Seizures in Infants and Children

1. THE 2-MINUTE PHYSIOLOGY (Rapid Pathophysiology)

• The Excitatory Mismatch: Seizures are paroxysmal events characterized by temporary involuntary changes in motor activity, behavior, or autonomic function, caused by excessive synchronous electrical neuronal discharges of a group of cortical neurons. Infants and children under 5 years are highly susceptible because their immature nervous systems have a predominance of excitatory neuronal activity, underdeveloped inhibitory systems, and a paucity of synaptic connections.
• Status Epilepticus (SE) Cascade: Status epilepticus is defined as $\ge$ 5 minutes of continuous clinical or electrographic seizure activity, OR recurrent seizures without a return to baseline mental status. Prolonged excessive neuronal firing rapidly depletes energy stores and induces systemic stress, directly driving life-threatening complications including severe acidosis, hypoxia, neurogenic pulmonary edema, hyperthermia, rhabdomyolysis, and permanent neurological damage.

2. THE BEDSIDE ACTION PLAN (Rapid ER Management)

• Immediate Stabilization & ABCs: Prioritize airway protection. Apply a facemask with 100% oxygen, and initiate continuous pulse oximetry and ECG monitoring. Intubation with respiratory assistance must be considered if airway reflexes fail, but avoid long-acting neuromuscular blockade (like vecuronium) which masks ongoing clinical seizures.
• The Glucose Check: Obtain a STAT finger stick blood glucose for every seizing patient. Hypoglycemia is the most common metabolic cause of seizures. Dose: If < 60 mg/dL, administer 5 mL/kg of D10W IV.
• First-Line Abortive Therapy (Benzodiazepines): Early, aggressive administration decreases mortality.
• If IV access is established: Lorazepam IV.
• If IV access is delayed: Do not wait. Administer Midazolam IM (intramuscular midazolam is superior to delayed IV lorazepam) or via intranasal (IN) / buccal routes.
• Second-Line Antiepileptics: If seizures continue after benzodiazepines, administer Fosphenytoin or Levetiracetam.
• The Neonatal Pathway: For neonates, Phenobarbital is the first-line antiepileptic regardless of etiology (e.g., hemorrhage, ischemia). For refractory neonatal status epilepticus, you must administer Pyridoxine (100 mg IV) for pyridoxine-dependent epilepsy and Leucovorin (2.5 mg IV) for folinic acid deficiency.

3. THE DIAGNOSTIC GRID (Differential Diagnosis & Workup)

• Top "Can't-Miss" Differential Diagnoses:
• CNS Infection: Meningitis, encephalitis, or sepsis.
• Intracranial Trauma/Hemorrhage: Particularly abusive head trauma in infants.
• Metabolic Derangements: Hypoglycemia, hyponatremia.
• Toxicological Exposure: Ingestion of epileptogenic agents or withdrawal.
• Syncope/Dysrhythmia Mimic: Including prolonged QT syndrome causing cerebral hypoperfusion misidentified as a seizure.
• Prioritized Diagnostic Workup:
• Tier 1: Bedside blood glucose.
• Tier 2 (Directed Labs): U&E, calcium, magnesium, phosphate, LFTs, CBC, blood gas, and a toxicology screen if appropriate. Check anticonvulsant drug levels in patients with known epilepsy, as subtherapeutic levels are found in ~30% of these cases.
• Tier 3 (Lumbar Puncture): Perform an LP if the clinical exam is suggestive of meningitis, or strongly consider it in patients 6-12 months old who are unvaccinated against Hib/Pneumococcus, are currently on antibiotics, or who present with an unprovoked seizure and fail to return to baseline.

4. THE VISUAL BOARD (ECG / POCUS / Imaging)

• Non-Contrast CT Head: Required emergently to evaluate for intracranial bleeding, masses, or abusive head trauma. It is specifically mandated for patients with persistent focal neurologic deficits, a history of trauma, or a prolonged postictal period without return to baseline.
• 12-Lead ECG: Must be obtained to rule out syncope mimics such as Long QT Syndrome, Brugada syndrome, or toxicological widened QRS mimicking a primary seizure event.

