Focal seizures
Types
- Focal seizure with preserved awareness
- Focal seizure with impaired awareness
Can occur individually or one can lead to other
Can also lead to secondary generalization
Focal seizure with preserved awareness
- can be
- sensory in form of aura - focal aware seizure
- motor seizure
- there can be motor march from face to arm to leg Jacksonian march
- can be post ictal paralysis Todd's palsy that can last for minutes to hours or longer
Focal seizure with impaired awareness
- lasts for 1-2 mins
- preceded by aura like raised abdominal feeling or déjà vu, sensory hallucinations
- micropsia and macropsia - temporal lobe
- difficult to characterize sensations - frontal lobe
- focal sensations - partial lobe
- simple visual experiences - occipital lobe
- Automatisms - automatic semipurposeful movements of mouth, extremities
- frontal lobe seizures are more common in night
- can have salivation, dilation of pupils and flushing
- appears to interact, but consciousness impaired
- contralateral dystonic posture of arm
- can also have Todd's palsy or aphasia
Focal to bilateral tonic-clonic seizures (2⁰ generalization)
- often eye and head deviation to the contralateral side
- tongue biting, urinary incontinence, vomiting, cyanosis, risk of aspiration
- seizure last for 1–2 mins
- figure of 4 arm, Statue of Liberty posture are common
- EEG shows focal spikes or sharp waves in the region where seizure originates
- Sleep deprived EEG is preferred
- MRI is superior to CT
Syndromes
Benign epilepsy with focal seizures
| Name | Age | Features |
|---|---|---|
| Benign childhood epilepsy with centrotemporal spikes (BECTS) | 3 to 10 years | - child typically wakes up at night due to seizure - buccal and throat tingling - tonic contraction on one side of face with drooling and inability to speak - secondary generalization can also occur - MRI normal - responds well to Oxcarbazepine and carbamazepine |
| Atypical BECTS | younger age group | - multiple seizures - drop attacks - developmental delays - bilateral asynchrony |
| Benign epilepsy with occipital spikes (panayoipoulous type) |
early childhood | - imapired awareness and ictal vomiting |
| (gastaut type) | late childhood | - imapired awareness - visual aura - migranes (occurs independently of seizure - epilepsy migrane sequence) |
| benign infantile familial convulsive syndromes | with gene mutations | |
| benign infantile non-familial syndromes | - impaired awareness - 2⁰ generalization - mild gastroenteritis |
|
| Nocturanal autosomal dominant frontal epilepsy | - acetylcholine receptor and KCNT1 gene mutation - nocturnal seizure - dystonic posture - screaming, agitation, kicking - responds well to carbamazepine |
severe epilepsy syndromes with focal seizures
- most commonly have brain lesions
- drug resistant epilepsy - can be metabolic seizure
- brain malformations can cause focal seizures include focal cortical dysplasia, struge weber, hemimegalencephaly, dysembryonoplastic neuroepithelial tumors
| name | Age | features |
|---|---|---|
| epilepsy of infancy with migrating focal seizure | infancy | - secondary to mutation in calcium sensitive potassium channels (KCNT) - mutifocal sever parital seizures - progressive mental retardation |
| pseudo Lennox Gastaut syndrome | - secondary generalizations in the form of absent seizures - drop attacks |
|
| mesial temporal lobe sclerosis | - preceded by febrile seizures - atropy, dysplasia and gliosis of hippocampus, or rarely amygdala - SUCO gene - most common cause of surgically remidiable epilepsy |
|
| Landau Kleffner epilepsy aphasia syndrome | - temporal discharges in sleep - loss of speech and verbal auditory agnosis |
|
| syndrome of continuous spike wave in slow wave sleep | - global delay - >85% of slow wave sleep recording dominated by epileptiform discharges |
|
| Rasmussen encephalitis | - occurs in unilateral intractable partial seizure - epileptia partialis continua, progressive hemiparesis of affected side - progressive atrophy of contalateral hemisphere - autoimmune etiology has been hypothesised |