Syndrome d’activation macrophagique d’origine infectieuse : étiologies et prise en charge

Spectrum of neuroradiological manifestations in primary hemophagocytic lymphohistiocytosis: a comparative study of EBV-induced versus non-EBV-induced forms in 75 genetically confirmed pediatric cases

OBJECTIVES

Hemophagocytic lymphohistiocytosis (HLH) is a rare and life-threatening condition affecting young children. It is potentially triggered by Epstein-Barr virus (EBV). This study describes the neuroradiological features observed in 75 children with genetically confirmed primary HLH, comparing EBV-induced with non-EBV-induced HLH forms.

METHODS

Brain MRIs between 2007 and 2021 from 75 children with HLH according to the 2004 Histiocyte Society criteria and with a confirmed HLH-related mutation, were retrospectively reviewed by two pediatric neuroradiologists blinded to EBV status and to mutation status. At diagnosis, 17 children with EBV viremia above a threshold of 1000 copies/mL were included in the EBV-induced HLH group. The remaining 58 patients were included in the non-EBV-induced HLH group.

RESULTS

Of the 75 children initially included, 21 had abnormal MRI (21/75 (28%); 9/17 in the EBV-induced HLH group and 12/58 in the non-EBV-induced HLH group). All patients with abnormal MRI had neurological symptoms. Abnormal MRIs showed white matter lesions; the posterior fossa was affected in all but one case. There was no significant difference between groups regarding the localization or morphology of white matter lesions. The striatum was more frequently affected in the EBV-induced HLH group (8/9 (89%) versus 1/12 (8%), p = 0.00037). All lesions, whether in the white matter or in the basal ganglia, presented increased ADC values on diffusion weighted imaging (DWI).

CONCLUSION

In this study of 75 children with genetically confirmed HLH, only children with neurological signs had abnormal brain MRI. Bilateral striatum involvement suggested an EBV-induced form of HLH.

KEY POINTS

• In children with genetically proven HLH, only those with neurological signs did have brain abnormalities at MRI. • All patients with abnormal brain MRI had multiple white matter lesions with increased ADC values, including in the posterior fossa in almost all cases. • Basal ganglia and in particular the striatum were bilaterally and symmetrically affected in almost all EBV-induced HLH patients, in contrast to the non-EBV-induced HLH patients.

The Challenging Aspect of Macrophage Activation Syndrome in the Setting of Sepsis or Systemic Inflammatory Response Syndrome (SIRS)

Macrophage activation syndrome (MAS) is a rare but potentially fatal disease. It is characterized by hyperinflammation, including the proliferation and activation of immune cells (CD8 T cells and NK cells) associated with hypercytokinemia. Patients present with fever, splenomegaly, and cytopenia, associated with a hemophagocytosis picture in the bone marrow. It can progress to a multiorgan failure syndrome (MODS), mimicking sepsis or a systemic inflammatory response syndrome (SIRS). We report the case of an 8-year-old girl admitted to the pediatric intensive care unit for the management of major trauma due to a domestic accident. She presented with a protracted fever in the context of a septic shock, despite appropriate treatment. The association with bicytopenia, hyperferritinemia, hypofibrinogenemia, and hypertriglyceridemia was suggestive of MAS which was confirmed by a bone marrow puncture showing hemophagocytosis. A Bolus of corticotherapy was then added to the supportive treatment and broad-spectrum antibiotherapy, with a good outcome.

[Haemophagocytic syndrome secondary to Mediterranean spotted fever]

INTRODUCTION

Haemophagocytic syndrome (HS) is a rare disease with a severe prognosis that is defined by clinical, laboratory and histopathological criteria. Infections represent the classical cause of HS. HS secondary to Mediterranean spotted fever (MSF) is rare with only a few cases being reported in the literature.

OBSERVATIONS

We report two cases of HS secondary to MSF in 2 men aged 77 and 63 years presenting a febrile maculo-purpuric eruption with inoculation ulcer associated with laboratory abnormalities (cytopenia, elevated ferritin, hypertriglyceridaemia). Haemophagocytosis was present in 2 cases. Serology and PCR for Rickettsia conorii were positive and militated in favour of recent infection responsible for the diagnosis of MSF.

DISCUSSION

The first case of HS was described in 1979. Sixteen cases of HS secondary to MSF are described in the literature. Cytopenia associated with hyperferritinaemia and hypertriglyceridaemia strongly suggests MSF complicated by HS. The prognosis depends on the time elapsed since diagnosis and host-specific factors. Immunosuppressants and antibiotics may be necessary to ensure healing.

