Differential Diagnosis for Unexplained Fever
Single Most Likely Diagnosis
- Viral infection: This is often the most common cause of unexplained fever, as many viral infections can present with non-specific symptoms such as fever, fatigue, and malaise. Justification: High prevalence, non-specific presentation.
Other Likely Diagnoses
- Bacterial infection: Bacterial infections, such as pneumonia, urinary tract infections, or skin infections, can also cause unexplained fever. Justification: Common causes of fever, may not always present with typical symptoms.
- Inflammatory conditions: Conditions like rheumatoid arthritis, lupus, or inflammatory bowel disease can cause fever without a clear infectious source. Justification: Systemic inflammation can lead to fever.
- Medication side effect: Certain medications, such as antibiotics, antihistamines, or decongestants, can cause fever as a side effect. Justification: Common medications with known side effects.
Do Not Miss Diagnoses
- Septicemia: Bacterial sepsis can present with unexplained fever and is a life-threatening condition if not promptly treated. Justification: High mortality rate if missed.
- Meningitis: Infection of the meninges can cause fever, headache, and stiff neck, and is a medical emergency. Justification: High risk of neurological damage or death if missed.
- Endocarditis: Infection of the heart valves can cause unexplained fever, and is a serious condition if not treated promptly. Justification: High risk of cardiac complications or embolic events if missed.
- Tuberculosis: TB can cause chronic fever, weight loss, and night sweats, and is a significant public health concern. Justification: High risk of transmission and complications if missed.
Rare Diagnoses
- Lymphoma: Certain types of lymphoma, such as Hodgkin's disease, can cause unexplained fever, night sweats, and weight loss. Justification: Rare, but potentially life-threatening if missed.
- Factitious fever: Fabricated or induced fever, often for attention or financial gain. Justification: Rare, but important to consider in certain contexts.
- Autoinflammatory disorders: Conditions like familial Mediterranean fever or periodic fever syndrome can cause recurrent, unexplained fever. Justification: Rare, but important to consider in patients with recurrent fevers.