Extracorporeal membrane oxygenation outcomes in children with hemophagocytic lymphohistiocytosis

Iatrogenic HLH

Hemophagocytic lymphohistiocytosis (HLH) can be categorized as either primary (familial, generally occurring in infants) or secondary (sHLH, occurring at any age in association with a variety of conditions) and is mainly triggered by infections, autoimmune diseases, and malignant conditions. Our understanding of the pathophysiology of sHLH is still evolving, and among the causes and associations with the syndrome, those putatively associated with iatrogenic causes remain among the most poorly understood due to the rarity of these entities and the multiple confounders so often present in the patients in whom they are reported. Herein, we present a review of the literature to describe the diagnostic and therapeutic challenges of sHLH associated with iatrogenic causes and discuss some of the challenges and future directions in our efforts to better understand these complex conditions for the advancement of patient outcomes.

Treatment and mortality of hemophagocytic lymphohistiocytosis in critically ill children: A systematic review and meta-analysis

OBJECTIVE

Risk factors of mortality in critically ill children with hemophagocytic lymphohistiocytosis (HLH) are not well described. This systematic review aims to determine overall mortality of critically ill children with HLH, and describes etiologies, treatment, and pediatric intensive care unit (PICU) support employed.

DATA SOURCES

PubMed, Embase, Web of Science, CINAHL, and Cochrane Library from inception until February 28, 2022.

STUDY SELECTION

Observational studies and randomized controlled trials reporting children aged 18 years or below, diagnosed with HLH and admitted to the PICU.

DATA EXTRACTION

Etiologies, treatment modalities, PICU therapies, and mortality outcomes were summarized. Random-effects meta-analysis was performed.

DATA SYNTHESIS

Total 36 studies (total patients = 493, mean age: 49.5 months [95% confidence interval (CI): 30.9-79.5]) were included. Pooled mortality rate was 32.6% (95% CI: 23.4-42.4). The most frequent etiologies for HLH were infections (53.3%) and primary HLH (12.8%), while the remaining cases were due to other causes of secondary HLH, including autoimmune diseases, malignancy, and drug-induced and idiopathic HLH. Pooled mortality rate was higher in primary than secondary HLH (72.2%, 95% CI: 57.8-84.5 vs. 23.9%, 95% CI: 14.4-35.02; p < .01). Univariate analysis found that treatment with etoposide was associated with higher mortality, while intravenous immunoglobulins (IVIGs) were associated with lower mortality. Conversely, multivariable analysis adjusted for etiology demonstrated no association between etoposide and IVIG use, and mortality. Twenty-one studies (total patients = 278) had detailed information on PICU therapies. Mechanical ventilation (MV), continuous renal replacement therapy, and inotropes were used in 107 (38.5%), 66 (23.7%), and 51 patients (18.3%), respectively. Need for MV was associated with increased risk of mortality (mean difference = 28%, 95% CI: 9-47).

CONCLUSION

Critically ill children with HLH have high mortality rates and require substantial PICU support. Collaborative work between multiple centers with standardized data collection can potentially provide more robust data.

Outcomes of extracorporeal life support for respiratory failure in children with primary immunodeficiencies

OBJECTIVE

Extracorporeal Membrane Oxygenation (ECMO) may serve as a life-saving rescue therapy in critically ill children with respiratory failure. While survival rates of ECMO in children with secondary immunodeficiency is considered relatively poor, survival rates in children with primary immunodeficiencies (PID) has yet to be thoroughly investigated.

DESIGN

Retrospective analysis of prospectively collected data from children (29 days-18 years old). PID patients were identified by using International Classification of Diseases (ICD) codes.

SETTING

Data were retrieved from Extracorporeal Life Support Organization Registry (1989-2018).

INTERVENTIONS

ECMO for a pulmonary support indication. The survival-to-discharge rate was calculated and factors influencing outcomes were compared between survivors and non-survivors.

MEASUREMENTS AND MAIN RESULTS

A total of 73 eligible ECMO runs were included. The survival-to-discharge rate in pediatric PID patients was 45.2%. No differences were noted in survival based on type of immunodeficiency (p = 0.42) or decade of support (p = 0.98). There was no difference in the rate of pre-ECMO infection in survivors versus non-survivors (p = 0.69). The survival-to-discharge rate in patients with a culture positive infection during the ECMO run was 45.0% versus 45.3% in those with no infection (p = 0.98). In multivariate analysis, only cardiac complications (OR 5.09, 95% CI: 1.15-22.53), pulmonary complications (OR: 13.00, 95% CI: 1.20-141.25), and neurologic complications (OR: 9.86, 95% CI: 1.64-59.21) were independently associated with increased mortality.

CONCLUSION

Children with a PID who require extracorporeal life support due to respiratory failure have a reasonable chance of survival and should be considered candidates for ECMO. The presence of a pre-ECMO infection should not be considered an ECMO contraindication.

The Use of Extracorporeal Life Support in Children With Immune-Mediated Diseases

OBJECTIVES

To describe the use and outcomes of extracorporeal membrane oxygenation support among children with immune-mediated conditions.

