Rheumatology
From a rheumatologic perspective, all patients in our cohort had active
sJIA disease; 89% of participants had a history of macrophage
activation syndrome (MAS), with 33% having MAS recently before their
diagnosis of sJIA-LD. History of MAS, particularly recurrent episodes of
MAS, is also a common finding in other sJIA-LD cohorts2, 6, 10. Our patients showed elevations in
inflammatory cytokines, specifically IL-18, which has also been seen in
other studies. IL-18 elevation has been implicated as a marker of sJIA
disease activity, development of MAS, and in sJIA patients with
pulmonary alveolar proteinosis 12,13. Other laboratory
trends include a prodrome of lymphopenia, ferritin, and peripheral
eosinophilia 9. These trends hint at sJIA-LD’s
underlying pathophysiology, but further investigation is needed. Common
clinical features identified in previous cohorts included
lymphadenopathy and hepatosplenomegaly 6, 10. However,
these were not identified in our patient population.
Saper, et al. identified several patients with delayed drug
hypersensitivity in their case series 9. They noted a
high frequency of anaphylactic reactions to the interleukin (IL)-6
inhibitor, tocilizumab. In a cohort of 25 cases, 68% of patients were
taking a biologic disease-modifying antirheumatic drugs; two subsequent
cohorts likewise observed a higher number of adverse effects related to
anti-cytokine drugs 6, 9, 10. As previously mentioned,
all patients in our case series were treated with anakinra (an IL-1
inhibitor). Five patients also received IL-6 inhibitor tocilizumab; one
patient received IL-1β inhibitor canakinumab. In our case series, one of
the four patients treated with tocilizumab developed confirmed DRESS. No
other treatment was associated with DRESS. No patients developed
anaphylaxis following use of tocilizumab.
Interestingly, five out of nine patients initially presented with
symptoms concerning Kawasaki disease. This highlights the importance of
keeping sJIA on the initial
differential and completing early evaluation if other aspects of the
clinical course are not consistent with Kawasaki disease. There is no
current evidence that treatment for Kawasaki disease (such as steroids,
IVIG, and infliximab) precipitates interstitial lung disease.