Acute encephalopathy as a primary manifestation of haemophagocytic lymphohistiocytosis

Central Nervous System Involvement of Hemophagocytic Lymphohistiocytosis: When 18F-FDG PET/CT Solves a Complex Diagnostic Investigation

ABSTRACT

Hemophagocytic lymphohistiocytosis is rare life-threatening syndrome, hereditary or acquired, mainly affecting children. Hemophagocytic lymphohistiocytosis is an immune deficiency characterized by severe inflammation caused by uncontrolled proliferation of activated lymphocytes and macrophages. The usual biological and clinical data may associate polyadenopathy, hepatosplenomegaly, fever, multivisceral damages, and cytopenias with potential multiorgan dysfunction and death. We report the case of a 4-year-old girl, hospitalized for recurrent cerebellar symptoms (ataxia) associated later with fever and pancytopenia. 18F-FDG PET/CT revealed a node pathological uptake, which was biopsied and confirmed a diagnosis of hemophagocytic lymphohistiocytosis.

MRI findings of central nervous system involvement in children with haemophagocytic lymphohistiocytosis: correlation with clinical biochemical tests

AIM

To investigate the brain magnetic resonance imaging (MRI) features of children with haemophagocytic lymphohistiocytosis (HLH) with central nervous system (CNS) involvement, and to investigate the correlation with clinical biochemical tests.

MATERIAL AND METHODS

Clinical and MRI data were collected from 118 children with HLH-CNS between January 2012 and June 2019. Patients were grouped according to their MRI findings, and statistical methods were used to test for correlations between the MRI findings and biochemical variables.

RESULTS

Patients were divided into three groups, including normal appearance (Group 1, 17/118), diffuse parenchymal volume loss (Group 2, 44/118), and brain parenchyma lesions (Group 3, 57/118) containing three subtypes of brain lesions and HLH-CNS complications. Comparing biochemical values among the three groups revealed a significant difference for all values (p<0.05), except for cell counts in the cerebrospinal fluid (CSF). A pairwise comparison further showed significant inter-group differences for most of the variables. Spearman's rank correlation coefficient also demonstrated that CSF cell counts (r=0.193, p=0.036), CSF microprotein content (r=0.379, p<0.001), serum aspartate aminotransferase (AST; r=0.521, p<0.001), serum lactate dehydrogenase (LDH; r=0.514, p<0.001) and activated partial thromboplastin time (APTT; r=0.326, p<0.001) correlated positively with the MRI groups, while platelet count (PLT; r=-0.633, p<0.001) and plasma fibrinogen (FIB; r=-0.258, p=0.005) correlated negatively.

CONCLUSION

Classification of brain MRI findings of HLH-CNS correlates well with the results of several key biochemical tests. Brain MRI is a promising method to elucidate illness severity and clinical outcomes.

Neuroinflammatory Disease as an Isolated Manifestation of Hemophagocytic Lymphohistiocytosis

Isolated neuroinflammatory disease has been described in case reports of familial hemophagocytic lymphohistiocytosis (FHL), but the clinical spectrum of disease manifestations, response to therapy and prognosis remain poorly defined. We combined an international survey with a literature search to identify FHL patients with (i) initial presentation with isolated neurological symptoms; (ii) absence of cytopenia and splenomegaly at presentation; and (iii) systemic HLH features no earlier than 3 months after neurological presentation. Thirty-eight (20 unreported) patients were identified with initial diagnoses including acute demyelinating encephalopathy, leukoencephalopathy, CNS vasculitis, multiple sclerosis, and encephalitis. Median age at presentation was 6.5 years, most commonly with ataxia/gait disturbance (75%) and seizures (53%). Diffuse multifocal white matter changes (79%) and cerebellar involvement (61%) were common MRI findings. CSF cell count and protein were increased in 22/29 and 15/29 patients, respectively. Fourteen patients progressed to systemic inflammatory disease fulfilling HLH-2004 criteria at a mean of 36.9 months after initial neurological presentation. Mutations were detected in PRF1 in 23 patients (61%), RAB27A in 10 (26%), UNC13D in 3 (8%), LYST in 1 (3%), and STXBP2 in 1 (3%) with a mean interval to diagnosis of 28.3 months. Among 19 patients who underwent HSCT, 11 neurologically improved, 4 were stable, one relapsed, and 3 died. Among 14 non-transplanted patients, only 3 improved or had stable disease, one relapsed, and 10 died. Isolated CNS-HLH is a rare and often overlooked cause of inflammatory brain disease. HLH-directed therapy followed by HSCT seems to improve survival and outcome.