DESIGN

Retrospective cohort study.

SETTING

The Extracorporeal Life Support Organization registry.

PATIENTS

Patients 1 month to 18 years old with International Classification of Diseases, 9th Edition and International Classification of Diseases, 10th Edition codes for immune-mediated conditions from 1989 to 2018.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

During the study period, 207 patients with an immune-mediated condition received extracorporeal membrane oxygenation, and 50% survived to discharge. Most patients (63%) received extracorporeal membrane oxygenation for respiratory support with 53% survival, 21% received cardiac support (55% survival), and 15% received extracorporeal cardiopulmonary resuscitation (34% survival). The most common diagnosis among nonsurvivors was hemophagocytic lymphohistiocytosis/macrophage activation syndrome with 37% survival. Patients with juvenile idiopathic arthritis (23%) and dermatomyositis (25%) had the lowest survival. Nonsurvivors had a higher frequency of infections, neurologic complications, and renal replacement therapy use. Use of preextracorporeal membrane oxygenation corticosteroids was associated with mortality.

CONCLUSIONS

Children with immune-mediated conditions can be successfully supported with extracorporeal membrane oxygenation. Extracorporeal membrane oxygenation use has increased over time, and survival varies considerably by diagnosis.

Consensus-Based Guidelines for the Recognition, Diagnosis, and Management of Hemophagocytic Lymphohistiocytosis in Critically Ill Children and Adults

OBJECTIVE

Hemophagocytic lymphohistiocytosis is a hyperinflammatory syndrome that often requires critical care support and remains difficult to diagnose. These guidelines are meant to aid in the early recognition, diagnosis, supportive care, and treatment of patients with hemophagocytic lymphohistiocytosis in ICUs.

DATA SOURCES

The literature searches were performed with PubMed (MEDLINE).

STUDY SELECTION

Keywords and medical subject headings terms for literature search included "macrophage activation syndrome," hemophagocytic lymphohistiocytosis," and "hemophagocytic syndrome."

DATA EXTRACTION

The Histiocyte Society developed these consensus recommendations on the basis of published reports and expert opinions with level of evidence provided for each recommendation. They were endorsed by the Society of Critical Care Medicine.

DATA SYNTHESIS

Testing for hemophagocytic lymphohistiocytosis should be initiated promptly in all patients admitted to ICUs with an unexplained or disproportionate inflammatory response, especially those with rapid clinical deterioration. Meeting five or more of eight hemophagocytic lymphohistiocytosis 2004 diagnostic criteria serves as a valuable diagnostic tool for hemophagocytic lymphohistiocytosis. Early aggressive critical care interventions are often required to manage the multisystem organ failure associated with hemophagocytic lymphohistiocytosis. Thorough investigation of the underlying triggers of hemophagocytic lymphohistiocytosis, including infections, malignancies, and autoimmune/autoinflammatory diseases, is essential. Early steroid treatment is indicated for patients with familial hemophagocytic lymphohistiocytosis and is often valuable in patients with acquired hemophagocytic lymphohistiocytosis (i.e., secondary hemophagocytic lymphohistiocytosis) without previous therapy, including macrophage activation syndrome (hemophagocytic lymphohistiocytosis secondary to autoimmune/autoinflammatory disease) without persistent or relapsing disease. Steroid treatment should not be delayed, particularly if organ dysfunction is present. In patients with macrophage activation syndrome, whose disease does not sufficiently respond, interleukin-1 inhibition and/or cyclosporine A is recommended. In familial hemophagocytic lymphohistiocytosis and severe, persistent, or relapsing secondary macrophage activation syndrome, the addition of prompt individualized, age-adjusted etoposide treatment is recommended.

CONCLUSIONS

Further studies are needed to determine optimal treatment for patients with hemophagocytic lymphohistiocytosis in ICUs, including the use of novel and adjunct therapies.

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.

Two Brothers with Atypical UNC13D-Related Hemophagocytic Lymphohistiocytosis Characterized by Massive Lung and Brain Involvement

Hemophagocytic lymphohistiocytosis (HLH) is a potentially fatal hyperinflammatory condition. Variants in different genes have been associated with the familial forms of the syndrome (FHL), usually presenting within the first 2 years of life. Due to increasing awareness of the signs and symptoms of HLH and a better understanding of the genetic basis of the disease, FHL has been increasingly diagnosed in patients presenting beyond infancy. Here, we report on two brothers with atypical, late-onset HLH in which whole exome sequencing revealed a homozygous pathogenic UNC13D variant. In the first brother, the clinical phenotype was dominated by a massive lung involvement. In the second brother a progressive neurological deterioration was observed. In both cases, the clinical manifestations at symptom onset were misleading, making the diagnosis difficult to achieve. This report expands the spectrum of clinical presentations of FLH3. Moreover, it highlights the importance to warn clinicians to keep a high level of suspicion in patients presenting with fever, cytopenia, splenomegaly of unknown origin, and unresponsiveness to conventional treatment even beyond early childhood. Moreover, this report emphasizes that insidious neurologic symptoms may represent the initial or sole presenting sign of FHL, even in the absence of peripheral signs of activation.