The Correct Statement is (b): Macrophage Activation Syndrome in Juvenile Idiopathic Arthritis
Statement (b) is correct: Persistent fever accompanied by pancytopenia, elevated ferritin levels, and a flare-up of disease symptoms in the context of juvenile idiopathic arthritis raises suspicion of macrophage activation syndrome (MAS). This represents a life-threatening complication that requires immediate recognition and treatment 1.
Why Statement (b) is Correct
According to the 2024 EULAR/PReS recommendations for Still's disease (which encompasses systemic juvenile idiopathic arthritis), MAS should be considered in patients with persistent fever, inappropriately low cell counts (pancytopenia), and elevated or rising serum ferritin 1. The guidelines explicitly state that:
- MAS should be detected promptly and treated rapidly (100% agreement, level of agreement 10/10)
- Severe/life-threatening complications including MAS may develop at any point during the disease course
- Additional indicators include splenomegaly, abnormal liver function tests, intravascular activation of coagulation, and elevated triglycerides
This is a medical emergency with significant mortality risk if not recognized and treated immediately. The guidelines emphasize that MAS treatment must include high-dose glucocorticoids, with consideration of anakinra, ciclosporin, and/or IFNγ inhibitors as part of initial therapy 1.
Why the Other Statements are Incorrect
Statement (a) - FALSE
The cervical and thoracic spine can be affected in rheumatoid arthritis. Cervical spine involvement, particularly atlantoaxial subluxation, is a well-recognized and potentially serious complication of RA that can lead to neurological compromise.
Statement (c) - FALSE
Seronegative rheumatoid arthritis absolutely exists. Approximately 20-30% of patients with RA are seronegative (negative for both rheumatoid factor and anti-CCP antibodies). These patients still meet clinical criteria for RA based on joint involvement patterns and other features.
Statement (d) - FALSE
This statement reverses the actual findings. In systemic lupus erythematosus-associated pleuritis, pleural fluid typically shows normal glucose levels. In rheumatoid arthritis pleuritis, pleural fluid characteristically shows low glucose levels (often <30 mg/dL), which is one of the distinguishing features of RA-associated pleural effusions.
Statement (e) - FALSE
Familial Mediterranean Fever (FMF) does cause arthritis. Arthritis is one of the major manifestations of FMF, typically presenting as acute monoarthritis or oligoarthritis affecting large joints (especially knees, ankles, and hips) during attacks. The arthritis is usually self-limited and non-erosive.
Clinical Implications for MAS Recognition
When evaluating a patient with juvenile idiopathic arthritis who develops concerning symptoms, actively screen for MAS by looking for:
- Persistent or worsening fever despite treatment
- Falling blood counts (particularly platelets, white blood cells, hemoglobin)
- Dramatically elevated ferritin (often >500 ng/mL, sometimes >10,000 ng/mL)
- Hepatosplenomegaly
- Elevated liver enzymes
- Coagulopathy (elevated D-dimer, low fibrinogen)
- Hypertriglyceridemia
Do not wait for all criteria to be met before initiating treatment - MAS has high mortality if treatment is delayed. The 2024 guidelines emphasize that patients should be actively screened and monitored throughout their disease course 1.