Paediatrics chapters
Status epilepticus
A seizure that does not stop, or seizures without recovery in between: the definition, common causes in children, what prolonged seizures do to the body, and the step-by-step emergency treatment.
- Status epilepticus is a seizure lasting 30 minutes or more, or repeated seizures without regaining consciousness in between; it is a medical emergency, commonest under 1 year, often from stopping antiepileptic drugs, fever, infection or metabolic upset.
- First secure airway, breathing, circulation, oxygen and check glucose; give a benzodiazepine (IV diazepam, lorazepam or midazolam; rectal diazepam if no IV), repeated if needed, then IV phenytoin (or fosphenytoin), then phenobarbitone or valproate.
- Refractory status needs ICU, a midazolam or pentobarbital infusion or anaesthesia; outcome depends mainly on the cause, with mortality about 4-5%.
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Overview
Status epilepticus is a neurological emergency. It is defined as a single seizure lasting 30 minutes or more, or a series of seizures without return of consciousness between them. Prolonged seizures injure the brain and the rest of the body, so treatment starts well before 30 minutes have passed: a child who is still fitting on arrival is treated straight away. It may be the first ever seizure in some children.
Types
- Convulsive status: continuous or repeated tonic-clonic activity; the common and dangerous form.
- Non-convulsive status: prolonged absence or complex partial seizures; the child is confused or unresponsive with little movement. Suspect it when a child does not wake as expected after a fit; EEG confirms.
Aetiology
- Most frequent in children under 1 year.
- Akbar names two common causes: sudden withdrawal of antiepileptic drugs and high fever from a non-CNS infection in a child with a static brain injury or seizure disorder.
- Nelson adds: new-onset epilepsy, missed doses, drug intoxication or withdrawal, hypoglycaemia, electrolyte imbalance, head trauma, CNS infection, stroke, haemorrhage, metabolic disorders and hypoxia.
| Age | Common causes |
|---|---|
| Neonates | Hypoxic-ischaemic encephalopathy, infection, inborn errors of metabolism, intraventricular haemorrhage, malformations, pyridoxine deficiency or dependency |
| Infants and children | Febrile status, infection (meningitis, encephalitis), anticonvulsant withdrawal, metabolic upsets, malformations, trauma |
Pathophysiology
- Continuously firing neurons have huge metabolic demands; after about 60 minutes these outstrip supply and neurons die.
- Vulnerable areas: hippocampus, amygdala, cerebellum, cortex and thalamus.
- Brain changes: venous congestion, petechial haemorrhages, cerebral oedema, raised ICP, leaky blood-brain barrier; raised calcium and prostaglandins add to cell death.
- Body changes: hypoxia, lactic acidosis, hyperpyrexia, hypoglycaemia, hyperkalaemia, autonomic failure with hypotension and shock, renal and lung failure.
Fever worsens neuronal discharge and damage, so cooling is part of treatment.
Management
The three goals: keep vital functions going, stop the seizure quickly and safely, and find and treat the cause (for example hypoglycaemia or meningitis).
Step 1: stabilise (first 5-10 minutes)
- Airway: the top priority; position, suction, oral airway; intubate if needed. If vomiting, turn the head to the side.
- Breathing: oxygen, pulse oximetry; ventilate if breathing is poor.
- Circulation: pulse, blood pressure, IV access, fluids if needed, cardiac monitoring.
- Bedside glucose: if low (Akbar: under 50 mg/dl), give 2-4 ml/kg of 25% dextrose (Nelson's general advice is to treat hypoglycaemia at once).
- Temperature: lower a high temperature.
- Bloods: count, glucose, sodium, calcium, magnesium, toxicology, and antiepileptic drug levels if the child is on treatment.
Step 2: drugs
| Stage | Drug | Notes |
|---|---|---|
| First line | Benzodiazepine: diazepam (Nelson 0.2-0.5 mg/kg; Akbar 0.2 mg/kg IV), lorazepam 0.05-0.1 mg/kg, or midazolam 0.1-0.2 mg/kg | Fast onset; diazepam acts briefly (about 20 minutes); may be repeated after 5-10 minutes (Akbar: up to three doses in all); rectal diazepam if no IV line |
| Second line | Phenytoin 20 mg/kg IV (Akbar) or fosphenytoin 10-20 mg/kg phenytoin equivalents (Nelson) | Give in normal saline (precipitates in glucose); never IM; slow infusion (Akbar: about 1 mg/kg/minute); cardiac monitoring for arrhythmia, bradycardia, hypotension |
| Third line | Phenobarbitone 20 mg/kg IV (Nelson 10-20 mg/kg) or valproate 20 mg/kg | Phenobarbitone acts slowly (15-30 minutes); be ready to intubate after a benzodiazepine plus phenobarbitone |
| Refractory | Continuous midazolam or pentobarbital infusion; general anaesthesia | ICU, airway protection, blood pressure support, continuous EEG |
- Akbar also lists rectal paraldehyde (mixed with oil in a glass syringe), rectal valproate and IV lidocaine for resistant cases.