5. THE SCORING MATRIX (Risk Stratification & Guidelines)

• Febrile Seizure Criteria: Occurs in children aged 6 months to 5 years (peak at 18 months) with a temperature $\ge$ 38.0°C.
• Simple Febrile Seizure (SFS):
• Criteria: Generalized tonic-clonic, duration < 15 minutes, neurologically normal child, no prior afebrile seizures, and no recurrence within 24 hours.
• Disposition: Routine laboratory work, LP, neuroimaging, and EEGs are not indicated. Discharge home safely after finding the fever source.
• Complex Febrile Seizure (CFS):
• Criteria: Duration > 15 minutes, focal onset, recurrence within 24 hours, or the presence of a postictal focal neurologic abnormality (e.g., Todd paralysis).
• Disposition: Requires targeted diagnostic testing, neurology consultation, and potential admission.

6. THE DANGER ZONE (Pitfalls & Critical Actions)

• The IV Access Trap: Pitfall: Delaying anticonvulsant therapy while searching for pediatric IV access. Critical Action: Early IM midazolam or IN/buccal benzodiazepines must be administered immediately if IV access is difficult; seizures become progressively more refractory the longer they last.
• The LP Delay: Pitfall: Withholding lifesaving antibiotics/antivirals while awaiting an LP or CT scan in a child with SE and suspected meningitis. Critical Action: Empiric antimicrobial therapy must not be delayed by neuroimaging or LP attempts.
• The Antipyretic Fallacy: Pitfall: Recommending scheduled antipyretics to parents to prevent future simple febrile seizures. Critical Action: Explicitly counsel parents that aggressive fever management does not impact febrile seizure recurrence rates. Antipyretics should only be given for patient comfort.

7. MCQ MASTERCLASS (Written Exam Tips)

• Buzzwords: "Postictal temporary focal neurologic abnormality" or "weakness on one side." Diagnosis: Todd Paralysis, making it a Complex Febrile Seizure regardless of duration.
• Most Common Fact: The most common metabolic cause of pediatric seizure activity is Hypoglycemia.
• Common Distractor: A neonate is in refractory status epilepticus despite adequate doses of phenobarbital and midazolam. An option will suggest "Intubate and paralyze with vecuronium."
• Differentiate: Long-acting paralytics mask the clinical signs of seizures without treating the brain. The correct next step for refractory neonatal status epilepticus is administering IV Pyridoxine (100 mg) to treat potential pyridoxine-dependent epilepsy.

8. THE BOARDROOM SCRIPT (OSCE & Oral Board Tips)

• The Opening Salvo: "This pediatric patient is presenting in active status epilepticus. My immediate priorities are airway, breathing, and circulation. I will place the patient on a cardiac monitor, provide 100% oxygen via facemask, and obtain a STAT bedside blood glucose. I need my team to prepare IM Midazolam immediately in case IV access is delayed."
• Articulating the Resuscitation: "The patient's glucose is 45 mg/dL. I will administer 5 mL/kg of D10W IV immediately. Because the seizure has continued past 5 minutes, I am giving weight-based IV Lorazepam. If the seizure does not terminate, I will escalate to second-line agents such as Fosphenytoin or Levetiracetam, and prepare equipment for airway management, deliberately avoiding long-acting paralytics."
• Counseling the Simple Febrile Seizure (Parent Communication): "I know witnessing your child seize is incredibly frightening. Your child had what we call a simple febrile seizure. These are relatively common, benign, and do not cause brain damage. The risk of developing epilepsy is only slightly higher than the general population. We can give Tylenol to make them comfortable, but I want to be clear that fever-reducing medications will not prevent another seizure from happening."