Extracorporeal Membrane Oxygenation for Hemophagocytic Lymphohistiocytosis

Adjustments to pharmacologic therapies for hemophagocytic lymphohistiocytosis while on extracorporeal support

Hemophagocytic lymphohistiocytosis (HLH) is an immune dysregulatory syndrome characterized by severe inflammation and end-organ damage. Due to significant organ dysfunction, patients often require extracorporeal membrane oxygenation (ECMO) and continuous renal replacement therapy (CRRT). In this report, we describe consideration for adjusting treatment in the context of extracorporeal organ support. We describe agents commonly used and dosing adjustments made in light of extracorporeal organ support. We report six cases that illustrate the feasibility of initiating standard HLH therapies in patients requiring these modalities.

Macrophage activating syndrome causing decompensated right heart failure

Background

Macrophage activating syndrome (MAS) is a form of hemophagocytic lymphohistiocytosis (HLH), a rare complication of autoimmune disease that is characterized by cytokine storm and multiorgan failure.

Case summary

A 32-year-old male presented with acutely decompensated pulmonary arterial hypertension and right heart failure secondary to MAS. The patient was immediately started on inhaled and intravenous epoprostenol, vasopressors and dexamethasone and anakinra were administered. Despite the therapies given, the patient's condition continued to decline, and he was placed on veno-arterial extracorporeal membrane oxygenation (VA-ECMO) support. Over a few days, his clinical condition improved, and he was decannulated from VA-ECMO and later transitioned oral treprositinil and was discharged home. Due to its non-specific clinical manifestations, the diagnosis of MAS depends on high clinical suspicion and initial laboratory work up such as thrombocytopenia, transaminitis, hyperferritinemia, hypertriglyceridemia, hypofibrinogenemia, etc. In our patient, MAS led to decompensated Pulmonary Arterial Hypertension (PAH) leading to right heart failure that was refractory to inhaled and intravenous epoprostenol and vasopressors and required VA-ECMO as a bridge to recovery while his MAS was managed by anakinra and dexamethasone.

Conclusion

MAS can result in acute decompensation of PAH and right heart failure. Besides RV failure management, immunosuppressants such as anakinra, etoposide, etc. should be utilized early in the management of MAS. In refractory right heart failure, VA-ECMO can be considered as a bridge to recovery. There is a paucity of literature supporting the utilization of VA-ECMO in the management of refractory right heart failure caused by MAS in adults and much of the data stems from pediatric studies. This case serves as a fine example of successful use of VA-ECMO in adult population.

Haemophagocytic lymphohistiocytosis in adult critical care

Haemophagocytic lymphohistiocytosis (HLH) is a syndrome of severe immune dysregulation, characterised by extreme inflammation, fever, cytopaenias and organ dysfunction. HLH can be triggered by conditions such as infection, autoimmune disease and malignancy, among others. Both a familial and a secondary form have been described, the latter being increasingly recognised in adult patients with critical illness. HLH is difficult to diagnose, often under-recognised and carries a high mortality. Patients can present in a very similar fashion to sepsis and the two syndromes can co-exist and overlap, yet HLH requires specific immunosuppressive therapy. HLH should be actively excluded in patients with presumed sepsis who either lack a clear focus of infection or who are not responding to energetic infection management. Elevated serum ferritin is a key biomarker that may indicate the need for further investigations for HLH and can guide treatment. Early diagnosis and a multidisciplinary approach to HLH management may save lives.