Reactive hemophagocytic syndrome presenting as a component of multiple organ dysfunction syndrome.

OBJECTIVE: To report two cases of severe reactive hemophagocytic syndrome (RHS), to discuss their impact, and to present evidence that RHS may be a constitutive part of multiple organ dysfunction syndrome (MODS).
DESIGN: Case-report.
SETTING: Pediatric intensive care unit (PICU). PATIENTS: Two patients with RHS and MODS.
INTERVENTIONS: None.
MEASUREMENTS AND MAIN RESULTS: Case #1: A 3 yr-old boy with Mucha-Haberman syndrome (pityriasis lichenoides) was admitted to the PICU for septic shock, acute respiratory distress syndrome, capillary leak, acute renal failure, liver dysfunction, and RHS (pancytopenia and hemophagocytosis on bone marrow aspirate). The pancytopenia was severe (white blood cell count, 0.9 x 10(9)/L; hemoglobin, 59 g/L; platelets, 36 x 10(9)/L), required many transfusions, and resolved 2 months later. The patient needed mechanical ventilation for 6 wks. Length of stay in PICU was 2 months. Case #2: A previously healthy 4 yr-old girl was admitted to the PICU for respiratory failure. She developed acute respiratory distress syndrome, cardiomyopathy with complete atrioventricular block, shock, capillary leak, liver dysfunction, and RHS (pancytopenia and hemophagocytosis on bone marrow aspirate). The pancytopenia was severe (white blood cell count, 1.92 x 10(9)/L; hemoglobin, 65 g/L; platelets, 58 x 10(9)/L) and necessitated transfusional support. Serology for respiratory syncytial virus was positive. RHS duration was 20 days; the patient recovered completely. Length of mechanical ventilation was 16 days and length of stay in PICU was 3 wks.
CONCLUSIONS: These cases show that RHS may be a significant cause of pancytopenia in the PICU. It needs to be recognized as a clinical entity because it can be reversible and nonneoplastic. RHS and MODS share some pathophysiologic elements and could be related to each other.