Recommendations for the Use of Etoposide-Based Therapy and Bone Marrow Transplantation for the Treatment of HLH: Consensus Statements by the HLH Steering Committee of the Histiocyte Society

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome requiring aggressive immunosuppressive therapy. Following 2 large international studies mainly targeting pediatric patients with familial disease and patients without underlying chronic or malignant disease, the HLH-94 protocol is recommended as the standard of care when using etoposide-based therapy by the Histiocyte Society. However, in clinical practice, etoposide-based therapy has been widely used beyond the study inclusion criteria, including older patients and patients with underlying diseases (secondary HLH). Many questions remain around these extended indications and published reports do not address several practical issues. To tackle these concerns, the HLH Steering Committee of the Histiocyte Society decided to issue guidance for use of the HLH-94 protocol. The group convened in a structured consensus finding process to define recommendations that are based largely on expert opinion backed up by available data from the literature. The recommendations address all main elements of HLH-94 including corticosteroids, cyclosporin, etoposide, intrathecal therapy, and hematopoietic stem cell transplantation (HSCT) and consider various forms of HLH and all age groups. Aspects covered include indications, applications, dosing, side effects, duration of therapy, salvage therapy, and HSCT. These recommendations aim to provide a framework to guide treatment decisions in this severe disease.

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.

Immune-Mediated Diseases of the Central Nervous System: A Specificity-Focused Diagnostic Paradigm

Immune-mediated diseases of the central nervous system show wide variability both symptomatically and with respect to underlying pathophysiology. Recognizing aberrant immunologic activity as the cause of neurologic dysfunction requires establishing as precise a neuroanatomic and functional phenotype as possible, and a diagnostic and therapeutic strategy that stabilizes the patient, excludes broad categories of disease via rapidly available diagnostic assays, and maintains a broad differential diagnosis that includes immune-mediated conditions. This process is aided by recognizing the appropriate clinical circumstances under which immune-mediated disease should be suspected, and how to differentiate these conditions from other causes of similar neurologic dysfunction.

How to Treat Involvement of the Central Nervous System in Hemophagocytic Lymphohistiocytosis?

OPINION STATEMENT

Central nervous system (CNS)-hemophagocytic lymphohistiocytosis (HLH) is not a disease in itself, but it is part of a systemic immune response. The vast majority of patients with CNS-HLH also have systemic HLH and a large number of patients with primary and secondary HLH have CNS involvement. Reactivations within the CNS are frequent during the course of HLH treatment and may occur concomitant with or independent of systemic relapses. It is also important to consider primary HLH as an underlying cause of "unknown CNS inflammation" as these patients may present with only CNS disease. To initiate proper treatment, a correct diagnosis must be made. A careful review of the patient's history and a thorough neurological examination are essential. In addition to the blood tests required to make a diagnosis of HLH, a lumbar puncture with cerebrospinal fluid (CSF) analysis and magnetic resonance imaging (MRI) should always be done in all cases regardless of the presence or absence of neurological signs or symptom. Treatment options for CNS-HLH include, but are not limited to, those commonly used in systemic HLH, including corticosteroids, etoposide, cyclosporine A, alemtuzumab, and ATG. In addition, intrathecal treatment with methotrexate and corticosteroids has become a standard care and is likely to be beneficial. Therapy must be initiated without inappropriate delay to prevent late effects in HLH. An interesting novel approach is an anti-IFN-gamma antibody (NI-0501), which is currently being tested. Hematopoietic stem cell transplantation (HSCT) also represents an important CNS-HLH treatment; patients with primary HLH may benefit from immediate HSCT even if there is active disease at time of transplantation, though care should be taken to monitor CNS inflammation through HSCT and treat if needed. Since CNS-HLH is a condition leading to the most severe late effects of HLH, early expert consultation is recommended.

Adult-onset central nervous system hemophagocytic lymphohistiocytosis: a case report

Background

Hemophagocytic lymphohistiocytosis (HLH) is a clinical syndrome with both genetic and acquired causes characterized by elevated cytokine levels, hyperinflammation, and overactivation of lymphocytes and macrophages. It is typically a systemic disease with variable degrees of CNS involvement. Cases with predominantly central nervous system (CNS) involvement are very rare, with the vast majority of these occurring in infants and young children. This report documents a case of adult-onset CNS-HLH involving a middle-aged man.

