- A prolonged seizure lasting 5–15 minutes
- Continuous or multiple seizures without intervening periods of consciousness
A prolonged seizure lasting more than 5 minutes, or multiple seizure episodes without intervening periods of consciousness defines status epilepticus. Search carefully for seizure activity in the comatose patient. Manifestations may be subtle (eg, deviation of head or eyes; repetitive jerking of fingers, hands, or one side of the face).
Insert a nasopharyngeal airway. Administer 100% oxygen by nasal cannula or non-rebreathing face mask and monitor with pulse oximetry. Prepare for possible endotracheal intubation in the event that anticonvulsants fail to terminate the seizure.
Insert an Intravenous Catheter
Obtain blood specimens for glucose, electrolytes, magnesium, and calcium determinations; hepatic and renal function tests; and complete blood count; as well as 3–4 tubes of blood for possible toxicology screen or determination of drug levels (including anticonvulsants if patient is known or suspected to be taking them).
Obtain a bedside glucose and give glucose, 50 mL of 50% solution IV if the patient is hypoglycemic. Note: If malnutrition is suspected, give thiamine, 100 mg IV, slowly prior to, or at the same time as, glucose.
Pharmacological Treatment Protocol
Give lorazepam, 2–4 mg (0.05–0.1 mg/kg) IV every 3–4 minutes to 8 mg total in adults and an additional dose of 0.05 mg/kg can be given in children. Diazepam, 5–10 mg (0.25 mg/kg) IV every 3–4 minutes up to 30 mg total dose in adults and 5 mg in children. These drugs have been shown to be equally effective as first-line choices. Lorazepam has a longer duration of action compared to diazepam. Because of this property, lorazepam is currently considered the drug of choice. If venous access cannot be obtained, diazepam can be given rectally, endotracheally, or intraosseously, or midazolam, 0.2 mg/kg, can be given intramuscularly.
If the seizure persists after adequate doses of benzodiazopines, give phenytoin 20 mg/kg by IV infusion at a rate of 50 mg/min or slower. If the seizure persists, an additional 10 mg /kg is given. Infusion of phenytoin at more rapid rates (especially if given into centrally placed IV lines) can precipitate cardiac arrhythmias or hypotension. These unwanted hemodynamic and cardiac side effects can be avoided by the use of fosphenytoin, a prodrug of phenytoin. Fosphenytoin dosages are expressed as phenytoin equivalents (PE). Advantages of fosphenytoin are that it can be administered faster than phenytoin (150 PE/min) and be given intramuscularly if needed. The standard dose is 20 mg PE/kg IV.
Refractory Status Eepilepticus
There is no accepted standard definition of refractory status epilepticus (RSE). A seizure that continues after the administration of first and second-line treatment within 60 minutes of onset of status is considered RSE. An alternate definition is a seizure that is refractory to loading or protracted maintenance doses of at least three anti-epileptics. Consider one of the following pharmacologic agents for patients with RSE. Intubation will most likely be required for all except valproate and levetiracetam. Continuous EEG monitoring should be considered while using these agents.
Administer phenobarbital at a dose of 10–20 mg/kg. Beware of both hypotension and respiratory depression. Endotracheal intubation is often necessary.
Administer midazolam in a loading dose of 0.2 mg/kg followed by an infusion of 0.1–0.4 mg/kg/h. Hypotension is rare compared to propofol.
Propofol, a short-acting nonbarbiturate sedative hypnotic is given at a dose of 1–2 mg/kg load followed by an infusion of 6–12 mg/kg/h. Some evidence exists to show that propofol is superior to midazolam and the shorter acting barbiturates to terminate RSE.
Successful termination of RSE has been reported with valproic acid administration. Give a loading dose of 20–25 mg/kg IV followed by an infusion of 2 mg/kg/h. The chief advantage of this agent is the excellent safety profile and the ease of administration. Intubation may be avoided when using this agent.
