Differential Diagnosis for Fever in a Patient with Normal CD4 Count and Negative Imaging Studies
Single Most Likely Diagnosis
- Viral syndrome: Given the patient's presentation with fever and headache, and the lack of specific findings on imaging studies, a viral syndrome is a plausible explanation. The patient's recent history of being in a county jail, where infectious diseases can spread more easily, supports this diagnosis.
Other Likely Diagnoses
- Tuberculosis (TB): Although the Quantiferon test is negative, it is not 100% sensitive, especially in immunocompromised patients or those with certain forms of TB. The patient's birth in Vietnam, a country with a high prevalence of TB, and the fact that TB can be asymptomatic for a long time, make this a consideration.
- Influenza or other respiratory viruses: These are common causes of fever and headache, especially in someone who has been in a crowded environment like a jail.
- Medication-induced fever: If the patient is taking any medications, these could be a cause of fever, although there is no specific information provided about current medications.
Do Not Miss Diagnoses
- Endocarditis: Although less likely given the lack of specific cardiac findings, endocarditis can present with fever and non-specific symptoms. It is a diagnosis that could be deadly if missed.
- Neurosyphilis: Given the patient's HIV status and potential for exposure to sexually transmitted infections, neurosyphilis is a possibility, especially with headache as a symptom.
- Lymphoma: Although rare, lymphoma can present with fever and non-specific symptoms. Given the patient's HIV status, there is an increased risk of lymphoma.
Rare Diagnoses
- Meliodosis: Given the patient's history of living in Hawaii and being born in Vietnam, both areas where melioidosis is more common, this rare bacterial infection could be considered, especially if the patient had exposure to contaminated water.
- Leptospirosis: Despite the patient's denial of exposure to animals, leptospirosis is a rare but possible diagnosis, especially if the patient had contact with contaminated water during their time in Hawaii or Vietnam.
- Brucellosis: This zoonotic infection is rare but could be considered if the patient had unknowingly consumed unpasteurized dairy products or had contact with infected animals, despite their reported lack of exposure.