Differential Diagnosis for an 18-year-old Male with Persistent Fever
The patient presents with persistent fever, headache, fatigue, and malaise, but lacks upper respiratory or GI symptoms, rash, and lymphadenopathy. Routine labs and chest x-ray are unremarkable. Here's a categorized differential diagnosis:
- Single most likely diagnosis
- Infectious Mononucleosis (Mono): Although the patient denies upper respiratory symptoms, mono can present with fever, headache, and fatigue. The lack of lymphadenopathy does not rule out this diagnosis, as it may not always be present.
- Other Likely diagnoses
- Viral Syndrome: A non-specific viral illness could explain the patient's symptoms, especially given the lack of specific findings on routine labs and chest x-ray.
- Influenza: Although the patient denies upper respiratory symptoms, influenza can present with fever, headache, and fatigue, especially in the early stages.
- Brucellosis: This zoonotic infection can cause fever, headache, and fatigue, and may not have specific findings on routine labs or chest x-ray.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed)
- Meningitis: Although the patient denies specific symptoms like stiff neck or photophobia, meningitis can present with non-specific symptoms like fever and headache, and is a medical emergency.
- Endocarditis: Infective endocarditis can cause persistent fever, fatigue, and malaise, and may not have specific findings on routine labs or chest x-ray.
- Tuberculosis (TB): TB can present with non-specific symptoms like fever, fatigue, and malaise, and may not have specific findings on routine labs or chest x-ray.
- Rare diagnoses
- Lymphoma: Although rare, lymphoma can present with non-specific symptoms like fever, fatigue, and malaise, and may not have specific findings on routine labs or chest x-ray.
- Histoplasmosis: This fungal infection can cause fever, headache, and fatigue, and may not have specific findings on routine labs or chest x-ray.
- Q Fever: This zoonotic infection can cause fever, headache, and fatigue, and may not have specific findings on routine labs or chest x-ray.