Neurology · Status Epilepticus
The facts most likely to be tested
Status epilepticus is defined as a single seizure lasting greater than 5 minutes or two or more seizures without a return to baseline consciousness between events.
The first-line pharmacologic treatment for status epilepticus is an intravenous benzodiazepine, typically lorazepam.
If intravenous access is unavailable, intramuscular midazolam is the preferred first-line agent for rapid seizure termination.
Following benzodiazepine administration, a second-line antiepileptic drug (AED) such as fosphenytoin, levetiracetam, or valproic acid must be administered to prevent seizure recurrence.
Refractory status epilepticus is defined as seizures that persist despite the administration of a benzodiazepine and an appropriate dose of a second-line AED.
The management of refractory status epilepticus requires general anesthesia with agents such as propofol, midazolam, or pentobarbital with continuous EEG monitoring.
Hypoglycemia is a common, reversible cause of seizures, necessitating immediate point-of-care glucose testing and administration of dextrose if indicated.
Vignette unlocked
A 45-year-old male is brought to the emergency department by EMS after a witnessed tonic-clonic seizure that lasted 12 minutes. Upon arrival, the patient remains unresponsive and continues to exhibit rhythmic jerking of the bilateral upper extremities. His blood glucose is 98 mg/dL. The patient has no known history of epilepsy and is not currently taking any medications.
What is the most appropriate next step in the management of this patient?
Intravenous lorazepam
The patient is in status epilepticus, and the first-line treatment is an intravenous benzodiazepine to rapidly terminate the seizure activity.
Full handout
High yield triage
Etiology / Epidemiology
Defined as >5 minutes of continuous seizure activity or recurrent seizures without return to baseline. Common in medication non-compliance or structural brain injury.
Clinical Manifestations
Characterized by tonic-clonic activity or non-convulsive altered mental status. Continuous seizure activity is the hallmark.
Diagnosis
Clinical diagnosis supported by EEG showing rhythmic discharges. Serum glucose and electrolytes are mandatory to rule out metabolic triggers.
Treatment
First-line: Benzodiazepines (e.g., Lorazepam). Respiratory depression is the primary risk. Follow with Fosphenytoin or Levetiracetam.
Prognosis
High mortality if untreated. Excitotoxic neuronal injury occurs after prolonged activity. Monitor for rhabdomyolysis.
Full handout
Epidemiology & Etiology
Status epilepticus is a neurological emergency often triggered by antiepileptic drug withdrawal, metabolic disturbances like hyponatremia, or structural lesions such as stroke or tumor. It occurs across all ages but is most frequent in patients with a known seizure disorder history. Prompt identification is critical to prevent permanent neuronal damage.
Pertinent Anatomy
The cerebral cortex is the primary site of origin for generalized seizures. Prolonged activity leads to excessive metabolic demand in the hippocampus, which is highly susceptible to ischemic injury. Management requires rapid access to the intravenous space for drug delivery.
Pathophysiology
The process involves a failure of inhibitory GABAergic mechanisms and an over-activation of excitatory glutamate receptors. Sustained depolarization leads to intracellular calcium overload, causing neuronal death. If the seizure persists, the brain loses the ability to autoregulate, leading to cerebral edema and systemic complications like hyperthermia.
Clinical Manifestations
Patients present with tonic-clonic movements or subtle non-convulsive signs like eye deviation or rhythmic twitching. Airway compromise and aspiration are immediate threats. Monitor for autonomic instability, including tachycardia and hypertension, which may transition to shock.
Diagnosis
The diagnosis is primarily clinical based on the 5-minute duration threshold. An EEG is the gold standard to confirm non-convulsive status epilepticus in patients who remain comatose after motor activity ceases. Always check fingerstick glucose to rule out hypoglycemia immediately.
Treatment
Administer Lorazepam (IV) as the first-line agent. If IV access is delayed, use Intramuscular Midazolam. Follow immediately with a long-acting agent like Fosphenytoin or Levetiracetam. Do not use phenytoin in patients with heart block due to cardiac arrhythmia risks.
Prognosis
Prognosis depends on the underlying etiology and duration of the seizure. Rhabdomyolysis and acute kidney injury are common systemic complications. Continuous EEG monitoring is required to ensure the cessation of subclinical electrical activity.
Differential Diagnosis
Hypoglycemia: rapid reversal with dextrose
Psychogenic non-epileptic seizures: lack of post-ictal confusion
Syncope: brief duration, no post-ictal state
Drug toxicity: history of overdose or ingestion
Encephalitis: associated with fever and meningeal signs