20: Status Epilepticus

CONVULSIVE STATUS EPILEPTICUS

GENERAL CONSIDERATIONS

A seizure that lasts longer than 5 minutes, or multiple seizure episodes with no intervening periods of consciousness is the current accepted definition of status epilepticus. Observe carefully for seizure activity in the patient in coma. Signs of convulsive status epilepticus (CSE) may be subtle (deviation of head or eyes; repetitive jerking of fingers, hands, or one side of the face).

PROTECT THE AIRWAY

Use a nasopharyngeal airway. Administer 100% oxygen by nasal cannula or non-rebreathing face mask and monitor with pulse oximetry. Be prepared for possible endotracheal intubation if anticonvulsants therapy fails to terminate the seizure or causes respiratory depression after seizure termination (see Chapter 9).

INSERT AN INTRAVENOUS CATHETER

Obtain blood specimens for glucose, electrolytes, magnesium, and phosphate determinations; hepatic and renal function tests; and complete blood count; as well as additional tubes of blood for possible toxicology screen or measurement of anticonvulsant levels if the patient is known or suspected to be on these medications. Consider blood and urine cultures as needed based on the presentation.

RULE OUT HYPOGLYCEMIA

Obtain bedside glucose and administer 2.5 mL/kg of 10% dextrose solution if the patient is hypoglycemic. If an intravenous (IV) line cannot be established, hypoglycemia can be treated with glucagon, given intramuscularly or subcutaneously at a dose of 0.03 mg/kg, maximum of 1 mg.

PHARMACOLOGICAL TREATMENT PROTOCOL

First-line Agent

Benzodiazepines

Administer lorazepam, 0.1 mg/kg IV (max dose 5 mg) over 1 minute. Repeat lorazepam dose in 5 minutes if the seizure has not terminated. Diazepam 0.2 mg/kg is an alternative. The two drugs have been shown to be equally effective as first-line choices. Lorazepam has a longer duration of action compared with diazepam. Because of this property, lorazepam is currently considered the drug of choice. If venous access cannot be obtained, midazolam, 0.2 mg/kg, can be administered by several routes: intramuscularly, intranasal, or buccal. Alternatively, diazepam can be given rectally 0.2-0.5 mg/kg (Figure 20–1).

Second-line Agents

Phenytoin or Fosphenytoin

If the seizure persists after two adequate doses of benzodiazepine, administer phenytoin or fosphenytoin as the second-line anticonvulsant drug. Infusion of phenytoin at rapid rates can precipitate cardiac arrhythmias and hypotension. These unwanted side effects can be avoided by the use of fosphenytoin (a prodrug of phenytoin) which can be given faster than phenytoin. Fosphenytoin dosage is expressed as phenytoin equivalent (PE). The dose is 25-30 mg PE/kg IV at a rate up to 150 PE/min. Administer phenytoin 25-30 mg/kg by IV infusion ...