Introduction: Hemophagocytic lymphohistiocytosis (HLH)/Macrophage activation syndrome (MAS) is a life-threatening condition if not diagnosed and treated effectively. The condition is characterized by an uncontrolled hyperinflammatory response which is often triggered by infections/malignancy or connective tissue disorders. Familial types result from genetic defects in natural killer cells and cytotoxic T-cells, typically affecting perforin and intracellular vesicles. HLH is likely under-recognized which contributes to its high morbidity and mortality. Early recognition and effective therapy is crucial for cure.

Methodology: We conducted a literature review and developed an evidence-based practice protocol following the KSUMC Evidence-Based Guidelines and Protocols Program. The protocol was revised with input from key stakeholders to align with the needs of our academic healthcare center. This approach has significantly improved the morbidity and mortality of pediatric patients with HLH.

Results:

• Boston Children’s Hospital Result’s: After the EBG launch in, 17 patients were diagnosed with MAS-HLH by the treating team. Of these 94% met criteria for MAS. There was a statistically significant reduction in mortality from 50% before implementation of the EBG to 6% in the post-EBG cohort (P = 0.02). There was a significant improvement in time to 50% reduction in C-reactive protein level in the post-EBG vs pre-EBG cohorts (log-rank P < 0.01). There were trends toward faster time to MAS-HLH diagnosis, faster initiation of immunosuppressive therapy, shorter length of hospital stay, and more rapid normalization of MAS HLH–related biomarkers in the patients post-EBG.
• Initial KSUMC Results: After the EBG launch in, nine children were confirmed to be HLH/MAS as per KSUMC HLH/MAS criteria , of those the survival rate was 88.9 %. The one death was mostly due to refractory/relapsed ALL. Time to reach the diagnosis was 6-13 days of admission, response to treatment started around 2-3 days of treatment. Treatment was tailored as per the protocol, most of cases received IVIG, anakinra and prednisolone.