Status Epilepticus: Evaluation and Management

ABSTRACT: Status epilepticus (SE) is associated with high morbidity and mortality in children. Fever is a common cause of SE and may precipitate seizures in children who have underlying epilepsy risk factors or may signal intracranial infection. Metabolic abnormalities, such as hypoglycemia, can also cause SE. Early termination of SE is the goal of therapy. Nonintravenous benzodiazepines can be initiated at home or en route to the hospital. Use of anticonvulsants depends on the progression of the seizure. Children with SE need to be hospitalized for a comprehensive evaluation of the seizure etiology done in consultation with a pediatric neurologist. When counseling parents, address the social and academic repercussions of epilepsy and emphasize first aid measures and use of medications, such as rectal benzodiazepines.

Seizures occur in 10% of children.1 Status epilepticus (SE)-perhaps the most severe type of seizure-is one of the most common neurological emergencies in children and is associated with high morbidity and mortality. The estimated incidence of convulsive SE is between 17 and 23 episodes per 100,000 children per year.² SE is most common in the first year of life, and febrile seizure is the most common cause.³ SE occurs as the first seizure in 12% of children with epilepsy.³

Adverse outcomes, such as postseizure neurological abnormalities and aspiration pneumonia, are directly related to the length of the seizure episode. Pediatricians who are comfortable with managing seizures, especially SE, can greatly reduce the adverse outcomes associated with prolonged seizures. In this article, I review the acute management of convulsive SE, which is more common than nonconvulsive SE and likely to present as an emergency to practitioners in a clinic setting or in the emergency department (ED). I also provide a clinically useful algorithm that can be initiated in the office and continued in the ED. Finally, I briefly discuss postseizure management.

DEFINITIONS

Seizure. A seizure is defined as a transient occurrence of signs and symptoms caused by abnormal excessive or synchronous neuronal activity in the brain. Seizures are initially classified as either generalized or partial: 

• Generalized seizures involve the entire cortex, and consciousness is usually lost.

• Partial seizures begin in one portion of the brain and have symptoms related to that region’s function. These seizures may remain restricted to one location without affecting alertness (simple partial seizure); they may spread to adjacent regions and affect consciousness (complex partial seizures); or they may spread across the entire cortex (secondary generalization). 

Seizures are often isolated events that terminate spontaneously within several minutes. However, they can present as recurrent episodes in close proximity, with recovery between episodes (repetitive seizures); or they may be continuous, or frequent, without recovery between episodes (SE).

Status epilepticus. SE can be divided into 2 types:

• Nonconvulsive SE consists of continuous abnormal electroencephalographic (EEG) activity without convulsive activity in the presence of altered sensorium.

• Convulsive SE is typically tonicclonic in nature and can be generalized or partial with secondary generalization. 

Convulsive SE is defined as either 2 or more convulsions without complete recovery of consciousness or a single prolonged seizure episode that lasts for at least 30 minutes.^2,4 Because of the high morbidity and mortality associated with SE and the recognition that antiseizure medications are less effective in terminating prolonged seizures, some experts have recommended shortening the minimum seizure duration in the SE criteria from 30 minutes to 5 minutes.⁵

Epilepsy. When 2 or more unprovoked seizures occur more than 24 hours apart, epilepsy is diagnosed. Epilepsy is initially divided into symptomatic and idiopathic types and then further classified as generalized and localized on the basis of the clinical presentation along with EEG findings.

CAUSES

Fever is a common cause of seizures and SE in children. Some children will present in SE with their first febrile seizure. In some cases, the fever may be secondary to the convulsive movements. Fever may precipitate seizures in children who have underlying epilepsy risk factors, such as cerebral palsy. Intracranial infections, such as meningitis and encephalitis, can also present with fever and seizures. Children may also have seizures because of the presence of metabolic abnormalities, such as hypoglycemia, hyponatremia, hypocalcemia, and hypomagnesemia. For a list of the more common causes of SE in children, see Table 1.

MANAGEMENT OF CONVULSIVE SE

Early termination of seizures substantially reduces morbidity and mortality and is the goal of therapy. The Algorithm provides a guide to the most recent approach to the treatment of a child in convulsive SE.

Most important is to turn the patient on his or her side-assuming that there has been no neck trauma. If in the clinic or ED, perform a rapid blood glucose test to determine whether hypoglycemia is the cause of the seizure.