Case presentation

A 55 year-old man developed progressive left hemiparesis and aphasia over the course of several months. Brain MRI showed multifocal, mass-like enhancing lesions with increased susceptibility consistent with blood products. An extensive workup for infectious, autoimmune, and neoplastic etiologies was significant only for a markedly elevated serum ferritin at 1456 ng/mL. Two brain biopsies showed a non-specific inflammatory process. The patient was treated empirically with steroids and plasmapheresis, but he continued to suffer a progressive neurological decline and died one year after onset of neurological symptoms. Autopsy revealed profound histiocytic infiltration, perivascular lymphocytosis, and emperipolesis, compatible with CNS-HLH.

Conclusion

This case report describes an exceedingly rare presentation of an adult patient with CNS predominant HLH. This diagnosis should be considered in the differential diagnosis of adults presenting with progressive brain lesions, even in the absence of typical systemic signs of HLH.

Hemophagocytic lymphohistiocytosis syndrome in Dengue hemorrhagic fever

Hemophagocytic lymphohistiocytosis (HLH) is a life threatening florid activation of macrophages of the lymphoreticular system. It is reported to be associated with dengue in children in India and carries a high mortality. Patients present with high fever, worsening blood cell counts, splenomegaly, abnormal liver enzymes with features of liver failure, coagulopathy and neurological complications. The diagnosis is according to "Diagnostic Guidelines for HLH 2004", based on a triad of clinical, blood parameters and bone marrow cytology. In the present study, data of 212 children admitted with dengue were analyzed. Of 212 children, 31 children were classified as suspect HLH and advised bone marrow evaluation; of whom 23 children had marrow evidence of HLH. Worsening of blood cell counts were recorded in all children with a mean platelet count of 58,303.03 cells/cumm, low hematocrit in 95.65 %, low mean hemoglobin level of 8.37 g/dL, high erythrocyte sedimentation rate (ESR) and prolonged pro-thrombin time/international normalization ratio (PT/INR). Serum triglycerides, ferritin and transaminases were high. Of the 23 children, 19 patients received intravenous immunoglobulin (IVIG) and all of these children recovered. Dengue with multi-organ dysfunction is commonly concurrent to HLH in the marrow and hence, an early diagnosis based on clinical, laboratory and bone marrow evaluation is significant. A bone marrow evaluation confirms the diagnosis of HLH.

A case of acute encephalopathy with hemophagocytic lymphohistiocytosis and clonal T-cell expansion

We report on a 9-year-old boy who presented with acute encephalopathy and hemophagocytic lymphohistiocytosis (HLH). The patient was referred to our hospital because of fever, seizures, and decreased consciousness. He showed moderately elevated levels of proinflammatory cytokines in the cerebrospinal fluid and plasma, and clonal expansion of highly activated CD8⁺ T cells in the peripheral blood. These CD8⁺ T cells were found to be larger cells that stained positive for T-cell receptor Vβ13.6, and decreased shortly after steroid therapy. Our findings suggest that his acute encephalopathy was likely a clinical manifestation of HLH, and that immunophenotypic analysis may be helpful for early recognition of HLH in such rare encephalopathy.

A suggested approach to the etiologic evaluation of status epilepticus in children: what to seek after the usual causes have been ruled out

Status epilepticus represents a true neurologic emergency that requires immediate treatment to stop seizure activity and prompt diagnostic evaluation to recognize potentially treatable causes. Although an etiology may be detected in many cases, in a significant number of patients the cause is not established by the usual laboratory or neuroimaging studies. We performed an extensive literature review of all unusual and often overlooked causes of status epilepticus in children, in an attempt to provide physicians with practical information on the diagnostic approach to patients, particularly those with refractory status epilepticus, for whom an etiology can not be detected by routine diagnostic protocols.

Familial hemophagocytic lymphohistiocytosis: clinical and neuroradiological findings and review of the literature

BACKGROUND

Familial hemophagocytic lymphohistiocytosis (FHL) is a rare multisystem congenital disorder characterized by uncontrolled proliferation and infiltration of activated lymphocytes and histiocytes, secreting high amounts of inflammatory cytokines; this may affect multiple organs including liver, spleen, lymph nodes, bone marrow, and central nervous system (CNS; Janka, Eur J Pediatr 166:95-109, 1).

OBJECTIVE

The objective of this study is to describe the characteristics of the encephalopathy and to correlate the neuroradiological findings with the clinical symptoms and the treatment response in a child with FHL type 3 studied by total body computed tomography and by brain magnetic resonance (MR) and MR spectroscopy.

