Differential Diagnosis for PNES vs Epilepsy

When differentiating Psychogenic Non-Epileptic Seizures (PNES) from epilepsy on physical exam or during a spell, consider the following categories:

• Single Most Likely Diagnosis
  • Epilepsy: This is often the first consideration due to the presentation of seizures. However, the diagnosis of epilepsy requires evidence of epileptiform activity on EEG, which may not be present during a physical exam or a single spell.
• Other Likely Diagnoses
  • PNES: These are episodes that resemble epileptic seizures but are not caused by abnormal electrical activity in the brain. They are psychological in origin and can be triggered by stress, trauma, or emotional distress. Characteristics such as asynchronous movements, side-to-side head movements, and a fluctuating course can suggest PNES.
  • Syncope: A fainting spell can sometimes be mistaken for a seizure. It is characterized by a brief loss of consciousness, usually triggered by a specific event, and the individual typically regains consciousness quickly.
  • Migraine: Certain types of migraines, especially those with aura, can mimic seizure activity, including visual disturbances and transient neurological symptoms.
• Do Not Miss Diagnoses
  • Status Epilepticus: A life-threatening condition where the brain is in a state of persistent seizure that lasts more than 5 minutes or when a person has recurrent seizures without regaining full consciousness between seizures. Immediate recognition and treatment are crucial.
  • Stroke or TIA (Transient Ischemic Attack): Although less common, stroke or TIA can present with sudden onset of neurological deficits that might be confused with seizure activity. Prompt diagnosis is critical due to the need for urgent intervention.
• Rare Diagnoses
  • Narcolepsy: Characterized by sudden sleep attacks, cataplexy, and other symptoms that could be mistaken for seizures in some cases.
  • Hyperekplexia: A rare genetic disorder that affects the brain's startle response, leading to an exaggerated startle reaction that might resemble a seizure.
  • Nonepileptic myoclonus: Sudden, brief jerks or twitches that are not due to epilepsy but can be confused with myoclonic seizures.

Each diagnosis has distinct features that can guide differentiation during a physical exam or observation of a spell. A thorough history, physical examination, and diagnostic tests such as EEG are essential for an accurate diagnosis.