American Board of Internal Medicine (ABIM) Certification Practice Exam

How many weeks after the infectious trigger does reactive arthritis typically occur?

1. 1 to 2 weeks

2. 2 to 4 weeks

3. 3 to 6 weeks

4. 6 to 8 weeks

The correct answer is: 3 to 6 weeks

Reactive arthritis is a type of inflammatory arthritis that arises in response to an infection in another part of the body, often in the genitourinary or gastrointestinal systems. The timing of the onset of reactive arthritis is important for diagnosis and management. Typically, reactive arthritis manifests within a time frame of 3 to 6 weeks following the initial infection or infectious trigger. The timeframe of 3 to 6 weeks is consistent with the body's immune response to the infectious agent. After the primary infection, it takes the immune system some time to mount a response, including the development of antibodies and other inflammatory mediators that can lead to joint involvement. In contrast, the shorter timeframes of 1 to 2 weeks and 2 to 4 weeks are often observed in other types of post-infectious responses, including those seen in acute bacterial infections where joint symptoms may arise more quickly. The longer timeframe of 6 to 8 weeks is beyond the typical duration for reactive arthritis to present itself, as an immune-mediated response generally initiates within the previously mentioned window. Understanding this timeline can aid in the diagnostic process for individuals presenting with joint pain following an infection, helping healthcare providers differentiate reactive arthritis from other arthritic conditions.