Prehospital treatment. Treatment that begins at home or during the prehospital transport has been shown to be safe and effective. Therapy with a benzodiazepine (intramuscular midazolam, buccal midazolam, intranasal midazolam, or rectal diazepam) can be initiated in the absence of intravenous access. Rectal diazepam is often prescribed for children with febrile seizures and prolonged or repetitive seizures as a part of their home care.

In-hospital treatment. Use of anticonvulsants depends on the progression of the seizures.⁶ Although most seizure episodes, even in patients with poorly controlled epilepsy, tend to terminate spontaneously, it is impossible to predict which seizure episodes will progress to SE. Thus, health care providers should anticipate and be ready to initiate further medical treatment.

The principles that guide medication choices for convulsive SE include:

• Ability to be administered rapidly.

• Fast penetration of the brain.

• Minimal systemic adverse effects.

• Use by nonintravenous route, if possible.

A multidisciplinary team including, but not limited to, pediatric emergency and critical care specialists is necessary for general supportive care. These providers attend to the airway, breathing, and circulation; treat underlying causes; and prevent and treat systemic complications.

In addition to a rapid blood glucose test to rule out hypoglycemia, it is important to test for hyponatremia, hypocalcemia, and hypomagnesemia at the initial evaluation and to treat these conditions appropriately (Table 2). However, empiric treatment should not be delayed while waiting for test results.

Postseizure evaluation and management.

Children with SE need to be hospitalized for a comprehensive evaluation of the seizure etiology, which must be done in consultation with a pediatric neurologist. Evaluation should include a detailed history, developmental history, family history, and exposure to any medications or recent travel. In addition, based on the etiology, cerebrospinal fluid analysis, MRI, or CT scanning, along with electroencephalography, is often indicated. Subsequent management, including type of antiepileptic medication, will depend on the cause of the seizure and type of epilepsy indicated by the EEG findings.

Parents require support and accurate information about the prognosis of the seizure-causing condition. It is also important to counsel parents about the adverse effects of medications and the social and academic repercussions of epilepsy. In most instances, restriction of physical activity is unnecessary; however, a responsible adult needs to be present when the child is bathing or swimming.

First aid measures and use of medications, such as rectal benzodiazepines, along with fever management should be emphasized. Fortunately, most children who are adherent to medications tend to have normal IQs and can be expected to lead normal lives.

Dowload Algorithm

References:

REFERENCES:1. Johnston MV. Seizures in childhood. In: KliegmanRM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia:Saunders; 2007:2457-2478.
2. Chin RF, Neville BG, Peckham C, et al;NLSTEPSS Collaborative Group. Incidence, cause,and short-term outcome of convulsive status epilepticusin childhood: prospective population-basedstudy. Lancet. 2006;368:222-229.
3. Novorol CL, Chin RF, Scott RC. Outcome of convulsivestatus epilepticus: a review. Arch Dis Child.2007;92:948-951.
4. Neville BG, Chin RF, Scott RC. Childhood convulsivestatus epilepticus: epidemiology, managementand outcome. Acta Neurol Scand Suppl. 2007;186:21-24.
5. Pellock JM. Overview: definitions and classificationsof seizure emergencies. J Child Neurol. 2007;22(5 suppl):9S-13S.
6. Abend NS, Huh JW, Helfaer MA, Dlugos DJ.Anticonvulsant medications in the pediatric emergencyroom and intensive care unit. Pediatr EmergCare. 2008;24:705-718.
7. Shorvon SD, Pellock JM, DeLorenzo RJ. Acutephysiologic changes, morbidity, and mortality ofstatus epilepticus. In: Engel J Jr, Pedley T, eds. Epilepsy: A Comprehensive Textbook. 2nd ed. Philadelphia:Lippincott Williams & Wilkins; 2008:747.

FOR MORE INFORMATION:
• Appleton R, Choonara I, Martland T, et al. The treatment of convulsive status epilepticus in children. The Status Epilepticus Working Party, Members of the Status Epilepticus Working Party. Arch Dis Child. 2000;83:415-419.

• Guidelines for status epilepticus treatment. Epilepsy.com/professionals. 2009. http:// professionals.epilepsy.com/page/table_epilepticus_ guidelines.html. Accessed November 5, 2009.