RESULTS

VF, a 14-month-old female, developed a full-blown FHL, with facial nerve palsy as the only CNS complication. Brain MR imaging showed several focal areas of pathological signal in the subcortical and periventricular white matter, left thalamus, cerebellum, and brain stem. Proton MR spectroscopy also demonstrated no elevated peak of Cho, no lactate peak, and elevated glutamine/glutamate complex. Moreover, an elevated N-acetyl aspartate (NAA) peak was detected. The follow-up MR study after hematopoietic stem cells transplantation showed a dramatic reduction of the lesions and normalization of the metabolic pattern at spectroscopy.

CONCLUSION

Brain lesions and metabolic alterations documented by MR and spectroscopy during active FHL reverted during disease control achieved by therapy.

Central nervous system involvement in Turkish children with primary hemophagocytic lymphohistiocytosis

This report mainly presents the clinical and laboratory findings in a group of 15 primary hemophagocytic lymphohistiocytosis patients with central nervous system involvement (group 1) and compares some of the findings with those of 13 hemophagocytic lymphohistiocytosis patients without central nervous system involvement (group 2). Statistical analysis showed that age and sodium level at diagnosis were significantly higher while alanine aminotransferase and bilirubin levels were significantly lower in group 1 than group 2 (P < .05). There were no statistically significant differences between the 2 groups in the other clinical, laboratory, and overall survival parameters. Three patients in group 1 initially had central nervous system involvement in the absence of systemic findings, which led to the initial misdiagnosis of these patients as central nervous system disorders other than hemophagocytic lymphohistiocytosis.

A spectrum of neuroradiological findings in children with haemophagocytic lymphohistiocytosis

BACKGROUND

Haemophagocytic lymphohistiocytosis (HLH) is a rare multisystem disorder. CNS involvement is a frequent and poor prognostic component. Better neuroradiological surveillance may be beneficial for patient management and outcome.

OBJECTIVE

To describe various neuroradiological findings in nine patients with HLH with an emphasis on correlation with disease activity and treatment response.

MATERIALS AND METHODS

Between 1996 and 2007, nine children with HLH with CNS involvement were identified in a single centre. Neuroradiological findings from CT, MRI, and proton MR spectroscopy, and the clinical records of the nine children were retrospectively reviewed. The frequency, distribution, characteristics of abnormal neuroradiological findings and changes during follow-up were correlated with clinical findings.

RESULTS

Initial abnormal findings included multiple nodular or ring-enhancing parenchymal lesions, a laminated pattern of nodular parenchymal lesions on T2-weighted images, leptomeningeal enhancement, confluent parenchymal lesions, mild ventriculomegaly, and diffuse brain oedema. On follow-up imaging studies, haemorrhagic transformation and atrophy were seen where brain parenchymal lesions had been previously. These abnormal neuroradiological findings showed good correlation with clinical findings. Proton MR spectroscopy also demonstrated typical changes of metabolites during the course of the disease.

CONCLUSION

A spectrum of neuroradiological findings in children with HLH is well matched with the clinical course of the disease and, therefore, a comprehensive analysis of the findings is useful to monitor disease activity and treatment responses.

A neurologic presentation of familial hemophagocytic lymphohistiocytosis which mimicked septic emboli to the brain

Familial hemophagocytic lymphohistiocytosis is an inherited deficiency of natural killer cell function and excessive cytokine activity, which predominantly presents in early childhood. The initial symptoms of familial hemophagocytic lymphohistiocytosis are often nonspecific but may be predominantly neurologic. The case presented here describes an 18-month-old boy who initially presented with fever, encephalopathy, and hemiparesis. He had innumerable brain lesions visualized on magnetic resonance imaging scans. An infectious etiology was excluded, and brain, liver, and bone marrow biopsies were nonspecific but consistent with hemophagocytic lymphohistiocytosis. Cells were sent for flow cytometry perforin analysis, which demonstrated defective natural killer cell function. A diagnosis of familial hemophagocytic lymphohistiocytosis was confirmed by mutation analysis and decreased expression of the perforin gene, in the patient and immediate family members. These results showed the patient to be a compound heterozygote for perforin mutations. His case illustrates the potential for a fulminant neurological presentation of familial hemophagocytic lymphohistiocytosis with widespread lesions in the brain.

