonisamide (“Zonegran”)
What are the complications of epilepsy?
- Status epilepticus – repeated seizures without any recovery of consciousness
- Trauma – occurring at the time of the convulsion i.e. tongue biting, head trauma, hot water burns
- Cardio-respiratory failure – arising from status epilepticus where treatment was delayed
- Sudden Adult Death – Phenomenon whereby patient dies suddenly and no toxicological or anatomic cause of death is apparent
o Sudden unexpected death in epilepsy (SUDEP)
o High seizure frequency
o Polytherapy to control condition (> 3 drugs)
o Early-onset epilepsy
o Poor compliance/concordance with medication regime
What is the pre-conception issues and care?
- All women should be offered preconception counselling
- Pregnancy deferred until seizure control is optimal
- Current medication should be reviewed and changed if necessary
- AEDs: Increased risk of folate deficiency and therefore neural tube defects= 5mg folic acid before and up to 12/40
- Women who have been seizure free for a minimum of 5yrs may consider withdrawing AEDs
- AEDs should be used at the lowest number and dose of drugs possible as polytherapy = ↑Major Congenital Malformations
What are the effects of pregnancy on epilepsy?
- Usually, no effect on frequency of seizures
- If seizure free for many years → unlikely in pregnancy if good meds compliance
- Poorly controlled epilepsy → higher risk of deterioration
- If seizures of multiple types ↑ increase of frequency
- ↑ risk postpartum (3.5 % intrapartum)
What are the possible reasons for perinatal deterioration?
- Hormonal changes of pregnancy
- Decreased plasma drug levels (pharmacokinetics and pharmacodynamics altered in pregnancy)
- Lack of sleep (end of pregnancy, during labour, postpartum)
- Lack of absorption of AEDs from the GI tract during labour
- Hyperventilation and stress
- Poor compliance with AED
- Change to less effective drugs because of the perceived lower risk of teratogenicity
- Decreased drug levels related to nausea and vomiting
- Pharmacokinetic changes with decreased plasma antiepileptic drug levels, particularly lamotrigine
- ↓ gastrointestinal absorption and ↑hepatic and renal clearance resulting in insufficient drug levels
Effects on epilepsy on pregnancy
- Short episodes of hypoxia appear to be tolerable by the fetus (possible bradycardia, but no long-term effects)
- No increased risk of miscarriage or obstetric complications (unless trauma)
- Status epilepticus is rare, but dangerous for both mother and baby (1-2.5% of all pregnancies of WWE)
- ↑ of child to develop epilepsy, too
If another sibling is affected, the risk is 10%
o If both parents epileptic, the risk is 15-20%
o If mother with idiopathic epilepsy with early onset (less than 10y old), ↑ of child to develop epilepsy - ↑ of congenital anomalies due to meds
Teratogenicity
- All cross the placenta and teratogenic
- Carbamazepine (2.2%), phenobarbitone, phenytoin (3.7%), sodium valproate (6.2% risk)
- The effects of newer anticonvulsants are not known as fully as for other medications - vigabatrin, gabapentin, lamotrigine (3% risk)
- Dose dependant teratogenic effects for SV and Lamotrigine
- Higher risk with polytherapy
Complications in pregnancy
- Aetiology unclear - ?genetics, ? Seizures, ? AEDs
- Fetal abnormalities
- Spontaneous abortion
- Stillbirth
- Placental defects
- Placental abruption
- Pre-term labour
- Hypertensive disorders
- Haemorrhage
What is the role as a MW
- Detailed history taking with emphasis on current drug therapy
- Referral to specialist care- consultant led
- Ongoing support
- Advice on safe self care and safe baby care
- Liaison with multidisciplinary team
- Foster positive partnership
- Be informed (CPD) and use evidence based approach
Antenatal care
- 5mg folic acid up to 12/40 if not already
- Women taking sodium valporate should continue with 5mg FA for the remainder of the pregnancy
- Serum screening with AFP for neural tube defects
- Detailed USS at 18-22 weeks to screen for anomalies
- Women taking AEDs should receive 10mg Vit K PO from 36/40 or 4 weeks before delivery
- Adviced not to have a bath alone
- Encourage to register with UK Epilepsy and Pregnancy Register
- MDT care – obstetrician, neurologist, midwife
- Advise against hot baths and steamy environments
- Ascertain expectations and educate re potentially dangerous plans i.e. water births
Intrapartum care
- Risk of seizures increase around the time of delivery
- Increased stress, lack of sleep, over breathing, pain, dehydration
- 2-3% will have a grand mal seizure
- Prolonged or repeated seizures = fetal hypoxia
- Pethidine is metabolised to norpethidine and may induce a seizure therefore its use should be avoided in labour
- Epidural (early)
- One to one care should be provided, do not leave alone in a single room
- Most women with epilepsy have normal vaginal deliveries and CS is only required if there are recurrent generalized seizures in late pregnancy or labour.
What is the management of status epilepticus?
- Senior obstetric and anaesthetic staff to be present
- Maintain airway – recovery position, do not restrain
- Ensure safe environment
- Oxygen therapy – 6-10L/min via face mask
- Initial Rx magnesium sulphate (just in case eclampsia)
- Prolonged seizures – lorazepam 4mg (less sedative and longer acting than diazepam)
- Seek advise from neurologist if not effective
- Consider IV phenytoin with continuous EEG monitoring
- If not successful paralyse and sedate woman, ventilate mechanically
- Consider delivery of fetus at this point
- If CTG undertaken will initially be bradycardic, reduced baseline variability and decelerations for up to 30mins post seizure
Postnatal care
- During the 1st 24hrs 1-2% chance of grand mal seizures
- Physiological changes of pregnancy reversed = ↑AED levels
- AEDs interfere with Vit K metabolism in the neonate = possible haemorrhagic disease = 1mg Vit K IM at delivery
- Encourage BF: AEDs are secreted but less than therapeutic level for neonates and less that that received in utero
- Sedation, poor feeding, hypotonia and respiratory distress occasionally seen in neonates with increased AED levels
- Advise women how to minimise risks when caring for the baby in case of seizure; risk assessment