- Allow each drug enough time to act before adding the next, and avoid stacking too many sedatives.
Diazepam stops the fit but wears off fast; follow it with phenytoin, which lasts longer and sedates less, so neurological signs can still be followed.
Phenytoin must not be diluted in dextrose (it precipitates) and must not be given intramuscularly.
"ABC, then Glucose, then Benzo twice, then Phenytoin, then Phenobarbitone, then ICU."
Rectal diazepam technique (Akbar)
Give it undiluted through a small syringe or short catheter about 4 cm into the rectum, then hold the buttocks together for a few minutes so it is not expelled. It can be repeated after 5-10 minutes.
Step 3: after the seizure stops
- Start maintenance treatment with a suitable antiepileptic (for example phenytoin or phenobarbitone, or the child's usual drug restarted).
- Lumbar puncture only when the child is stable and raised ICP is excluded; if sepsis or meningitis is likely, give IV antibiotics without waiting for the tap.
- CT scan for trauma, raised ICP, focal signs, unexplained coma or suspected herniation.
- A febrile child with a first seizure presenting as status may be started on an antiepileptic for a period (Akbar).
A child who stays unresponsive after the jerking stops may be in non-convulsive status; an EEG is needed.
Hypoglycaemia must be checked and corrected before or alongside the first anticonvulsant.
Complications
Hypoxia, lactic acidosis, hyperkalaemia, hypoglycaemia, hyperpyrexia, shock, aspiration, renal and respiratory failure, cerebral oedema, plus drug side effects (respiratory depression, hypotension). Long-term: intellectual disability, behaviour problems, focal deficits and chronic epilepsy, more often in infants.
Prognosis
- Outcome depends mainly on the underlying cause, not on the seizure itself.
- Mortality is rare in idiopathic or febrile status; overall about 4-5% (Nelson), and about 10-15% within months when status is due to an acute symptomatic or progressive brain disease (Akbar).
- Nelson gives about 14% risk of new neurological deficit, again mostly from the cause.
- Further seizures follow in about 30%; another episode of status is less common.
Expect: the 30-minute definition and early treatment; commonest under 1 year; antiepileptic withdrawal and fever as frequent causes; ABC, oxygen and bedside glucose first; benzodiazepine (rectal if no IV) then phenytoin or fosphenytoin then phenobarbitone, then infusion or anaesthesia; phenytoin given in saline, never IM, with cardiac monitoring; respiratory depression with diazepam plus phenobarbitone; outcome depends on the cause.
Quick revision
- Seizure 30 minutes or more, or repeated without recovery; treat early.
- Commonest under 1 year; drug withdrawal, fever, infection, metabolic causes.
- ABC, oxygen, IV access, glucose (25% dextrose if low), cool the child.
- Benzodiazepine, repeat if needed; rectal diazepam if no IV.
- Phenytoin 20 mg/kg in saline (or fosphenytoin), monitored.
- Phenobarbitone or valproate next; then infusion or anaesthesia in ICU.
- LP only when stable; antibiotics first if infection likely.
- Prognosis set by the cause; mortality about 4-5%.
Written by The House Job from standard references (Basis of Paediatrics by Pervez Akbar; Nelson Essentials of Paediatrics).
FAQ
Why not wait 30 minutes before treating?
The longer a seizure lasts the harder it is to stop and the greater the damage, so a child still fitting is treated at once rather than waiting for the definition to be met.
What should be checked before any anticonvulsant?
Airway, breathing and circulation with oxygen, then a bedside blood glucose, because hypoglycaemia is a quick and treatable cause.
Why is phenytoin preferred after diazepam rather than phenobarbitone?
It lasts longer than diazepam, sedates less so neurological signs can be followed, and causes less respiratory depression than combining phenobarbitone with a benzodiazepine.
Can a lumbar puncture be done straight away?
No. It waits until the child is stable and raised pressure is excluded. If meningitis is suspected, antibiotics are given first.