Summary

Focal seizures originate from a localised area of the brain (usually one hemisphere). They were previously called "partial seizures." The clinical features depend on the cortical region involved — temporal lobe seizures are the most common type. Focal seizures may occur with preserved awareness (focal aware seizures, formerly "simple partial") or impaired awareness (focal impaired awareness seizures, formerly "complex partial"). They may also secondarily generalise into a tonic-clonic seizure. Temporal lobe seizures classically present with an aura (epigastric rising, déjà vu, olfactory hallucinations) followed by automatisms (lip smacking, plucking at clothes). MRI brain and EEG are essential investigations. First-line treatment is carbamazepine or lamotrigine.

Key Facts

• Origin: One hemisphere; Focal cortical area
• Awareness:
  • Focal aware (simple partial) — consciousness preserved
  • Focal impaired awareness (complex partial) — consciousness impaired
• Temporal lobe = Commonest; Aura + automatisms
• Frontal lobe = Motor features; Bizarre automatisms
• Investigations: MRI brain; EEG
• Treatment: Carbamazepine or Lamotrigine (first-line)

Clinical Pearls

"The Aura IS the Seizure": The aura (e.g., epigastric rising, déjà vu) is not a warning — it is the seizure beginning. It localises the focus.

"Temporal Lobe = Lip Smacking + Memory Symptoms": Automatisms (lip smacking, plucking at clothes) and altered memory (déjà vu, jamais vu) are classic for temporal lobe origin.

"Frontal Lobe = Bizarre Motor Behaviour": Frontal seizures cause unusual movements (bicycling legs, sexual automatisms) and can be mistaken for psychiatric events.

"Focal Can Generalise": Focal onset seizures can spread to become bilateral tonic-clonic (secondary generalisation). Identifying the focal onset is important for treatment.

Why This Matters Clinically

Focal seizures indicate a localised brain abnormality. Imaging is essential to exclude structural lesions (tumour, hippocampal sclerosis). First-line AEDs for focal epilepsy differ from those for generalised epilepsy.[1,2]

Inter-ictal Examination

• Often normal
• Look for underlying cause:
  • Focal neurological signs (stroke, tumour)
  • Skin stigmata (Tuberous sclerosis — shagreen patch, adenoma sebaceum)

During Seizure (Witness Description)

Key Guidelines

What is a focal seizure?

A focal seizure starts in one part of the brain. This is different from seizures that affect the whole brain at once. You might stay aware during it, or you might become confused or unaware.

What are the symptoms?

• Strange feelings like déjà vu or a rising sensation in your stomach
• Unusual smells or tastes
• Staring, lip smacking, or repetitive movements
• Sometimes it spreads and causes a full body shaking seizure

How is it treated?

• Medication: Tablets like carbamazepine or lamotrigine stop most seizures
• Investigations: A brain scan (MRI) and brainwave test (EEG) help find the cause
• Surgery: For some people, an operation can remove the part of the brain causing seizures

High-Yield Exam Topics

Sample Viva Question

Q: A patient describes a rising sensation from the stomach followed by staring and lip smacking. What is the diagnosis and management?

Model Answer: This is a focal impaired awareness seizure (formerly complex partial), most likely temporal lobe epilepsy. The epigastric aura and oro-alimentary automatisms (lip smacking) are classic for mesial temporal origin.

Investigations:

• MRI Brain: Look for hippocampal sclerosis (mesial temporal sclerosis) or tumour
• EEG: Interictal temporal lobe spikes

Management:

• First-line: Carbamazepine or Lamotrigine
• If drug-resistant (failed ≥2 ASMs), refer for epilepsy surgery workup — temporal lobectomy can be curative (70% seizure-free)

Driving: Must be seizure-free before driving (check DVLA rules).

Last Reviewed: 2025-12-24 | MedVellum Editorial Team