Outcomes Analysis of Children Diagnosed With Hemophagocytic Lymphohistiocytosis in the PICU

Objectives: Describe a single center experience of hemophagocytic lymphohistiocytosis in a PICU over a 10-year period, to identify clinical features that may be associated with worse outcomes, including mortality, hospital and ICU length of stay, and functional and cognitive impairments on discharge. Design: Retrospective electronic medical record review, 2007–2017. Setting: PICU located in a large urban academic quaternary care children’s hospital. Patients: All children admitted with hemophagocytic lymphohistiocytosis to our PICU from 2007 to 2017. Interventions: None. Measurements and Main Results: All patients were identified utilizing International Classification of Diseases , 9th Revision and International Classification of Diseases , 10th Revision codes. Each chart was reviewed for demographic information, hemophagocytic lymphohistiocytosis diagnostic criteria, laboratory data, Pediatric Risk of Mortality Score III, clinical features and events of ICU stay, and PICU and hospital (length of stay). Mortality at 1 year and change in Functional Status Scale from admission to discharge were recorded. There were 42 admissions with 33 unique patients. Median Pediatric Risk of Mortality score at admission was 9 (interquartile range, 7–16). Median PICU length of stay was 7 days (interquartile range, 2–21 d) and hospital length of stay was 24 days (interquartile range, 14–37 d). During their ICU stay, 56% of patients received mechanical ventilation, 43% required vasoactives, 18% required continuous renal replacement therapy, and 5% received extracorporeal life support. Clinical factors related to increased PICU length of stay included Pediatric Risk of Mortality III score ( p = 0.019), maximum lactate dehydrogenase ( p = 0.017), maximum total bilirubin ( p = 0.042), need for mechanical ventilation ( p = 0.002), vasoactive use ( p = 0.02), and secondary infection ( p = 0.007). The most common therapies for hemophagocytic lymphohistiocytosis included steroids (93%), etoposide (55%), and anakinra (48%). Of the 26 patients who survived to hospital discharge, 19% had newly acquired morbidities. Overall 1-year mortality was 42%. Conclusions: Hemophagocytic lymphohistiocytosis diagnosed in the PICU is a disease with high mortality. Patients who survive to discharge had relatively little morbidity, however, the mortality risk in the year following discharge continued to remain high.