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.