Hemophagocytic syndromes

Hemophagocytic syndromes (hemophagocytic lymphohistiocytosis, HLH) represent a severe hyperinflammatory condition with the cardinal symptoms prolonged fever, cytopenias, hepatosplenomegaly, and hemophagocytosis by activated, morphologically benign macrophages. Biochemical markers include elevated ferritin and triglycerides, and low fibrinogen. Whereas in children several inherited immune deficiencies may lead to this syndrome, most adults with HLH have no known underlying immune defect. Nevertheless, impaired function of natural killer (NK) cells and cytotoxic T-cells (CTL) is characteristic for both genetic and acquired forms of HLH. Frequent triggers are infectious agents, mostly viruses of the herpes group. Malignant lymphomas, especially in adults, may be associated with HLH. A special form of HLH in rheumatic diseases is called macrophage-activation syndrome. Initially HLH may masquerade as a normal infection since all symptoms, even though less pronounced, may also be found in immune competent patients. Patients with HLH, however, cannot control the hyperinflammatory response which, if untreated, is fatal in genetic cases and in a high percentage of acquired cases. Awareness of the clinical symptoms and of the diagnostic criteria of HLH is important to start life-saving therapy with immunosuppressive/immunomodulatory agents in time.

CNS involvement in hemophagocytic lymphohistiocytosis: CT and MR findings

Hemophagocytic lymphohistiocytosis (HLH) is a rare disorder that is characterized by proliferation of benign histiocytes, and this commonly involves the liver, spleen, lymph nodes, bone marrow and central nervous system (CNS). We report here on the CT and MR imaging findings in a case of CNS HLH that showed multiple ring enhancing masses mimicking abscess or another mass on the CT and MR imaging.

Familial and acquired hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening condition of severe hyperinflammation caused by the uncontrolled proliferation of activated lymphocytes and histiocytes secreting high amounts of inflammatory cytokines. Cardinal signs and symptoms are prolonged fever, hepatosplenomegaly and pancytopenia. Characteristic biochemical markers include elevated triglycerides, ferritin and low fibrinogen. HLH occurs on the basis of various inherited or acquired immune deficiencies. Impaired function of natural killer (NK) cells and cytotoxic T-cells (CTL) is shared by all forms of HLH. Genetic HLH occurs in familial forms (FHLH) in which HLH is the primary and only manifestation, and in association with the immune deficiencies Chédiak-Higashi syndrome 1 (CHS 1), Griscelli syndrome 2 (GS 2) and x-linked lymphoproliferative syndrome (XLP), in which HLH is a sporadic event. Most patients with acquired HLH have no known underlying immune deficiency. Both acquired and genetic forms are triggered by infections, mostly viral, or other stimuli. HLH also occurs as a complication of rheumatic diseases (macrophage activation syndrome) and of malignancies. Several genetic defects causing FHLH have recently been discovered and have elucidated the pathophysiology of HLH. The immediate aim of therapy in genetic and acquired HLH is suppression of the severe hyperinflammation, which can be achieved with immunosuppressive/immunomodulatary agents and cytostatic drugs. Patients with genetic forms have to undergo stem cell transplantation to exchange the defective immune system with normally functioning immune effector cells. In conclusion, awareness of the clinical symptoms and of the diagnostic criteria of HLH is crucial in order not to overlook HLH and to start life-saving therapy in time.

Primary necrotizing lymphocytic central nervous system vasculitis due to perforin deficiency in a four-year-old girl

We report the case of a 4-year-old girl who presented with headaches, ataxia, and visual disturbances. Cranial magnetic resonance imaging showed multiple supra- and infratentorial lesions with peripheral contrast enhancement and central necrosis. Brain biopsy revealed necrotizing lymphocytic vasculitis of undetermined etiology. Perforin expression was found to be significantly reduced in the patient's peripheral blood cells, and sequence analysis of the patient's perforin gene showed a compound heterozygous state with 1 nonsense mutation and 2 missense alterations in exon 2. Central nervous system (CNS) vasculitis was thus attributed to the perforin deficiency, and the patient was successfully treated by transplantation of stem cells from an HLA-identical brother. The findings described herein indicate that, even in the absence of classic non-neurologic symptoms of hemophagocytic lymphohistiocytosis, measurement of perforin expression should be one of the diagnostic tests used to identify the cause of unexplained CNS vasculitis, since this may have profound implications regarding therapy.

