An Evidence-Based Guideline Improves Outcomes for Patients With Hemophagocytic Lymphohistiocytosis and Macrophage Activation Syndrome

[Hemophagocytic lymphohistiocytosis and macrophage activation syndrome : A multidisciplinary challenge]

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome that is characterized by hyperferritinemia, cytopenia, disseminated intravascular coagulopathy and functional disorders of the liver and the central nervous system. The term macrophage activation syndrome is predominantly used for secondary HLH in the context of autoimmune diseases (e.g., systemic juvenile idiopathic arthritis). In addition, malignancies and genetic inborn errors of immunity can predispose to the development of HLH. Infections (e.g., Epstein-Barr virus) in turn represent possible triggers of an acute episode. Due to the unspecific manifestation of the disease, a systematic evaluation of the organ systems is recommended in the clinical and laboratory analytical clarification of hyperinflammatory syndromes. In general, the treatment should be carried out by a multidisciplinary team with expertise in rheumatology, hematological oncology, infectious diseases and intensive care medicine. The primary treatment of HLH usually consists of glucocorticoids and in cases of a rapid deterioration of the condition anakinra (interleukin 1 block) and intravenous immunoglobulins can be employed. Treatment of the underlying disease should be consequently carried out in parallel, together with antimicrobial treatment.

Diagnosis and investigation of suspected haemophagocytic lymphohistiocytosis in adults: 2023 Hyperinflammation and HLH Across Speciality Collaboration (HiHASC) consensus guideline

Haemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory syndrome characterised by persistently activated cytotoxic lymphocytes and macrophages, which, if untreated, leads to multiorgan dysfunction and death. HLH should be considered in any acutely unwell patient not responding to treatment as expected, with prompt assessment to look for what we term the three Fs-fever, falling blood counts, and raised ferritin. Worldwide, awareness of HLH and access to expert management remain inequitable. Terminology is not standardised, classification criteria are validated in specific patient groups only, and some guidelines rely on specialised and somewhat inaccessible tests. The consensus guideline described in this Health Policy was produced by a self-nominated working group from the UK network Hyperinflammation and HLH Across Speciality Collaboration (HiHASC), a multidisciplinary group of clinicians experienced in managing people with HLH. Combining literature review and experience gained from looking after patients with HLH, it provides a practical, structured approach for all health-care teams managing adult (>16 years) patients with possible HLH. The focus is on early recognition and diagnosis of HLH and parallel identification of the underlying cause. To ensure wide applicability, the use of inexpensive, readily available tests is prioritised, but the role of specialist investigations and their interpretation is also addressed.

Implementing a Disease-specific Multidisciplinary Team and Order Set for Hemophagocytic Lymphohistiocytosis in a Pediatric Hospital

OBJECTIVE

To improve outcomes of hemophagocytic lymphohistiocytosis (HLH), prompt recognition and treatment are necessary. A HLH multidisciplinary team was implemented at our institution, and we established an electronic order set to foster uniformity in the diagnostic approach. The goal of this study is to capture the impact of this diagnostic tool.

METHODS

This is a retrospective study analyzing the utilization of a HLH-specific order set since time of implementation in June 2019 through December 2022. The trends in the utilization of the order set by providers were analyzed to evaluate the awareness and effectiveness of this tool.

RESULTS

The order set was utilized 50 times, most commonly by hematology/oncology (50%) and infectious disease (26%). Utilization by providers on newly presenting patients included 4 times in the year 2019, 12 times in 2020, 16 times in 2021, and 18 times in 2022. Utilization was associated with the diagnosis of HLH in 9 patients (18%).

CONCLUSION

Implementation of an HLH-specific order set facilitated a systematic method to approach patients with suspected HLH. The utilization of the order set displayed an upward trend over time, indicating support of this tool among these providers. This tool can increase awareness and early identification of HLH.