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Emergency and Acute Medicine - Seizure (Adult)
Overview
A seizure is a transient episode of abnormal, excessive neuronal activity in the brain, leading to changes in consciousness, behavior, sensation, or motor activity. Seizures are broadly classified into generalized and partial (focal) types. Generalized seizures typically involve both hemispheres and often present as tonic–clonic (grand mal) activity, beginning with myoclonic jerks followed by loss of consciousness and sustained muscle contractions. Nonconvulsive generalized seizures, such as absence seizures, manifest as brief alterations in awareness without major motor activity. Partial seizures may be simple (without loss of consciousness) or complex (with impaired consciousness and features such as confusion, automatisms, or hallucinations).
Status epilepticus is a life-threatening emergency defined as a seizure lasting more than 5–10 minutes or recurrent seizures without recovery between episodes. It carries a mortality rate of approximately 10–12%. Notably, many patients presenting with status epilepticus have no prior history of seizures. Alcohol withdrawal seizures typically occur within 24 hours of cessation and rarely progress to status. A single seizure carries about a 35% risk of recurrence within five years.
Etiology
Seizures may result from a wide range of causes. Common etiologies include hypoxia, hypertensive encephalopathy, and eclampsia. Infectious causes include meningitis, encephalitis, and brain abscess. Vascular causes such as ischemic or hemorrhagic stroke, subarachnoid hemorrhage, and intracranial hematomas are important considerations. Structural abnormalities include brain tumors, prior trauma, or degenerative diseases such as multiple sclerosis. Metabolic disturbances such as hypoglycemia, hyperglycemia, hyponatremia, hypernatremia, and hypocalcemia are frequent reversible causes.
Toxins and drugs are also significant contributors, including cocaine, tricyclic antidepressants, salicylates, and withdrawal states (alcohol or benzodiazepines). Other causes include congenital abnormalities, idiopathic epilepsy, and trauma.
Clinical Features
Patients typically present with an abrupt onset of altered consciousness and involuntary motor activity, including tonic stiffening or clonic jerking. Some patients experience an aura preceding focal seizures. Seizures usually last 90–120 seconds and are followed by a postictal state, characterized by confusion, somnolence, and temporary memory impairment.
Signs suggesting recent seizure activity include intraoral injuries, urinary incontinence, and transient focal deficits such as Todd paralysis. Additional findings may point to the underlying cause, such as fever and neck stiffness in central nervous system infections, needle marks in substance abuse, or focal neurologic deficits in structural brain lesions.
Evaluation
A detailed history, especially from witnesses, is critical. Important elements include prior seizure history, medication compliance, recent illness, trauma, and substance use. Physical examination should include a complete neurologic assessment and evaluation for trauma.
In patients with known epilepsy and a typical presentation, minimal testing such as serum glucose and anticonvulsant levels may suffice. However, new-onset seizures require a full workup, including electrolytes, calcium, toxicology screening, and neuroimaging (typically noncontrast CT). Lumbar puncture is indicated in patients with fever, suspected infection, immunocompromise, or persistent altered mental status. MRI may be arranged later for more detailed evaluation. EEG is useful, particularly in suspected nonconvulsive status epilepticus.
Management
Initial management focuses on airway, breathing, and circulation (ABCs). Oxygen, suction, and airway protection are essential, with rapid-sequence intubation if the patient cannot protect the airway. Intravenous access should be established, and serum glucose checked immediately; hypoglycemia should be treated with IV dextrose.
Active seizures are treated promptly with benzodiazepines such as lorazepam or diazepam, which are first-line agents. If seizures persist, second-line agents include fosphenytoin, levetiracetam, phenobarbital, or valproate. Refractory cases may require propofol infusion and intensive care management. Naloxone should be administered if opioid overdose is suspected.
Management also depends on the clinical scenario. First-time seizures with normal evaluation and return to baseline may be discharged with close follow-up. Patients with structural lesions, recurrent seizures, or subtherapeutic antiepileptic drug levels require initiation or adjustment of therapy in consultation with neurology. In pregnant patients, eclampsia must be considered and treated with magnesium and obstetric consultation. Alcohol withdrawal seizures are treated with benzodiazepines.
Disposition and Follow-Up
Patients with status epilepticus, underlying serious conditions (e.g., meningitis, intracranial lesions), or recurrent uncontrolled seizures require hospital admission, often to the ICU. Patients with uncomplicated seizures, normal evaluation, and reliable follow-up may be discharged. Driving restrictions should be advised until seizures are controlled.
Key Points
The most common cause of recurrent seizures is subtherapeutic anticonvulsant levels. Benzodiazepines are the first-line treatment for acute seizures. Any seizure lasting longer than 5–10 minutes should be treated as status epilepticus. Identifying and treating the underlying cause is essential for long-term management.
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