Familial and acquired hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening condition characterized by uncontrolled hyperinflammation on the basis of various inherited or acquired immune deficiencies. Cardinal symptoms are prolonged fever, hepatosplenomegaly and cytopenias. Central nervous system (CNS) symptoms are common. Biochemical markers include elevated triglyceride and ferritin, high levels of the alpha chain of the soluble interleukin-2 receptor and low fibrinogen. Impaired function of natural killer (NK) cells and cytotoxic T-cells (CTL) is a characteristic of all forms of HLH. Genetic HLH occurs in familial forms (FHLH), in which HLH is the primary and only manifestation, and in association with the immune deficiencies Chédiak-Higashi syndrome (CHS), Griscelli syndrome (GS) and X-linked lymphoproliferative syndrome (XLP), in which secondary HLH occurs sporadically. Most patients with acquired HLH have no known underlying immune deficiency. Both acquired and genetic forms are triggered by infections, mostly viruses, or other stimuli. HLH also occurs as a complication of rheumatic diseases (macrophage activation syndrome) and of malignancies. The recent discovery of several genetic defects causing FHLH as well as the identification of the genes responsible for CHS, GS and XLP have underscored the role of granule (perforin/granzymes)-mediated cytotoxicity in both the killing of infected cells and the termination of the immune response. The immediate aim of therapy is suppression of the increased inflammatory response by immunosuppressive/immunomodulatory agents and cytotoxic drugs. Genetic cases can only be cured with stem cell transplantation. Awareness of the clinical symptoms and of diagnostic criteria for HLH is crucial to starting life-saving therapy in time.

Hemophagocytic lymphohistiocytosis masquerading as child abuse: presentation of three cases and review of central nervous system findings in hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a rare disease resulting from abnormal proliferation of histiocytes in tissues and organs. Although the disease generally presents with systemic symptoms such as pancytopenia, coagulopathy, and organomegaly, HLH may also present with central nervous system (CNS) manifestations. CNS events can range from irritability to encephalopathy and coma. Retinal and intracranial hemorrhages are among the neuropathologic findings in these children. Patients who present with CNS findings may have symptoms that mimic those of inflicted injury. These children are at risk, therefore, for misdiagnosis as victims of child abuse. Such an error causes not only unnecessary additional trauma to the family but also, more important, a delay in initiating effective therapy. We present 3 cases of children with HLH who initially came to medical attention with neurologic findings, all suspected to be victims of child abuse. Subsequent laboratory evaluations, however, were consistent with the diagnosis of HLH. No additional evidence of child abuse was obtained, and the charges eventually were dropped. Two of the 3 children died from their disease shortly after presentation; the third is surviving with no evidence of HLH several months after allogeneic bone marrow transplantation. Although the diagnosis of child abuse certainly is all too common, clinicians need to be diligent and informed to avoid assigning this label erroneously. Several laboratory findings of HLH may alert physicians to the possibility of this diagnosis. The timely diagnosis of and institution of therapy for HLH may reduce ultimate morbidity and mortality.

Imaging characteristics of hemophagocytic lymphohistiocytosis

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) is a nonmalignant disorder of immune regulation, with overproduction of cytokines and diminished immune surveillance. Symptoms are nonspecific and may affect multiple organs, including the central nervous system. Neuroimaging findings have been described in case reports and small series; body imaging findings have not been described extensively. OBJECTIVE. To summarize findings of the most frequently performed imaging studies of the brain, chest and abdomen in patients with HLH.

MATERIALS AND METHODS

Retrospective review of chest radiographs and CT, abdominal ultrasound and CT, brain CT and MRI, skeletal surveys, and autopsy data.

RESULTS

Twenty-five patients were diagnosed and treated for HLH at our institution over an 11-year period; 15 patients (60%) died. Common chest radiograph findings included alveolar-interstitial opacities with pleural effusions, often with rapid evolution and resolution. Hepatosplenomegaly, gallbladder wall thickening, hyperechoic kidneys and ascites were common abdominal findings, which resolved after therapy in some cases. Brain-imaging studies revealed nonspecific periventricular white-matter abnormalities, brain-volume loss and enlargement of extra-axial fluid spaces. Three infant cases, one with intracranial hemorrhage, one with multiple pathologic rib fractures and one with diaphyseal periosteal reaction involving multiple long bones on skeletal survey, raised suspicion of child abuse at presentation. Abuse was not substantiated in any case.

CONCLUSIONS

Clinicians and radiologists should be aware of the radiographic manifestations of HLH, which are nonspecific and overlap with infectious, inflammatory and neoplastic disorders. Findings in the chest (similar to acute respiratory distress syndrome) and abdomen may progress rapidly and then regress with institution of appropriate anti-HLH therapy. CNS findings may be progressive. In some infants, initial imaging findings may mimic nonaccidental trauma.