Seizures
Aetiology
Pathogenesis
Imbalance of NT --> Hyperexcitability
Clinical Features
Infantile Spasms
Juvenile Myoclonic Epilepsy (Janz)
Childhood Absence Epilepsy
Benign Focal Epilepsy of Childhood with Rolandic/Centrotemporal Spikes
Investigations
Management
5-10 min: Supportive care - DRSABC
>10min:
Source
Toronto Notes 2012
www.rch.org.au
- Benign febrile seizure (most common)
- Hypoxic ischemic encephalopathy ("asphyxia'')
- Intracranial hemorrhage, trauma
- Metabolic causes (e.g. hypoglycemia, hypocalcemia, hyponatremia)
- CNS infection
- Idiopathic epilepsy and epileptic syndromes
- Neurocutaneous syndromes
- CNS tumour
- Arteriovenous malformation
- Ingestions/drug withdrawal
- Rule out conditions that mimic seizure:
- Breath holding
- Night terror
- Benign paroxysmal vertigo
- Narcolepsy
- Pseudoseizure
- Syncope
- Tic, myoclonus, tremor
- Hypoglycemia
- TIA
- Benign sleep myoclonus infancy (movement stop when child is woken, up to 3yo)
Pathogenesis
Imbalance of NT --> Hyperexcitability
Clinical Features
- Most convulsions are brief and self limiting, generally ceasing within 5 - 10 minutes
Infantile Spasms
- Onset 4-8 months (NOTHING TO DO WITH IMMUNISATION)
- Brief, repeated symmetric contractions of neck, trunk, extremities (flexion and extension)
- lasting 10-30 sec
- Occur in clusters; often associated with developmental delay
- 20% unknown etiology; may have good response to treatment
- 80% due to metabolic or developmental abnormalities, encephalopathies, or are associated with neurocutaneous syndromes; these have poor response to treatment
- Onset commonly 3-5 yrs of age
- Characterized by triad of 1) multiple seizure types, 2) diffuse cognitive dysfunction and 3) slow generalized spike and slow wave EEG
- Seen with underlying encephalopathy and brain malformations
Juvenile Myoclonic Epilepsy (Janz)
- Adolescent onset (12-16 yrs of age); autosomal dominant with variable penetrance
- Myoclonus particularly in morning; frequently presents as generalized tonic-clonic seizures
Childhood Absence Epilepsy
- Multiple absence seizures per day that may generalize in adolescence or resolve spontaneously
- Peak age of onset 6-7, F>M, strong genetic predisposition
- Each seizure is less than 30 sec, no post-ictal state, may have multiple seizures per day
Benign Focal Epilepsy of Childhood with Rolandic/Centrotemporal Spikes
- Onset peaks at 5-10 yrs of age, 16% of all non-febrile seizures
- Focal motor seizures involving tongue, mouth, face, upper extremity usually occuring in sleepwake transition states
- Remains conscious, but aphasic post-ictally
- Remits spontaneously in adolescence; no sequelae
Investigations
- FBC, UEC, CMP, BSL
- Toxicology screen if indicated
- EEG, CT and LP if indicated
- EEG may be indicated for first-time non-febrile seizure
- EEG/CT not indicated to determine recurrence risk of benign febrile seizures or to determine seizure type or epileptic syndrome
Management
5-10 min: Supportive care - DRSABC
>10min:
- Support airway and breathing, apply oxygen by mask, monitor.
- Secure IV access, check bedside BSL and send urgent specimen for calcium / electrolytes and venous blood gas. If hypoglycaemia present, also see Hypoglycaemia guideline and correct the low sugar. Give benzodiazepine.
- Repeat benzodiazepine after 5 minutes of continuing seizures.
- If convulsion continues for a further 5 - 10 minutes, commence IV phenytoin or phenobarbitone. If IV access cannot be secured and seizures refractory to benzodiazepines, consider IO access.
- Consider pyridoxine (100mg IV) in young infants with seizures refractory to standard anticonvulsants.
- Thiopentone or Propofol and rapid sequence induction (RSI) may be required for seizure control.
- Buccal midazolam can alleviate prolonged seizures
- Absence: Na valproate, ethosuximide
Source
Toronto Notes 2012
www.rch.org.au