Chapter 19. Seizures

Status Epilepticus

Essentials of Diagnosis

• A prolonged seizure lasting 5–15 minutes
• Continuous or multiple seizures without intervening periods of consciousness

Clinical Findings

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).

Protect the Airway

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).

Rule-Out Hypoglycemia

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

First-Line Agent

Benzodiazepines

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.

Second-Line Agent

Phenytoin or Fosphenytoin

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 ...