Differential Diagnosis for Pediatric Causes of Fever with Encephalopathy
Single Most Likely Diagnosis
- Viral Encephalitis: This is often the most common cause of fever with encephalopathy in pediatric patients, with herpes simplex virus (HSV) being a leading culprit. The presentation can include fever, altered mental status, seizures, and focal neurologic deficits.
Other Likely Diagnoses
- Bacterial Meningitis: Caused by pathogens like Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae type b, bacterial meningitis presents with fever, headache, stiff neck, and altered mental status.
- Severe Influenza: Influenza can cause encephalopathy, especially in pediatric patients, and is often associated with fever, respiratory symptoms, and sometimes seizures or focal neurologic signs.
- Autoimmune Encephalitis: Conditions like anti-NMDA receptor encephalitis can present with fever, psychosis, seizures, and decreased level of consciousness, although they are less common than infectious causes.
Do Not Miss Diagnoses
- Brain Abscess: Although less common, brain abscesses can present with fever, headache, and focal neurologic signs, and require urgent neurosurgical intervention.
- Subarachnoid Hemorrhage: While rare in children, subarachnoid hemorrhage can cause sudden onset of severe headache, fever (due to blood in the CSF), and altered mental status, necessitating immediate medical attention.
- Toxins/Poisoning: Certain toxins or poisonings (e.g., salicylates, carbon monoxide) can cause fever and encephalopathy and are critical to identify due to the potential for specific antidotes or interventions.
- Central Nervous System (CNS) Vasculitis: Conditions like primary CNS vasculitis can present with fever, headache, and encephalopathy, and require prompt recognition and treatment to prevent long-term sequelae.
Rare Diagnoses
- Prion Diseases: Extremely rare in children, prion diseases like Creutzfeldt-Jakob disease can cause progressive encephalopathy, but are typically not associated with fever.
- Mitochondrial Disorders: Certain mitochondrial disorders can present with episodes of encephalopathy and fever, often triggered by metabolic stressors.
- Acute Disseminated Encephalomyelitis (ADEM): A rare, immune-mediated condition that can occur after viral infections or vaccinations, ADEM presents with fever, encephalopathy, and multifocal neurologic signs.
- Rasmussen's Encephalitis: A rare, chronic inflammatory condition characterized by seizures, hemiparesis, and encephalopathy, often with a slow progression and associated with fever in some cases.