RSE has shown to be effective in RSE. Give a dose of 500–2000 mg over 30–60 minutes. The drug has attractive features for RSE with almost no drug interactions, rare allergic reactions and minimal respiratory and cardiovascular effects with IV dosing.
Pentobarbital given at a loading dose of 12 mg/kg followed by and infusion of 5 mg/kg/h titrated up to burst suppression on EEG. Hypotension and myocardial depression are prominent side effects.
Measure Arterial Blood Gases and pH
Arterial blood Pco2 is a sensitive indicator of the adequacy of ventilation (hypercapnia is present in proportion to the degree of hypoventilation). Metabolic acidosis due to lactic acidosis resulting from status epilepticus is commonly present for as long as 1 hour after a seizure. This acidosis requires no treatment. Acidosis lasting longer than 1 hour should prompt a search for other causes (Chapter 44).
Patients in status epilepticus or those given anticonvulsant medications that are strong respiratory depressants may require endotracheal intubation to protect the airway and maintain adequate ventilation. Monitor arterial blood gas measurements to assess adequacy of oxygenation and ventilation.
Perform lumbar puncture immediately to rule out meningitis if fever (body temperature > 38.5°C [>101.2°F]) or nuchal rigidity is present. However, the muscle activity of status epilepticus alone produces transient fever higher than 38.5°C (>101.2°F) in up to 79% of patients. Hyperthermia should be treated with passive cooling measures. Status epilepticus may also produce a mild transient cerebrospinal fluid pleocytosis.
Search for the Underlying Cause of Seizure
Common causes of seizures of acute onset are listed in Table 19–1.
Table 19–1. Common Causes of Seizures of Acute Onset. ||Download (.pdf)
Table 19–1. Common Causes of Seizures of Acute Onset.
|Primary central nervous system disorders idiopathic epilepsy||Onset uncommon after age 25|
|Head trauma||Especially acute trauma or when associated with depressed skull fracture or subdural hematoma|
|Stroke||Especially hemorrhagic stroke|
|Central nervous system mass lesion||Primary or metastatic tumor; brain abscess; arteriovenous malformation|
|Metabolicor systemic disorders cerebral hypoperfusion (hypoxia)||Cardiopulmonary arrest; cardiac dysrhythmia; severe hypotension, etc (Chapters 7, 9, 34).|
|Meningitis, encephalitis||Acute or chronic; bacterial, viral, fungal, parasitic, etc (Chapter 40)|
|Hyponatremia||Serum sodium usually less than 120 mEq/L and often less than 110 mEq/L (Chapter 42)|
|Hypoglycemia||Serum glucose usually less than 40 mg/dL (Chapter 41)|
|Hyperosmolality||Serum osmolality usually greater than 300 mOsm/L (Chapter 42)|
|Hypertensive encephalopathy||Blood pressure usually greater than 250/150 mm Hg; seizures may occur at lower pressures (usually > 160/100 mm Hg) when hypertension occurs suddenly (eg, in children with acute renal failure) (Chapter 34)|
|Hepatic encephalopathy||Respiratory alkalosis nearly always present|
|Eclamptogenic toxemia||Develop and utilize a protocol for managing pregnancy-related seizures|
|Acute drug overdose||Especially with tricyclic antidepressants, theophylline (aminophylline), phencyclidine (PCP), lidocaine, phenothiazines, isoniazid (Chapter 45)|
|Acute drug withdrawal||Anticonvulsants, ethanol, or sedative-hypnotic drugs (with habituation to daily doses of 600–800 mg secobarbital or its equivalent)|
|Benign febrile convulsions of childhood||Do not occur after age 5; always consider other causes|
|Hyperthermia||Internal body temperature usually above 41–42°C (105.8–107.6°F); immediate reduction of body temperature to 39°C (102.2°F) is mandatory (Chapter 44)|
Prevent injury to the patient during the seizure by padding the environment. Do not use rigid restraint (fractures may result) or insert objects into the patient's mouth during the seizure.
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