Aetiology

The causes of status epilepticus are varied. In addition to epilepsy, any neurological insult or systemic abnormality capable of inducing a seizure can theoretically cause status epilepticus.

A common cause of status epilepticus in people with known epilepsy is drug withdrawal due to poor anticonvulsant therapy adherence.[9][10] Other common acute causes in adults with or without epilepsy include hypoxia, stroke, metabolic abnormalities, and alcohol intoxication or withdrawal.[11] Other less common causes are infection, trauma, and tumour.[10]

Pathophysiology

Status epilepticus occurs when mechanisms that abort seizure activity fail. This failure can arise from excessive and abnormally persistent excitation or ineffective inhibition.[12] In animal models, seizure activity lasting >30 minutes was shown to cause cerebral injury, especially in limbic structures such as the hippocampus. This damage is largely due to the accumulation of excitatory neurotransmitters, notably glutamate. Other contributing mechanisms of neuronal injury include hyperthermia, hypoxia, lactic acidosis, and hypoglycaemia.[13]

Classification

A definition and classification of status epilepticus[2]

This classification of status epilepticus is based on the clinical presentation. The two main criteria are:

  • The presence or absence of prominent motor symptoms

  • The degree (qualitative or quantitative) of impaired consciousness.

Status epilepticus (SE) is classified as:

With prominent motor symptoms

  • Convulsive SE

    • Generalised convulsive

    • Focal onset evolving into bilateral convulsive SE

    • Unknown whether focal or generalised

  • Myoclonic SE (prominent epileptic myoclonic jerks)

    • With coma

    • Without coma

  • Focal motor

    • Repeated focal motor seizures (jacksonian)

    • Epilepsia partialis continua

    • Adversive status

    • Oculoclonic status

    • Ictal paresis (i.e., focal inhibitory SE)

  • Tonic status

  • Hyperkinetic SE

Without prominent motor symptoms

  • Non-convulsive SE with coma (including so-called 'subtle' SE)

  • Non-convulsive SE without coma

    • Generalised

      • Typical absence status

      • Atypical absence status

      • Myoclonic absence status

    • Focal

      • Without impairment of consciousness (aura continua, with autonomic, sensory, visual, olfactory, gustatory, emotional/psychic/experiential, or auditory symptoms)

      • Aphasic status

      • With impaired consciousness

    • Unknown whether focal or generalised

      • Autonomic SE

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