Focal Aware Seizure

Also written as Simple partial seizure, Focal aware seizure.

Focal aware seizures are brief episodes of motor, sensory, autonomic or psychic phenomena without loss of consciousness. They often herald structural brain disease and require targeted investigation in low‑resource settings.

Definition and diagnosis

A focal aware seizure is a seizure that starts in one cerebral hemisphere and does not impair awareness. Diagnosis is clinical, based on a stereotyped event described by the child or caregiver.

• Detailed seizure history: What was the exact sequence of symptoms? – Confirms focal onset and preserved awareness, distinguishes from generalized seizures
• Witnessed video (if possible): What does the video show? – Provides objective evidence of motor signs and helps localise the focus

• Event lasts seconds to minutes
• No post‑ictal confusion
• Phenomena may be motor (e.g., jerks), sensory (e.g., tingling), autonomic (e.g., flushing) or psychic (e.g., déjà vu)

Severity and staging

Severity is judged by frequency, duration, impact on development and presence of secondary generalisation.

• Mild: isolated events, no impairment
• Moderate: frequent (≥1/week) or brief impairment of school performance
• Severe: daily events, secondary generalisation, or progressive neurological deficit

Causes, most likely first

In low‑resource African settings, structural lesions are the commonest trigger; infections and metabolic disturbances are also frequent.

• Congenital brain malformations (e.g., cortical dysplasia)
• Post‑infectious scarring (cerebral malaria, neurocysticercosis, tuberculous meningitis)
• Perinatal hypoxic‑ischemic injury
• Traumatic brain injury
• Metabolic derangements (hypoglycaemia, hyponatraemia)
• HIV‑related opportunistic lesions

How it presents

Children may describe or be observed having brief, repetitive movements, tingling, visual flashes or strange smells while remaining fully alert.

• Motor: rhythmic jerks of a hand or face
• Sensory: unilateral numbness or tingling
• Autonomic: flushing, pallor, gastric upset
• Psychic: déjà vu, fear, auditory hallucination

Investigations

Goal: identify an underlying structural or metabolic cause; choose tests that are feasible locally.

• Neuroimaging (CT head, MRI if available): What structural abnormality is present? – Detects lesions such as calcified cysticerci, tuberculoma, infarct; if unavailable, refer for imaging when possible
• Basic metabolic panel (glucose, electrolytes, calcium): Are there reversible metabolic triggers? – Abnormalities guide immediate correction
• HIV test (if risk factors present): Is HIV infection contributing? – Positive result prompts evaluation for opportunistic CNS lesions
• Serology for malaria, cysticercosis, TB (where endemic): Is an infectious cause likely? – Positive serology supports targeted antimicrobial therapy

Red flags and complications

Certain features suggest imminent danger or need for urgent referral.

• Secondary generalisation
• Progressive neurological deficit (weakness, visual loss)
• Altered consciousness after an event
• Signs of raised intracranial pressure (vomiting, papilledema)
• Severe metabolic derangement

Management

Treat the underlying cause first; then use antiseizure medication (ASM) only if seizures are frequent or disabling.

• Correct metabolic abnormalities promptly
• Treat infections (e.g., antimalarials, anti‑TB drugs, praziquantel for cysticercosis)
• First‑line ASM in children: carbamazepine or levetiracetam – chosen for efficacy in focal seizures and relatively safe profile
• Avoid phenobarbital as monotherapy in focal seizures due to lower efficacy and sedation
• Monitor for drug interactions (e.g., carbamazepine with antiretrovirals)

Follow‑up and prevention

Regular review to assess seizure control, growth, and drug tolerance; educate families on trigger avoidance.

• Clinic review every 3–6 months
• Repeat imaging if seizures recur or new deficits appear
• Vaccination and malaria prophylaxis to reduce infection‑related triggers
• Counselling on safe sleep position and injury prevention

Often confused with

Conditions that can mimic focal aware seizures.

• Benign paroxysmal movement disorders (e.g., infantile spasms, dyskinesias)
• Psychogenic nonepileptic events
• Migraine aura
• Transient ischemic attack (rare in children)

Where results can mislead

Pitfalls in interpretation that may mask the true diagnosis.

• Normal CT does not exclude small cortical dysplasia – MRI is superior
• Negative malaria smear does not rule out cerebral malaria if clinical picture fits
• Transient electrolyte shifts may normalise after the seizure, hiding the trigger

Questions an examiner may ask

• A 7‑year‑old presents with brief left‑hand jerks while remaining alert – what is your immediate diagnostic priority? — Obtain a focused seizure history and arrange neuroimaging to look for a focal lesion.
• How does a focal aware seizure differ from a focal impaired‑awareness seizure? — The former preserves consciousness; the latter includes altered awareness or post‑ictal confusion.
• A child with frequent focal seizures has a normal CT scan – what is your next step? — Request MRI if available; if not, refer for specialist imaging while treating any reversible metabolic cause.
• Why is carbamazepine preferred over phenobarbital for focal seizures in children? — Carbamazepine has higher efficacy for focal onset and fewer sedative side‑effects; phenobarbital is less effective and can worsen cognition.
• What red‑flag feature would prompt urgent referral to a tertiary centre? — Development of secondary generalisation or new focal neurological deficit.
• A child with focal seizures lives in a malaria‑endemic area; what infection should you specifically screen for? — Cerebral malaria and neurocysticercosis; obtain malaria smear and cysticercosis serology.
• Explain why correcting hypoglycaemia can stop focal seizures. — Low glucose reduces neuronal excitability thresholds, precipitating focal discharges; normalising glucose removes the trigger.
• What distinguishes a psychogenic nonepileptic event from a focal aware seizure? — Lack of stereotyped EEG changes, variable presentation, and often associated psychosocial stressors.

When to seek help

• Secondary generalisation
• New focal neurological deficit
• Persistent altered consciousness
• Signs of raised intracranial pressure

Quick questions

Why are simple partial seizures called focal aware seizures now?

The term reflects that awareness is preserved and aligns with the ILAE classification.

Can a child have focal seizures without any imaging abnormality?

Yes; early cortical dysplasia or functional abnormalities may be invisible on CT, requiring MRI or EEG for detection.

When should I start antiseizure medication?

If seizures are frequent (≥1/week), cause injury, or impair learning, or if a structural lesion is identified that carries recurrence risk.