complex partial seizure

**Terminology:** "Complex partial seizure" is the older (1981 ILAE) term. The 2017 ILAE classification replaced it with "focal impaired awareness seizure." "Simple partial" became "focal aware seizure." Focal seizures that spread bilaterally are "focal to bilateral tonic-clonic" (formerly secondarily generalized). Boards (especially older question banks) still use the old terms.

**Pathophysiology:** Abnormal, hypersynchronous neuronal discharge starting in one hemisphere. Impaired awareness reflects involvement of limbic or bilateral networks. The most common origin is the mesial temporal lobe (hippocampus, amygdala). Frontal origin is the second most common site.

**Clinical features:** - Aura (a focal aware seizure that precedes): rising epigastric sensation, déjà vu or jamais vu, fear, olfactory hallucinations (unpleasant burning smell), or an odd taste - Impaired awareness: staring, unresponsiveness, behavioral arrest - Automatisms: lip smacking, chewing, picking at clothes, fumbling, repetitive swallowing - Duration: usually 1-2 minutes (typically under 3 minutes) - Postictal confusion or drowsiness (minutes), possible postictal aphasia if the dominant hemisphere is involved, and amnesia for the event - Contrast with absence seizures: absence lasts seconds, has abrupt onset and offset, and has no aura or postictal state

**Etiologies:** - Mesial temporal sclerosis (hippocampal sclerosis), the classic cause of temporal lobe epilepsy, often after prolonged febrile seizures in childhood - Tumors (low-grade gliomas, DNET, ganglioglioma) - Cortical dysplasia and other malformations - Stroke, trauma, and CNS infection (HSV encephalitis, neurocysticercosis) - Vascular malformations - Autoimmune encephalitis (e.g., anti-NMDA, anti-LGI1 in limbic encephalitis)

**Diagnosis:** - EEG: interictal temporal spikes or sharp waves, or ictal rhythmic activity - MRI brain with epilepsy protocol: look for hippocampal atrophy or increased T2/FLAIR signal (mesial temporal sclerosis) and structural lesions - Video-EEG monitoring for refractory cases

**Treatment:** - First-line: carbamazepine, oxcarbazepine, or lamotrigine. Levetiracetam is also widely used. - Carbamazepine side effects: SIADH/hyponatremia, agranulocytosis/aplastic anemia, Stevens-Johnson syndrome (HLA-B*1502 in Asian ancestry), hepatic enzyme induction, and teratogenicity (neural tube defects) - Drug-resistant epilepsy (failure of 2 appropriately chosen drugs): evaluate for surgery. Anterior temporal lobectomy is curative in many patients with mesial temporal sclerosis. Other options are vagus nerve stimulation and responsive neurostimulation. - Safety counseling: driving restrictions, seizure precautions

**High-yield pearls:** - Impaired consciousness is what distinguishes complex (impaired awareness) from simple (aware) focal seizures. - Automatisms plus an aura plus postictal confusion point to temporal lobe origin. - Generalized seizures involve both hemispheres from onset, so they do not have an aura or focal onset. - Status epilepticus: first-line is a benzodiazepine (lorazepam IV), then fosphenytoin, valproate, or levetiracetam.