Pediatric Hemophagocytic Lymphohistiocytosis: Formation of an Interdisciplinary HLH Working Group at a Single Institution.

Fever of unknown origin is a common presentation in children with an extensive differential diagnosis that encompasses multiple specialties. From a hematologic standpoint, the differential includes hyperinflammatory syndrome, such as hemophagocytic lymphohistiocytosis (HLH), among others. Due to the rarity of HLH and nonspecific symptoms at initial presentation, specialists are often consulted later in the disease progression, which complicates disease evaluation further. Cook Children's Medical Center (CCMC) has recently developed a multidisciplinary histiocytic disorder group that is often consulted on cases presenting with fever of unknown origin to increase awareness and potentially not miss new HLH cases. In this study, we examine the clinical presentation and workup of 13 patients consulted by the HLH work group at a single institution and describe the clinical course of 2 patients diagnosed with HLH. The goal of this project was to describe the formation of a disease-specific team and the development of a stepwise diagnostic approach to HLH. A review of the current diagnostic criteria for HLH may be warranted given findings of markers such as soluble IL2 receptor and ferritin as nonspecific and spanning multiple disciplines including rheumatology, infectious disease, and hematology/oncology.

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.

Distal extremity necrosis as a manifestation of cutaneous polyarteritis nodosa: case report and review of the acute management of a pediatric patient.

We present the case of an 8-year-old girl who presented with distal extremity necrosis of the hands, feet, nose, and ears as an acute manifestation of cutaneous polyarteritis nodosa (CPAN). She was emergently managed with intravenous steroids, nifedipine, sildenafil, pentoxifylline, nitroglycerin paste, aspirin, low-molecular-weight heparin, and intravenous gamma globulin. The necrosis was controlled, and reperfusion was attained to salvage the extremities. It is important for clinicians to be aware that acute distal extremity necrosis can be a manifestation of CPAN in children. Etiology is often not clear on presentation, but once infection is excluded, acute management with systemic steroids and systemic vasodilators is indicated regardless of the cause. Iloprost and bosentan may represent options for adjunctive vasodilators. More studies are needed to create guidelines for the acute and long-term management of these children. Close follow-up of children with CPAN, especially with a history of vaso-occlusive symptoms, is important to allow prompt intervention in the event of distal extremity infarction.

Childhood polyarteritis nodosa presenting with central nervous system manifestations and the posterior reversible encephalopathy syndrome.

Polyarteritis nodosa is a systemic necrotizing vasculitis involving medium-sized muscular arteries. Polyneuropathy is the only neurologic manifestation included in the pediatric classification schema. Central nervous system manifestations include infarction, hemorrhage, and encephalitis. We report on a 13-year-old female whose initial presentation of polyarteritis nodosa included hypertension, seizures, and neuroimaging findings of vasogenic edema and posterior reversible encephalopathy syndrome. Posterior reversible encephalopathy syndrome has been reported in association with renal disease, transplantation, autoimmunity, and cytotoxic medications. Posterior reversible encephalopathy syndrome outcomes are usually favorable with supportive care and treatment of the underlying etiology. The patient's neurologic condition improved after treatment of hypertension. Hypertension, posterior reversible encephalopathy syndrome, and abdominal pain led to a diagnostic workup. A systemic vasculitis was confirmed after detection of a perinephric hematoma and intrarenal aneurysms. This is a novel case of posterior reversible encephalopathy syndrome as an initial manifestation of pediatric polyarteritis nodosa.

Takayasu arteritis presenting as severe ascending aortic arch dilation and aortic regurgitation in a 10-year-old female.

Takayasu arteritis (TA) is a large-vessel arteritis affecting the aorta and its major branches. It is a rare disease in children less than 10 years old, and its diagnosis is frequently delayed, likely because of TA's rarity and nonspecific symptoms early in the disease. Females are affected disproportionately, with a female to male ratio of 8.5 to 1. Recently, the European League against Rheumatism published an international consensus statement for making the diagnosis of childhood TA. Criteria include angiographic abnormalities of the aorta and/or its branches, pulse deficit or claudication, blood pressure discrepancy, bruits, hypertension, and elevated acute phase reactants. We described a 10-year-old female with severe TA of the ascending aorta and who presented with classic signs and symptoms of this rare disease.