Panayiotopoulos Syndrome

Panayiotopoulos Syndrome (PS), now classified by the ILAE as a self-limited focal epilepsy with autonomic seizures, is one of the most common epilepsy syndromes in childhood. The ILAE’s reclassification of “benign” to “self-limited” emphasises that while the epilepsy resolves, the seizures can be quite distressing to the child and family.

Presentation and Clinical Features

• Age and Demographics: PS has a broad age range of onset, from 1 to 14 years, with a peak incidence around 3-6 years. It affects both boys and girls.

• Seizure Semiology: Seizures are characterised by a prominent autonomic phase at onset, which is its key distinguishing feature.

  • Initial Symptoms: The most frequent initial symptoms are emesis (vomiting) and nausea, often accompanied by pallor, flushing, and sweating. These are the result of seizure activity in brain regions controlling autonomic functions.

  • Progression: The seizure typically progresses from the initial autonomic symptoms to behavioural changes, such as unresponsiveness, and then to oculomotor deviation (eyes turning to one side). This is often followed by a focal clonic jerk on one side of the body or a generalised tonic-clonic seizure.

  • Duration and Timing: Seizures are typically long-lasting, ranging from 5 to 30 minutes, and can sometimes progress to status epilepticus. Over 90% of seizures occur during sleep, which can be alarming for parents.

  • Frequency: Seizures are usually infrequent, with most children experiencing fewer than 5-6 seizures in their lifetime.

• Development: Neurocognitive development is typically normal. The long duration of seizures can cause parental anxiety, but they don’t lead to long-term cognitive deficits.

• ILAE Classification: The ILAE recognises PS as a unique focal epilepsy, distinct from other syndromes like Rolandic epilepsy. It is now categorised under “Self-Limited Focal Epilepsies of Childhood” in the 2017 classification.

Investigation

• Diagnosis: The diagnosis is primarily clinical, based on the characteristic semiology of the seizures, especially the prominent autonomic features and nocturnal occurrence.

• EEG: The EEG is crucial and nearly always shows focal high-amplitude spikes, typically located in the occipital region but can also be multifocal or shift location between EEGs. These spikes are characteristically activated by and most abundant during sleep.

• Neuroimaging: Routine brain MRI is not recommended for a typical presentation of PS. The brain structure is normal. MRI should be reserved for atypical cases where a structural lesion is suspected.

Management

• Prognosis: The prognosis for PS is excellent. The condition is self-limited, and seizures almost always resolve spontaneously within 1-2 years of onset, usually before age 12.

• Treatment Decision: The decision to treat is a shared one between the clinician and family. Given the infrequent seizures and self-limited nature, the preferred management strategy is often no treatment.

• Indications for Treatment: Medication is considered if seizures are frequent, particularly long-lasting, or if a child experiences multiple seizures in a short period (cluster).

• First-Line Medications: Levetiracetam is an excellent choice due to its broad spectrum and good tolerability. Other effective options include Carbamazepine and Lamotrigine.

• Medications to Avoid: While not contraindicated, older AEDs like phenytoin and phenobarbital are generally avoided due to their side effect profiles.