Chapter 76. Seizures and Status Epilepticus in Children

The causes and manifestations of seizure activity are numerous, ranging from benign to life threatening. Precipitants of seizures can include head injury, structural brain abnormalities, fever, CNS infection, hypoglycemia, electrolyte abnormalities, hypoxemia, toxin exposure, dysrhythmias, metabolic disorders, congenital infections, or neurocutaneous syndromes.

The clinical features of seizure activity depend on the area of the brain affected and can range from classic tonic-clonic movements to very subtle behavioral changes; they may be generalized (with loss of consciousness) or partial (with focal motor or behavioral features). Rhythmic repetitive movement, incontinence of bowel or bladder, postictal state after a seizure, and tongue biting are strong clues to a seizure.

Motor changes (tonic or clonic) may be focal or generalized, and seizures may present with atony (sudden loss of tone or “drop attack”) in some age groups. More subtle symptoms include staring spells (“absence”) or changes in mental status or behavior, which can be complex, such as automatisms (blinking, bicycling, or lip smacking in infants), vocalizations, or hallucinations.

Signs may include alteration in autonomic dysfunction, such as mydriasis; diaphoresis; tachypnea or apnea; tachycardia; hypertension and salivation; and postictal somnolence. Transient focal deficits may represent Todd's paralysis following a seizure.

The diagnosis of seizure disorder is based primarily on history and physical examination. Bedside glucose testing should be performed on all children who are seizing or postictal, but the clinical scenario should direct additional laboratory and imaging tests. Screening tests for electrolytes are not indicated in most cases of childhood seizures including simple febrile seizures or first time afebrile seizures, unless otherwise indicated by the specific history. The suggested ED evaluation of differing clinical scenarios presenting with seizure is listed in Table 76-1.

Status epilepticus, traditionally defined as seizure activity lasting for > 30 min, or multiple seizures without a return to normal mental status between seizures. Five minutes has been suggested as an operational definition because seizures lasting longer than 5 min usually do not resolve without treatment. Status epilepticus is a medical emergency, and is more responsive to medications when treated early and aggressively.

Seizures must be distinguished from other events that masquerade as seizures in children such as breath-holding, syncope, gastroesophageal reflux (Sandifer syndrome), chorea (acute rheumatic fever), myoclonic jerks, rigors, startle reflex, tics, pseudo-seizures and night terrors. Primary seizures should be distinguished from seizures secondary to treatable or life-threatening causes such as trauma, infection, hypoglycemia, metabolic abnormalities, or electrolyte abnormalities.

The management of the seizing child requires immediate supportive care, termination of the seizure with medication, and correction of reversible causes such as hypoglycemia or metabolic abnormalities.

1. Ensure a patent airway, apply oxygen to all seizing patients, and assist ventilation as indicated. If rapid-sequence intubation is required, continuous EEG monitoring should be arranged as neuromuscular blockade obscures the ability to clinically assess for ongoing seizures.

2. Treat hypoglycemia with 4 to 5 mL/kg 10% dextrose in infants or 2 mL/kg 25% dextrose in older children IV/IO.

3. Administer lorazepam, 0.1 milligram/kilogram or midazolam 0.1 to 0.2 milligram/kilogram IV/IO. If vascular access is not available, administer midazolam 0.2 milligram/kilogram IN (maximum dose 10 milligrams). Repeat benzodiazepine dose in 5 min if seizure persists and prepare to support breathing and blood pressure with repeated dosing.

4. Administer second-line anti-epileptic drugs if more than 2 doses of benzodiazepine are required. For infants, use phenobarbital 20 milligrams/kilogram IV/IO (maximum 800 milligrams) and for older children use fosphenytoin 20 PE/kilogram IV/IO over 20 min.

5. For refractory status epilepticus, administer third-line agents such as: valproic acid 20 milligrams/kilogram IV/IO, or levetiracetam 20 to 30 milligrams/kilogram IV/IO.

6. Fourth-line treatment strategies include continuous infusions in the ICU setting of propofol, midazolam, or pentobarbital, or induction of general inhaled anesthesia, such as: propofol 0.5 to 2.0 milligram/kilogram or 1.5 to 4.0 milligrams/kilogram/h IV/IO; or midazolam continuous infusion: 0.05 to 0.4 milligram/kilogram/h IV/IO.

7. Treat electrolyte abnormalities as follows: for hyponatremia < 120 mEq/L, 3% NaCl 4 to 6 mL/kg, for hypocalcemia, < 7 milligrams/dL of calcium and < 0.8 mmol/L of ionized calcium, 0.3 mL/kg of 10% calcium gluconate, over 10 min, and for hypomagnesemia < 1.5 mEq/L, 50 milligrams/kilogram of magnesium sulphate over 20 min.

Children who present to the ED following a brief seizure and who regain a normal mental status without focal neurologic deficits are candidates for discharge and outpatient follow-up. Patients presenting to the ED with ongoing seizures meet the definition for status epilepticus and these patients, even when termination is achieved in the ED should be admitted to the hospital for further observation. All infants with true seizures should be admitted to the hospital, as well. Patients with refractory seizures, those with seizures from acute traumatic brain injury, CNS infection, or serious metabolic or electrolyte abnormalities typically require treatment in the ICU setting.

Febrile Seizure

Seizures in the setting of fever are common in children and usually benign. Simple febrile seizures (SFS) occur between 6 months and 6 years of life, are brief (<15 min), and generalized. Patients with SFS require no specific ED evaluation or medication for their seizure, though evaluation for a treatable source of fever, and antipyretics may be indicated. Children experiencing simple febrile seizure have the same 1% risk of developing epilepsy as the general population. Complex febrile seizures (>15 min in duration, focal, or recurrent) carry a slightly increased risk for epilepsy, but also do not routinely require ED evaluation or treatment. Febrile status epilepticus is treated as above with the addition of neuroimaging, CSF analysis and culture, and potential antibiotics and acyclovir in the right setting.

First Seizure

The overall risk of recurrence after a single afebrile seizure is about 40%. Emergent neuroimaging is not necessary in the ED in the patient with a nonfocal neurologic exam, though outpatient MRI and EEG may be of benefit. Most neurologists do not recommend starting anti-convulsant medication after a first seizure.