Clinical meaning
Febrile seizures arise from the convergence of age-dependent neuronal hyperexcitability and systemic inflammatory response. The immature brain exhibits enhanced excitatory amino acid (glutamate, aspartate) neurotransmission, reduced GABAergic inhibition, and incomplete axonal myelination, creating a low seizure threshold. Pyrogens (IL-1β, IL-6, TNF-α, PGE2) act on hypothalamic thermoregulatory centers to reset the temperature set-point while simultaneously enhancing neuronal excitability through direct effects on ion channel kinetics—accelerating sodium channel recovery and reducing potassium conductance. Genetic susceptibility loci (FEB1-FEB8) influence channelopathy variants, particularly SCN1A and GABRG2 mutations, which overlap with genetic epilepsy syndromes. The clinician must conduct differential diagnosis, order and interpret diagnostic workup, prescribe treatment, determine need for neuroimaging or EEG, and manage long-term seizure recurrence planning.
Diagnosis & workup
Diagnostics & workup: - Order CBC with differential, CMP, blood glucose, blood culture if toxic-appearing - Order urinalysis and urine culture (UTI is common occult source in febrile children <2 years) - Determine need for lumbar puncture: required if <6 months, strongly consider if 6-12 months or unimmunized against H. influenzae type b and S. pneumoniae - Interpret CSF results: cell count, protein, glucose, Gram stain, culture, and viral PCR panel - Order EEG only if complex features present or neurological exam is abnormal post-ictally - Order neuroimaging (MRI preferred over CT) only if focal neurological deficit, prolonged post-ictal state, or concern for structural lesion - Evaluate iron studies (ferritin, serum iron, TIBC) if recurrent febrile seizures