Septic Arthritis of the Hip in the Setting of Hemophagocytic Lymphohistiocytosis: A Case Report

Aeromonas veronii-induced septic arthritis of the hip in a child with acute lymphoblastic leukemia

Septic arthritis of the hip (SAH) is a prevalent form of infectious arthritis in children that can lead to serious complications if not promptly diagnosed and treated. A 6-year 4-month-old female child with a 1-year history of acute lymphoblastic leukemia chemotherapy was admitted to our hospital due to a 1-day fever. After 1 week, the child experienced right inguinal pain and exhibited severe restriction in the flexion of the right lower limb and hip. Consequently, edema was observed in the right lower extremity and foot. SAH was initially diagnosed using computed tomography and magnetic resonance imaging examinations of both hip joints. Subsequently, incision and irrigation procedure were performed on the hip joint. Following the surgery, pus metagenomic next-generation sequencing (mNGS) were conducted promptly, and the mNGS analysis indicated an Aeromonas veronii infection. The diagnosis of A. veronii SAH was subsequently confirmed through polymerase chain reaction. The child's condition was successfully treated with a combination of amikacin and imipenem-cilastatin, leading to improvement and subsequent discharge in a satisfactory state. SAH caused by A. veronii is a rare occurrence, and the utilization of mNGS holds significant potential for the early detection of uncommon infections in immunosuppressed children.

Fungal-Induced Hemophagocytic Lymphohistiocytosis: A Literature Review in Non-HIV Populations

We performed a thorough search of the literature published through December 2024 with no date exclusions on invasive fungal infection (IFI)-induced hemophagocytic lymphohistiocytosis (HLH) in non-human immunodeficiency virus (HIV) patients. The frequency of IFI-induced HLH reported across 16 articles was 9%. Of the 116 identified cases with available clinical information, 53% occurred in immunocompromised patients. IFIs were usually disseminated (76%), with Histoplasma capsulatum being the most common pathogen (51%). IFI and HLH were diagnosed simultaneously in most cases (78%). The 30-day survival rate was 64%. Reported cases had significant heterogeneity in patient characteristics, management strategies, and outcomes.

SARS-CoV-2 reactivates fungal-associated Hemophagocytic lymphohistiocytosis: Case report and review of the literature

Hemophagocytic lymphohistiocytosis (HLH) is a rare disease characterized by the uncontrolled activation of the immune system, resulting in a high clinical mortality rate. A 56-year-old Chinese female presented at the emergency room with symptoms including fever, fatigue, nausea, vomiting, cough, shortness of breath, and chest tightness. Laboratory investigations demonstrated decreased levels of white blood cells, hemoglobin, and platelets while interleukin-6 and ferritin exhibited significant elevations. She was subsequently admitted to the hematology department, where she was diagnosed with HLH caused by a Candida infection. Following treatment with antifungal agents, glucocorticoids, antiemetics, diuretics, and hepatoprotective therapy, the patient's condition has shown improvement. However, after being infected with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the patient experienced a reactivation of HLH, resulting in a more severe clinical presentation and complications compared to the initial onset. Although the patient's condition improved after the administration of antiviral drugs, etoposide, glucocorticoids, cyclosporin, and intravenous immunoglobulin, this case highlights the possibility of disease reactivation during the recovery phase of HLH. This should raise the attention of medical professionals.

CLINICAL UTILITY OF INTERLEUKIN-1 INHIBITORS IN PEDIATRIC SEPSIS

ABSTRACT

The pathophysiology of pediatric sepsis is characterized by increased innate immune activation earlier in life. Interleukin-1 is a proinflammatory cytokine implicated in the pathophysiology of sepsis, and ferritin is a stable surrogate biomarker for elevated IL-1 levels. Data in adult sepsis have shown that use of anakinra, an anti-IL-1 receptor antagonist, led to improved clinical outcomes in patients with features of macrophage activation and hyperferritinemia. However, data in pediatric sepsis are lacking. Our narrative review sought to highlight the current understanding of using IL-1 inhibitors in pediatric sepsis. We identified five studies including one case report and four retrospective case series that described clinical outcomes in relation to use of anakinra for secondary hemophagocytic lymphohistiocytosis (HLH). A few patients in this pooled heterogenous cohort of 72 patients had concomitant infection meeting the criteria for sepsis. All studies measured ferritin levels and reported a decrease in ferritin after initiating anakinra. Twelve patients died after treatment initiation. There was no clear comparison in clinical outcomes between infected and noninfected patients. The pathophysiology of pediatric sepsis suggests that there is a need for blinded clinical trials using targeted immunomodulation such as IL-1 inhibitors in pediatric sepsis cohort with an immunophenotype suggesting increased innate immune activation.

