Differential Diagnosis for 16 yo Female with Fever, Headache, and Confusion
- Single most likely diagnosis:
- Viral meningitis or encephalitis: The patient's symptoms of fever, headache, and confusion are consistent with a viral infection affecting the meninges or brain tissue. The absence of nuchal rigidity does not rule out this diagnosis, as it can be absent in early stages or in certain types of viral infections.
- Other Likely diagnoses:
- Bacterial meningitis: Although the patient does not exhibit nuchal rigidity, bacterial meningitis is a serious condition that can present with fever, headache, and confusion. It is essential to consider this diagnosis due to its high morbidity and mortality if left untreated.
- Influenza or other viral infections with CNS involvement: Influenza and other viral infections can cause CNS symptoms, including fever, headache, and confusion, especially in severe cases.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed):
- Subarachnoid hemorrhage: Although less likely, a subarachnoid hemorrhage can present with sudden onset of headache and confusion. It is crucial to consider this diagnosis due to its high mortality rate if left untreated.
- Brain abscess or empyema: These conditions can cause fever, headache, and confusion, and are medical emergencies that require prompt treatment.
- Rocky Mountain spotted fever or other tick-borne illnesses: These illnesses can present with fever, headache, and confusion, and can be deadly if not treated promptly.
- Rare diagnoses:
- Autoimmune encephalitis: This is a rare condition that can cause fever, headache, and confusion, and is often associated with autoimmune disorders.
- CNS vasculitis: This is a rare condition that can cause fever, headache, and confusion, and is often associated with systemic vasculitis.
- Prion diseases (e.g., Creutzfeldt-Jakob disease): These are rare, degenerative disorders that can cause rapidly progressive dementia, confusion, and other neurological symptoms.