Description

Minoia et al reported the MS score for the macrophage activation syndrome (MAS) in a patient with systemic juvenile idiopathic arthritis (sJIA). This can help to distinguish MAS from active sJIA. The authors are from the Pediatric Rheumatology International Trials Organization, the Childhood Arthitis & Rheumatology Research Alliance, the Pediatric Rheumatology Collaborative Study Group and the Histiocyte Society.


Patient selection: systemic juvenile idiopathic arthritis (sJIA)

 

Parameters:

(1) CNS involvement

(2) hemorrhagic manifestations (petechiae, ecchymoses, purpura, mucosal or GI bleeding)

(3) arthritis

(4) platelet count in 10^9/L

(5) serum LDH in U/L

(6) plasma fibrinogen in mg/dL

(7) serum ferritin in ng/mL

 

Parameter

Finding

Points

CNS involvement

no

0

 

yes

2.44

hemorrhagic manifestations

no

0

 

yes

1.54

active arthritis

no

0

 

yes

-1.3

platelet count

 

-0.003 * (PC)

serum LDH

 

0.001 * (LDH)

plasma fibrinogen

 

-0.004 * (fibrinogen)

serum ferritin

 

0.0001 * (ferritin)

 

MS score =

= SUM(points for all 7 parameters)

 

Interpretation:

Scores in the study ranged from -8.4 to 41.8.

A score >= -2.1 is associated with MAS.

 

Performance:

The sensitivity was 0.85 and specificity 0.95.

The area under the ROC curve is 0.95.


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