Epilepsy in pregnancy Flashcards
Define
A recurrent tendency to spontaneous, intermittent, abnormal electrical activity in part of the brain, manifesting as seizures in pregnancy
- Convulsions are the motor signs of electrical discharges.
- You need to have > 2 seizures for epilepsy to be diagnosed.
Epidemiology
- 1% of women of childbearing age
- 95% have a healthy baby
- Affects 0.5% of pregnant women
Classification of seizures
Focal Seizure: seizure localised to specific cortical regions e.g. temporal lobe seizure.
They originate within networks linked to one hemisphere and are often seen with underlying structural disease.
They can be further subdivided into:
SIMPLE partial seizure
- Consciousness/ awareness is NOT affected
- Focal motor, sensory (olfactory, visual etc.), autonomic or psychic symptoms
- No post-ictal symptoms
COMPLEX partial seizure
- Consciousness is affected
- Awareness impaired either at seizure onset or following simple partial aura.
- Most commonly arise from the temporal lobe, in which post-ictal confusion is a feature.
SECONDARY GENERALISED seizure
- Bilateral, convulsive seizure- the electrical disturbance from a partial seizure which starts focally and spreads widely, causing a generalised seizure.
- It is typically convulsive.
Generalised Seizure: seizures that affect the whole of the brain. It also affects consciousness.
- They originate at some point within, and rapidly engage bilaterally distributed networks which leads to simultaneous onset of widespread electrical discharge with no localising features referable to a single hemisphere.
There are different types of generalised seizures:
- Tonic-clonic
Loss of consciousness.
Limbs stiffen (tonic) then jerk (clonic)
May have one without the other
Post-ictal confusion and drowsiness
- Absence
Brief (10/- seconds) pauses, e.g. suddenly stops talking in mid-sentence, then carries on where left off.
Presents in childhood.
- Myoclonic
Sudden jerk of a limb, face or trunk.
The patient may be thrown suddenly to the ground, or have a violently disobedient limb.
- Atonic (akinetic)
Sudden loss of muscle tone causing a fall.
No LOC
Infantile spasms
Commonly associated with tuberous sclerosis.
Aetiology/ Risk factors
Aetiology
- Epilepsy
- Eclampsia
- Encephalitis or meningitis
- Space-occupying lesion (e.g. tumour, tuberculoma)
- Cerebral vascular accident
- Cerebral malaria or toxoplasmosis
- Thrombotic thrombocytopaenic purpura
- Drug and alcohol withdrawal
- Toxic overdose
- Metabolic abnormalities (e.g. hypoglycaemia)
Risk Factors
- If had previous seizure recently
- Sleep deprivation
- Stress
- Dehydration
- Lack of adherence to anticonvulsants, on multiple anticonvulsants
Symptoms and Signs
Key features to consider when taking a history from a potential epilepsy patient:
Rapidity of onset
Duration of episode
Any alteration in consciousness?
Any tongue-biting or incontinence?
Any rhythmic synchronous limb jerking?
Any post-ictal abnormalities (e.g. exhaustion or confusion)?
