Table 4 Early diagnostic tools in MAS complicating sJIA

- Progressive increase in serum ferritin is a valuable laboratory marker showing the largest change in both pre-MAS and MAS-onset values (often > 10,000 ng/mL)

- Dropping ESR levels helps to distinguish MAS from a flare of the underlying rheumatic disorder (where ESR is usually elevate (a drop in ESR or a disproportion between ESR and CRP levels would raise the suspicion of MAS))

- As some patients may have basic elevated serum ferritin levels especially with repeated blood transfusions, a progressive increase in serum ferritin from the basic level for these patients would be suggestive of MAS particularly if it was associated with a decrease of ESR

- Relative decrease in platelet count followed by a decrease in WBCs, or fibrinogen levels rather than an absolute decrease, may be more useful in making an early diagnosis of MAS and differentiate MAS from sJIA flare

- Hemophagocytosis in bone marrow examination is pathognomonic, but failure to reveal hemophagocytosis does not exclude the diagnosis of MAS as histopathologic features of hemophagocytosis may not be present in the initial stages

3

B

8.26 ± 1.7

95.65

H