Seizures/ Epilepsies

Introduction

A seizure results from abnormal excessive electrical discharge of brain cells.

Epilepsy is a condition characterized by recurrent seizures unprovoked by any immediate identifiable cause. It may be idiopathic or could follow:

Cerebral infections
Metabolic derangements (glucose, electrolytes, fluids)
Stroke
Tumours
Head trauma
Birth injury/asphyxia
Drug abuse/overdosage/withdrawal
Alcoholism
Neuro-degeneration

Clinical features

Classical attack with sudden loss of consciousness, convulsions (tonic and/or clonic)
Tongue biting
Abnormal sensation or perception
Autonomic disturbances: epigastric discomfort, sphincteric incontinence
Semi-purposive actions (automatisms)
Loss of postural tone (sudden falls without convulsions)
Aura
Limb paralysis (Todd’s paralysis) usually after attacks

Differential diagnoses

Migraine headache
Syncope
Narcolepsy
Panic attacks
Catatonic schizophrenia
Transient ischaemic attacks
Hysteria
Meniere’s disease

Complications

Status epilepticus
Cerebral hypoxia/anoxia resulting in brain
Cardiac arrhythmias
Renal failure from myoglobinuria damage
Sudden death

Investigations

Electroencephalography
Neuro-imaging: CT scan,
MRI
Random blood glucose
Urea,
Electrolytes and Creatinine

Treatment objectives

Stop convulsions/attacks
Treat underlying cause if identified
Improve quality of life

Drug treatment

1. Attacks/status epilepticus

Parenteral drugs are recommended for acute attacks/status epilepticus

Diazepam

Intravenous injection, 10 mg at a rate of 1 mL (5 mg) per minute, repeated once after 10 minutes, if necessary 200-300 micrograms/kg
or 1 mg per year of age or Under 12 years, 300 – 400 micrgrams/kg (max. 10 mg) (off label), repeated once after 10 minutes if necessary.
Could be given per rectum as rectal solution in restless patients
- 500 micrograms/kg (up to a maximum of 30 mg) in adults and children over 10 kg

Phenytoin

Adult: initially 15 mg/kg by slow
intravenous injection or infusion (with blood pressure and Electrocardiograph monitoring) at a rate not more than 50 mg/minute; then 100 mg every 6-8 hours
Child:
- neonate– initial loading dose 20 mg/kg by slow intravenous injection, then 2 – 4 mg/kg orally every 12 hours, adjusted according to response (usual maximum dose 7.5 mg/kg every 12 hours)
- 1 month – 12 years: initially 1.5-2.5 mg/kg every 12 hours, adjusted according to response to 2.5 5mg/kg every 12 hours (usual maximum dose 7.5mg/kg every 12 hours or 300 mg daily)
- 12 18 years: initially 75 – 150 mg every 12 hours, adjusted according to response to 150 – 200 mg 12 hourly (usual maximum 300 mg every 12 hours)

Paraldehyde (see important precaution below):

Useful where facilities for rescucitation are poor
Causes little respiratory depression when given rectally
Administer 10- 20 mL per rectum as an enema
Child
- neonate: 0.4 ml/kg (maximum 0.5 mL) as a single dose;
- up to 3 months: 0.5 mL;
- 3-6 months: 1 mL;
- 6-12 months: 1.5 mL;
- 1 – 2 years 2 mL;
- 3 – 5 years 3-4 mL;
- 6 -12 years 5-6 mL (administered as a single dose per rectum) per kg body weight
Not recommended in pregnancy

Cerebral decompression with mannitol
20% infusion or furosemide if indicated (see meningitis).

Give 50 mls of 50% Glucose to supply brain cells with calories.

Give Thiamine in case of alcohol withdrawal seizures.

