Differential Diagnosis for Fever with Arthritis
Single Most Likely Diagnosis
- Viral Arthritis: This is often the most common cause of fever and arthritis, with viruses such as parvovirus B19, hepatitis B, and rubella being frequent culprits. The justification for this being the single most likely diagnosis is the high prevalence of viral infections in the general population and their known association with both fever and arthritis.
Other Likely Diagnoses
- Bacterial Arthritis (Septic Arthritis): Caused by bacteria such as Staphylococcus aureus, Streptococcus pneumoniae, and Neisseria gonorrhoeae. This condition is a medical emergency and requires prompt treatment. It's likely because bacterial infections are common and can easily lead to septic arthritis, especially in certain risk groups.
- Lyme Disease: Caused by Borrelia burgdorferi, transmitted by ticks. It's a likely diagnosis in endemic areas, especially during certain times of the year, and can cause fever, arthritis, and other systemic symptoms.
- Reactive Arthritis: This form of arthritis occurs as a reaction to an infection elsewhere in the body, often in the gastrointestinal tract or the urethra. It's likely because it's a well-documented sequela of certain bacterial infections.
Do Not Miss Diagnoses
- Gonococcal Arthritis: Although less common, gonococcal arthritis is a critical diagnosis not to miss due to its potential for severe consequences if left untreated, including destruction of the joint and dissemination of the infection.
- Tuberculous Arthritis: Caused by Mycobacterium tuberculosis, this condition can have severe outcomes if not promptly diagnosed and treated. It's especially important in areas with high TB prevalence or in immunocompromised patients.
- Lyme Meningitis or Neuroborreliosis: In the context of Lyme disease, it's crucial not to miss central nervous system involvement, which can present with fever and arthritis among other symptoms.
Rare Diagnoses
- Rheumatic Fever: Although rare in developed countries, rheumatic fever can occur after a group A streptococcal infection and presents with fever, arthritis, and other symptoms. It's a rare but important diagnosis due to its potential for cardiac complications.
- Whipple's Disease: A rare, systemic bacterial infection caused by Tropheryma whipplei, which can present with fever, arthritis, and gastrointestinal symptoms among others. It's rare but critical to diagnose due to its severity and response to treatment.
- Brucellosis: A zoonotic infection that can cause fever, arthritis, and other systemic symptoms. It's rare in many parts of the world but can be seen in individuals who work with animals or consume unpasteurized dairy products, especially in endemic areas.