Febrile seizure (pediatrics): Clinical sciences

Febrile seizures occur in children 6 months to 5 years of age, with a temperature of at least 38 degrees Celsius, and without concurrent central nervous system infection, metabolic disturbance, or history of prior afebrile seizures. Based on the child’s manifestations, febrile seizures can be classified as simple or complex.

Now, if a pediatric patient presents with a chief concern suggesting febrile seizure, you should first perform an ABCDE assessment to determine whether they are unstable or stable. If the patient is unstable, first stabilize the airway, breathing, and circulation, obtain IV access, and consider starting IV fluids. Next, put your patient on continuous vital sign monitoring, including heart rate, blood pressure, and oxygen saturation. Finally, if needed, don’t forget to provide supplemental oxygen to maintain saturation, and consider administering an anti-seizure medication.

Now here’s a clinical pearl to keep in mind! If your patient experiences a seizure in front of you, and the seizure activity persists for 5 minutes or more, place them on their side, on a flat surface, and administer a short-acting benzodiazepine such as IV lorazepam or IM midazolam as first choices, or rectal diazepam as second choice.

If the seizure doesn’t resolve after two doses of a benzodiazepine or after 20 minutes of seizure activity, administer a different anti-seizure medication, such as IV phenobarbital if your patient is an infant, or IV fosphenytoin if they are an older child.

A febrile seizure lasting longer than 30 minutes is considered febrile status epilepticus, which is a neurologic emergency requiring the prompt administration of additional anti-seizure medication and further diagnostic evaluation.

Now, let's go back and take a look at stable patients. In this case, your first step is to obtain a focused history and physical exam. History typically reveals a high or rapidly rising fever before the onset of a seizure. Ask the caregivers to describe the seizure activity, which could be generalized or limited to one extremity. Caregivers might also report a recent infection associated with high fever, such as roseola, or recent administration of immunizations, such as diphtheria-tetanus-pertussis or measles-mumps-rubella. In addition, there might be a family history of febrile seizures. Finally, the physical examination will often reveal a temperature of at least 38 degrees Celsius, possibly with tachycardia. Moreover, if the seizure recently resolved, your patient may display postictal drowsiness or confusion.

With these findings, you should suspect a febrile seizure, so your next step is to assess your patient’s age and look for signs of central nervous system infection.

If your patient is under 6 months of age, or if the physical exam reveals signs suggesting central nervous system infection, such as irritability or bulging fontanelles, then you should consider alternative diagnoses, like meningitis.

Now, here’s a clinical pearl to keep in mind! Children with febrile seizures have an increased likelihood of a central nervous system infection like bacterial meningitis if they are between 6 and 12 months old, and are not fully immunized against Haemophilus influenzae type B and Streptococcus pneumoniae; or if they have had recent antibiotic use, since antibiotics can mask the signs and symptoms of meningitis. These children should undergo further evaluation for central nervous system infection after a first febrile seizure.

On the other hand, if the child is between 6 months and 5 years of age, and the exam reveals no signs of a CNS infection, then you can diagnose a febrile seizure. Once you diagnose it, your next step is to assess the seizure characteristics and the neurologic exam findings.