Maintenance therapy in day-to-day care

2. Generalized epilepsies

Phenobarbital

Adult: 60-180 mg orally daily
Child: 5-8 mg orally daily

Phenytoin

Adult: 150-300 mg orally daily
Child:
- neonate– initial loading dose by slow intravenous injection then 2-4 mg/kg by mouth every 12 hours adjusted according to response (usual maximum 7.5 mg/kg every 12 hours)
- 1 – month 12 years: 1.5 – 2.5 mg/kg orally every 12 hours (usual maximum 7.5 mg/kg every 12 hours or 300 mg daily)
- 12 – 18 years: initially 75 – 150 mg every 12 hours, adjusted according to response up to 150-200 mg every 12 hours (usual maximum 300 mg every 12 hours)

Sodium valproate

Adult: 600mg daily in 2 divided doses
Child:
- neonate, initially 20 mg/kg orally or per rectum once daily; usual maintenance dose 10 mg/kg twice daily
- 1 month – 12 years: initially 5-7.5 mg/kg every 12 hours; maintenance 12.5-15 mg/kg every 12 hours
- 12-18 years: usually 300 mg every 12 hours, increased in steps of 200 mg at 3-day intervals; usual maintenance 500 mg – 1 g
  twice daily (maximum 1.25 g twice daily)

3. Partial seizures

Carbamazepine

Adult: 100-200 mg orally 1-2 times daily
Not recommended in pregnancy
Child
- 1 month 12 years: initially 5 mg/kg orally at night or 2.5 mg/kg twice daily, increased as necessary by 2.5-5 mg/kg every 3-7 days; usual maintenance 5 mg/kg every 8b- 12 hours
- 12-18 years: initially 100-200 mg 1 – 2 times daily, increased slowly to usual maintenance of 400-600 mg every 8-12 hours

4. Absence attacks

Ethosuximide

Adult: 500 mg daily initially,in two divided doses; increase by 250 mg at intervals of 5-7 days to doses of 1- 1.5 g dailyin two divided doses (maximum dose 2 g daily)
Child:
- over 6 years: same as adult dose
- 1 month to 6 years: initially 10 mg/kg(max 250 mg daily); in 2 divided doses increased every 5-7 days to usual dose of 20 -40 mg/kg (max. 1 g daily in 2-3 divided doses

Sodium Valproate

Adult: Initially 600 mg daily in 1-2 divided doses, increased gradually (in steps of 150 300 mg) every 3 days; usual maintenance dose
1-2 g daily ( 20-30 mg /kg daily), max. 2.5 g daily
Child:
- 1month -12 years, initially 10-15 mg/kg (max. 600mg) daily in 1-2 divided doses, usual maintenance dose 25-30 mg/kg
  daily in 2 divided doses

Initiation of valproate treatment by
intravenous administration,

Adult and child over 12 years: initially 10 mg/kg (usually 400 – 800 mg) by intravenous injection (over 3-5 minutes) followed by intravenous infusion or intravenous injection (over 3-5 minutes) in 2-4 divided doses or by continuous intravenous infusion up to max. 2.5 g daily; usual range 1 – 2g daily (20-30 mg/kg daily);
Child
- 1 month -12 years: 10mg/kg by intravenous injection (over 3-5 minutes) in 2-4 divided doses or by continuous intravenous infusion up to usual range 20-40 mg/kg daily
- (For doses above 40 mg/kg daily, monitor clinical chemistry and haematological parameters). Continuation of valproate treatment by intravenous injection (over 3-5 minutes) or intravenous infusion in 2-4 divided doses, or by continuous intravenous infusion, same as established oral daily dose.

Other drugs:

Clonazepam for Myoclonic seizures
Primidone which is metabolized to
Phenobarbitone

Non-drug treatment

Psychotherapy
Health education to patients, relations and public
Discourage harmful cultural practices e.g. burning, mutilation

Notable adverse drug reactions, caution and contraindications

Antiepileptics:

foetal damage if used in pregnancy
Serial measurements of alpha fetoprotein and ultrasound studies are necessary with close monitoring by an obstetrician

Phenytoin:

gingival hypertrophy; may not be the first choice in young children

Phenobarbital:

sedation and mental dullness and may affect school performance
in children

Most antiepileptics:

skin rashes, especially Stevens-Johnson syndrome; exfoliative dermatitis

Introduce drugs singly because of possible interaction between drugs.

Doses must be gradually increased to avoid toxicity and other side effects.

Do not use paraldehyde if it has a brownish colour or the odour of acetic acid.

All antiepileptics must be withdrawn slowly so as not to precipitate status epilepticus.

Prevention

Prompt treatment of fever in children to avoid febrile convulsions
Prevention of head injuries mainly from automobile accidents
Treat diseases of the brain early to avoid poor healing and death of brain cells
Immunization of children against communicable diseases
Address causative factors (see above)
Avoid driving and swimming unattended, and operation of machinery.