Approach to a first unprovoked seizure (pediatrics): Clinical sciences

Seizures are paroxysmal events caused by abnormal neuronal activity in the brain, and they are considered unprovoked if no acute precipitant can be identified. Seizures present with a wide variety of manifestations, including focal or generalized motor activity and altered awareness. Unprovoked seizures can be categorized as either isolated unprovoked seizures or as epilepsy, which can be further classified as distinct syndromes with onset during infancy, childhood, or adolescence.

If a pediatric patient presents with a chief concern suggesting a first unprovoked seizure, start with an ABCDE assessment. If the patient is unstable, first stabilize the airway, breathing, and circulation, and you may even need to intubate the patient. Next, obtain IV access, and consider starting IV fluids. Begin continuous vital sign monitoring, including blood pressure, heart rate, and oxygen saturation. Provide supplemental oxygen if needed, and administer an anti-seizure medication if the seizure lasts longer than 5 minutes.

Now here’s a clinical pearl! A convulsive seizure lasting longer than 5 minutes is considered status epilepticus. This neurologic emergency requires prompt administration of benzodiazepines, followed by anti-seizure medications like fosphenytoin or phenobarbital. Once stabilized, a patient with status epilepticus requires further diagnostic evaluation!

Okay, let’s go back to the ABCDE and look at stable patients. First, obtain a focused history and physical exam, and consider ordering labs, such as a CMP and blood or urine toxicology screening. Caregivers typically report an episode of focal or generalized motor activity that could be described as tonic, which involves increased tone or rigidity; clonic, which consists of fast, rhythmic contractions; myoclonic, which is a shock-like muscle contraction; atonic, which is characterized by muscle flaccidity; or tonic-clonic, which starts with stiffening of the whole body followed by rhythmic jerks.

Some patients also experience impaired consciousness or unresponsiveness during the seizure. Verbal patients might describe an aura, which is a sensory experience like flashing lights, that precedes the seizure. History will reveal no previous seizures and no recent head trauma.

Physical exam findings will include no signs suggesting a central nervous system infection, such as meningeal signs or neck stiffness, and no signs of increased intracranial pressure, such as papilledema. If your patient presents soon after the seizure has resolved, they might exhibit signs indicating a postictal state, such as drowsiness, decreased awareness, or confusion. Some might demonstrate Todd paresis or paralysis, which is temporary weakness or paralysis of one side of the body following a seizure. If labs were ordered, results typically reveal normal electrolytes and glucose, as well as a negative toxicology screen. With these findings, consider an unprovoked seizure.

Here’s a high-yield fact! Some nonepileptic events are commonly mistaken for seizure activity. For example, breath-holding spells during toddlerhood are associated with stiffening and pallor or cyanosis. Other behaviors and movements that mimic seizures include tics, stereotypies, tantrums, and panic attacks, as well as sleep-related disorders such as parasomnias and periodic leg movements. You should also consider psychogenic non-epileptic seizures, characterized by sudden, involuntary movements or alterations in consciousness that mimic epileptic seizures, yet they are not caused by abnormal electrical discharges in the brain. Instead, they’re thought to stem from psychological factors, such as unresolved emotional trauma or stress. Finally, neonatal conditions that can be mistaken for seizures include benign neonatal sleep myoclonus and jitteriness resulting from an immature nervous system.

And another clinical pearl! Febrile seizures commonly occur during acute illness in healthy children between 6 months and 5 years of age. By definition, febrile seizures are provoked by fever, and affected children have no previous history of unprovoked seizures. Remember that these children don’t require EEG, neuroimaging, or other diagnostic workup, and treatment involves supportive care and antipyretics, not antiepileptic medications! Of note, just like sleep deprivation and hyperventilation, fever can trigger seizures in children with epilepsy too!

So now you’re considering an unprovoked seizure. Your next step is to obtain an electroencephalogram, or EEG; with hyperventilation, sleep deprivation, or photic stimulation if needed. Additionally, consider ordering an MRI of the brain if your patient experienced a focal seizure, or if they have postictal neurologic deficits or prolonged postictal mental status changes.

After you have reviewed the EEG findings, you should assess your patient for epilepsy diagnostic criteria. A diagnosis of epilepsy requires at least two unprovoked seizures more than 24 hours apart, or EEG findings and a clinical history suggesting that seizures are likely to recur. If criteria are not met, then diagnose an isolated unprovoked seizure.

However, if criteria are met, you can diagnose epilepsy. Next, assess the age of onset, to evaluate your patient for the presence of an epilepsy syndrome. Pediatric epilepsy syndromes are characterized by distinct seizure types and triggers, characteristic EEG findings, and typical age of onset.

First, let’s discuss unprovoked seizures that begin during infancy. In this case, you’ll need to assess your patient’s development.