ICU Outcomes of Pediatric HLH by Subtype: A 10-Year Single-Center Cohort Study

Monday, March 23, 2026

11:30 AM - 12:30 PM Central Time

Location: Connections Central - RST 04

Carlos R. Vargas, MD (he/him/his)

Baylor College of Medicine Texas Children's Hospital, Texas

Disclosure(s): No relevant financial relationship(s) to disclose.
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Dalia A. Bashir, MD

Assistant Professor of Pediatrics
Baylor College of Medicine/ Texas Children's Hospital

Disclosure information not submitted.
Fong W. Lam, Non-Member Physician (he/him/his)

Baylor College of Medicine, Texas

Disclosure information not submitted.
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Olive Eckstein, MD

Dr.
Baylor College of Medicine Texas Children's Hospital

Disclosure information not submitted.
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Saleh Bhar, MD

Dr.
Baylor College of Medicine Texas Children's Hospital

Disclosure information not submitted.

Introduction: Hemophagocytic lymphohistiocytosis (HLH) is a life threatening hyperinflammatory syndrome with high ICU mortality. Pediatric outcome data stratified by HLH subtype is limited. We hypothesized that subtypes differ in mortality and ICU resource utilization.

Methods: We conducted a retrospective review of pediatric HLH patients admitted to a quaternary care ICU from 2014–2024. HLH subtypes included familial, infection associated, rheumatologic, malignancy associated, solid organ transplant, immunodeficiency, or idiopathic. Data collected included use of invasive mechanical ventilation (IMV), renal replacement therapy (RRT), ECMO, ICU and hospital LOS, and hospital mortality.

Results: A total of 253 patients with HLH were identified, 128 had ICU admissions and comprised the study cohort. Some patients met criteria for multiple subtypes. Overall hospital mortality was 30% (38/128). By subtype: familial 25% (10/32), infection associated 31% (22/70; EBV 8/26, CMV 3/6, other infections 11/38), rheumatologic 8% (2/24), malignancy associated 36% (9/25), solid organ transplant 40% (2/5), immunodeficiency 21% (3/14), idiopathic 30% (3/10). IMV was required in 60% (77 patients), highest in malignancy associated (72%, 18/25) and infection associated (64%, 45/70). RRT was used in 30% (39 patients), most frequency in solid organ transplant (80%, 4/5) and infection associated HLH (41%, 29/70). IMV and RRT use by subtype: Familial HLH (53% IMV, 25% RRT); rheumatologic (38% IMV, 21% RRT); immunodeficiency (64% IMV, 29% RRT); idiopathic (70% IMV, 20% RRT). ECMO was used in 5 patients: 2 on VV ECMO (infectious HLH, both survived) and 3 on VA ECMO (1 rheumatologic survived; 2 infectious, 1 survived). Median ventilator days: 13 (IQR 6–25), RRT days: 21 (IQR 11–37), ICU LOS: 14 days (IQR 4–31.5), hospital LOS: 41 days (IQR 21–72.5).

Conclusions: In this 10-year pediatric ICU cohort, HLH mortality and resource utilization varied by subtype. Malignancy associated, familial, and infection associated HLH had the highest mortality while rheumatologic HLH had the lowest. Differences in mechanical support patterns suggest a role for subtype-specific prognostication and ICU management strategies.