Seizure disorders
Also known as: epilepsy
Seizure disorders are neurological conditions marked by seizures — sudden episodes of abnormal, excessive electrical activity in the brain. Epilepsy is diagnosed when seizures are recurrent and unprovoked.
A seizure is a sudden burst of abnormal, excessive, synchronized electrical activity in the brain's neurons. Depending on where the discharge begins and how far it spreads, a seizure can cause convulsions, staring spells, unusual sensations, or loss of awareness. Seizure disorders are the conditions in which such episodes occur, and epilepsy is defined by recurrent seizures that are unprovoked — not explained by a temporary insult such as fever, low blood sugar, alcohol withdrawal, or acute head injury.
Seizures are classified by onset. Focal seizures begin in one region of one hemisphere; awareness may be preserved (focal aware) or impaired (focal impaired awareness), and a focal seizure can spread to become generalized. Generalized seizures involve both hemispheres from the start. Generalized types include tonic-clonic seizures (stiffening then rhythmic jerking, with loss of consciousness), absence seizures (brief staring spells common in children), and myoclonic, atonic, tonic, and clonic forms.
Diagnosis rests on the clinical description, electroencephalography (EEG) to capture abnormal discharges, and imaging to look for structural causes such as scarring, tumors, or vascular lesions. Many seizures end on their own within a couple of minutes; status epilepticus — prolonged or back-to-back seizures without recovery — is a medical emergency. Long-term management centers on antiseizure medications, with attention to triggers such as sleep deprivation and missed doses.
The USMLE Step 1 exam tests seizure classification, distinguishing focal from generalized onset, and recognizing status epilepticus. The CCMA exam covers seizure disorders from the medical assisting perspective, including recognizing seizure activity and supporting patient safety during and after an episode.
Key takeaways
- A seizure is abnormal, excessive, synchronized neuronal firing; epilepsy means recurrent unprovoked seizures.
- Focal seizures start in one hemisphere; generalized seizures involve both from onset.
- Generalized types include tonic-clonic, absence, myoclonic, and atonic seizures.
- EEG and neuroimaging support diagnosis; status epilepticus is a medical emergency.
- The USMLE Step 1 tests classification and pathophysiology; the CCMA tests recognition and patient safety.