Drug history (alcohol, recreational drugs)
Investigations
Seizures (1st presentation) in the 2nd half of pregnancy, which can’t be attributed to epilepsy -> immediate treatment for eclampsia management until a definitive diagnosis is made by a full neuro assessment
- Basic observations
- Neurological (cranial nerve, upper and lower limb) examination
- Urine dipstick- rule out eclampsia
- AMTS/ MMSE if indicated
- EEG
Management
Seizures should be controlled with the minimum possible dose of the optimal anticonvulsant drug
PRECONCEPTUAL
- Alter medication according to seizure frequency
- NOTE: Sodium valproate should be AVOIDED ideally
- Carbamazepine + Lamotrigine are the safest (NOTE: Lamotrigine levels fall rapidly in pregnancy and are associated with increased seizure activity, necessitating an increased dose)
- Reduce to monotherapy where possible
- Stress importance of compliance with medication
- Pre-conceptional folic acid 5mg (-3 months before)
- Explain risk of congenital malformation
- Explain risk from recurrent seizures
ANTENATAL
- If pregnant unexpectedly- do NOT stop or change AEDs without an informed decision
- Foetal anomaly scan- 18+0 to 20+6 weeks
- Serial USS growth scans- from 28 weeks (look for SGA)
- Foetal echocardiography – important to exclude foetal abnormalities
- Vitamin K 10mg PO given from 36 weeks (NOT RECOMMENDED in RCOG 2016)
- Screen/ look out for depression, anxiety and neuropsychiatric symptoms
- Involve other specialties if needed
- Check drug levels- may need to increase dose if levels are low to get better coverage
INTRAPARTUM
- Able to have uncomplicated delivery
- Avoid seizure triggers: adequate hydration, sleep (where possible), pain relief/ de-stress
- Pain relief- early epidural (NOTE: pethidine lowers pain threshold so use with caution)
- Continuous CTG monitoring if high risk of seizure and/or following intrapartum seizure
- Benzodiazepines given if seizure in labour
POSTNATAL
- Continue AED use
- AED dosage- if increased, should be reviewed within 10 days
- Safety advice on how to look after the baby
- Don’t walk down the stairs with the baby, have the baby in a car seat
- Breastfeeding on the floor surrounded by cushions
- Don’t bathe the baby by yourself, have shallow water/ sponge baby
- Neurology follow up + depressive disorder screen in the puerperium
CONTRACEPTION
- Offer effective contraception to avoid unplanned pregnancies
- Copper IUD or LNG-IUS should be promoted as not affected by enzyme-inducing AEDs
- Counsel on risk of failure with some hormonal contraceptives if on enzyme inducing AEDs (e.g. carbamazepine, phenytoin, phenobarbital)
SUMMARY
- Risks of uncontrolled epilepsy generally outweigh risks of medication (however, aim for monotherapy)
- No indication to monitor antiepileptic drug levels
- Folic acid 5mg OD, and vitamin K in last month of pregnancy
- 3-4% risk of developing congenital defects (1-2% in non-epileptic mothers)
Medications/AEDs:
NO -> Sodium valproate -> neural tube defects
NO -> Phenytoin -> cleft palate
YES -> Lamotrigine -> lowest rate of congenital malformations (and levetiracetam)
YES -> Carbamazepine -> least teratogenic of the old antiepileptics
Complications
Epilepsy -> increased risk of congenital abnormality caused by anticonvulsant medication (2-3x increase) with the use of several AEDs further increasing risk à abnormalities associated with AEDs:
- Neural tube defects
- Facial clefts
- Cardiac defects
Other abnormalities: developmental delay, nail hypoplasia, IUGR and midface abnormalities
· Valproate is a teratogenic medication (avoid unless necessary)
These complications can often be detected in anomaly scans
Need to balance risk of AEDs with the effect of seizures à foetal and maternal hypoxia
Prognosis
- New-born has 3% risk of developing epilepsy
- No consistent effect of pregnancy on epilepsy (10-fold increase in mortality amongst pregnancy with epilepsy)
PACES
Most women who have epilepsy do not have a seizure during pregnancy and have healthy pregnancies and healthy babies.
You will be under the care of a specialist healthcare team, which will usually include an obstetrician, a midwife and a specialist healthcare professional.
You must not stop or change your epilepsy medication unless so advised.
Aim for monotherapy (explain that neurologist may consider changing the AED to something that is less associated with congenital abnormalities)
Risks of congenital abnormality (NTD, facial, cardiac)
- The epilepsy medication sodium valproate is known to cause harm to developing babies
Take a higher dose of folic acid (5mg OD) (until at least end of 1st trimester) and vitamin K in last month of pregnancy
You should be able to have a vaginal birth.
You are at increased risk of having seizures during labour and after birth, if this happens come back to us to review your meds. Taking your medication regularly and getting enough rest lowers this risk.
You will be advised to give birth in a consultant-led maternity unit with a special care baby unit so that you and your baby can get extra care if needed.
Gas and air, TENS machines and an epidural are all suitable for pain relief. Injections of a strong pain reliever such as diamorphine can also be used. Pethidine (another type of pain relief) is not recommended, because in high doses it has been linked with seizures.
Breastfeeding is safe even if you are taking epilepsy medication.
- It is safe to continue using all antiepileptic medications while breastfeeding as negligible amounts of the medication are passed to the baby through breast milk.
Invite to register to the UK Epilepsy and Pregnancy Register