Use of Intravenous Anakinra for Management of Pediatric Cytokine Storm Syndromes at an Academic Medical Center

Background: Off-label intravenous (IV) route of anakinra is increasingly recognized to enable higher and faster maximal plasma concentrations than subcutaneous route for treatment of cytokine storm syndromes. Objective: To describe off-label indications of IV anakinra, corresponding dosing and safety profiles, particularly during the coronavirus disease 19 (COVID-19) pandemic. Methods: A retrospective, single-cohort study was conducted at an academic medical center to evaluate use of IV anakinra in hospitalized pediatric patients (age ≤21 years). Institutional Review Board review was considered exempt. The primary endpoint was the primary indication(s) for IV anakinra. The key secondary endpoints were dosing of IV anakinra, previous immunomodulatory therapies, and adverse events. Results: Of 14 pediatric patients, 8 (57.1%) received IV anakinra for treatment of multisystem inflammatory syndrome in children (MIS-C) associated with COVID-19, whereas 3 and 2 were treated for hemophagocytic lymphohistiocytosis (HLH) and flares of systemic onset juvenile idiopathic arthritis (SoJIA), respectively. The initial dosing regimen of IV anakinra for MIS-C associated with COVID-19 was a median dose of 2.25 mg/kg/dose with a median dosing interval of 12 hours for a median initial treatment duration of 3.5 days. Eleven (78.6%) patients received previous immunomodulatory therapies (IV immune globulin [n = 10; 71.4%] and steroids [n = 9; 64.3%]). No adverse drug events were documented. Conclusion: IV anakinra was used off-label for treatment of MIS-C associated with COVID-19, HLH and SoJIA flares in critically ill patients with no adverse drug events documented. This study helped ascertain the off-label indications of IV anakinra and corresponding patient characteristics.

Silencing the cytokine storm: the use of intravenous anakinra in haemophagocytic lymphohistiocytosis or macrophage activation syndrome

The term cytokine storm syndromes describes conditions characterised by a life-threatening, fulminant hypercytokinaemia with high mortality. Cytokine storm syndromes can be genetic or a secondary complication of autoimmune or autoinflammatory disorders, infections, and haematological malignancies. These syndromes represent a key area of interface between rheumatology and general medicine. Rheumatologists often lead in management, in view of their experience using intensive immunosuppressive regimens and managing cytokine storm syndromes in the context of rheumatic disorders or infection (known as secondary haemophagocytic lymphohistiocytosis or macrophage activation syndrome [sHLH/MAS]). Interleukin (IL)-1 is pivotal in hyperinflammation. Anakinra, a recombinant humanised IL-1 receptor antagonist, is licenced at a dose of 100 mg once daily by subcutaneous injection for rheumatoid arthritis, systemic juvenile idiopathic arthritis, adult-onset Still's disease, and cryopyrin-associated periodic syndromes. In cytokine storm syndromes, the subcutaneous route is often problematic, as absorption can be unreliable in patients with critical illness, and multiple injections are needed to achieve the high doses required. As a result, intravenous anakinra is used in clinical practice for sHLH/MAS, despite this being an off-licence indication and route of administration. Among 46 patients admitted to our three international, tertiary centres for sHLH/MAS and treated with anakinra over 12 months, the intravenous route of delivery was used in 18 (39%) patients. In this Viewpoint, we describe current challenges in the management of cytokine storm syndromes and review the pharmacokinetic and safety profile of intravenous anakinra. There is accumulating evidence to support the rationale for, and safety of, intravenous anakinra as a first-line treatment in patients with sHLH/MAS. Intravenous anakinra has important clinical relevance when high doses of drug are required or if patients have subcutaneous oedema, severe thrombocytopenia, or neurological involvement. Cross-speciality management and collaboration, with the generation of international, multi-centre registries and biobanks, are needed to better understand the aetiopathogenesis and improve the poor prognosis of cytokine storm syndromes.