CONCLUSION

Rickettsioses can induce HS, and this potential complication with a severe prognosis must be known.

Hemophagocytic syndrome in pregnancy: case report, diagnosis, treatment, and prognosis

Diagnosis of hemophagocytic syndrome remains a challenge in particular during pregnancy. Concomitant presence of clinical and biological signs, for example, fever, pancytopenia, hyperferritinemia, and hypertriglyceridemia, should alert clinicians to suspect HPS and proceed to prompt treatments.

The Use of Ferritin to Identify Critically Ill Patients With Secondary Hemophagocytic Lymphohistiocytosis

OBJECTIVES

Thrombocytopenia is a common, multifactorial, finding in ICU. Hemophagocytosis is one of the main explanatory mechanisms, possibly integrated into hemophagocytic lymphohistiocytosis syndrome, of infectious origin in the majority of cases in ICU. The hemophagocytic lymphohistiocytosis is probably underdiagnosed in the ICU, although it is associated with dramatic outcomes. The main objectives of this work were to identify the frequency of secondary hemophagocytic lymphohistiocytosis, and the main prognostic factors for mortality.

DESIGN/SETTING

We conducted a retrospective observational study in all adult patients admitted with suspected or diagnosed hemophagocytic lymphohistiocytosis, between January 1, 2000, and August 22, 2012.

PATIENTS

A total of 106 patients (42%) had significant hemophagocytosis on bone marrow examination, performed for exploration of thrombocytopenia, bicytopenia, or pancytopenia.

MEASUREMENTS AND MAIN RESULTS

The median age was 56 (45-68) and the median Simplified Acute Physiology Score 2 was 55 (38-68). The main reason for ICU admission was hemodynamic instability (58%), predominantly related to sepsis (45% cases). The main precipitating factor found was a bacterial infection in 81 of 106 patients (76%), including 32 (30%) with Escherichia coli infection. Forty six of 106 patients (43%) died in the ICU. They were significantly older, had higher Simplified Acute Physiology Score 2, plasma lactate deshydrogenase bilirubin, and serum ferritin. The fibrinogen and the percentage of megakaryocytes were significantly lower in nonsurvivors when compared with survivors. In multivariate analysis, only serum ferritin significantly predicted death related to hemophagocytosis. A serum ferritin greater than 2,000 μg/L predicted death with a sensitivity of 71% and a specificity of 76%. A decreased percentage of megakaryocytes also predicted patient death in the ICU.

CONCLUSIONS

Hemophagocytosis is common in thrombocytopenic patients with sepsis, frequently included in a postinfectious hemophagocytic lymphohistiocytosis setting. Our study reveals that ferritin could be a reliable prognostic marker in these patients, and hold particular interest in discussing a specific treatment for hemophagocytic lymphohistiocytosis.

[Systemic EBV+ T-cell lymphoproliferative disease of childhood]

Systemic EBV+ T-cell lymphoproliferative disease of childhood is a recent entity described in the 2008 World Health Organisation tumours of haematopoietic system and lymphoid tissues as a clonal T-cell EBV+ systemic proliferation. It occurs after acute or chronic active EBV infection. We report the case of a caucasian, immunocompetent 12-year-old girl, with no particular history, who presented with hemophagocytic lymphohistiocytosis in the aftermath of an infectious mononucleosis. Main symptoms were multiple organ failure, hepatosplenomegaly and pancytopenia. Histopathology of peripheral lymph node and bone marrow revealed a T-cell, CD8+, EBV+ lymphoproliferation. An elevated viral load was detected in blood by PCR. The patient died within 3 weeks. Since most of the cases have been reported in Asia and South America, few cases still have been described in Europe. Unlike B-cell lymphoproliferation in immunocompromised individuals, T-cell EBV+ lymphoproliferation occurs in immunocompetent patients and seems to be the consequence of a proliferative disorder of EBV-infected T-cells, attributed to a cytotoxic T-cell response deficiency. These T-cell proliferations are more frequently immunoreactive for CD8 than CD4. A key feature of the diagnosis might be EBV viral load.

Mechanisms and etiologies of thrombocytopenia in the intensive care unit: impact of extensive investigations

BACKGROUND

Thrombocytopenia is common in the intensive care unit. Potential mechanisms and etiologies behind this phenomenon are multiple and often entangled. We assessed the effect of a systematic approach, using routinely available tests, on the proportion of patients in whom the mechanism (primary objective) and etiology (secondary objective) of thrombocytopenia in a mixed intensive care unit (ICU) could be identified.

METHODS

Before-and-after study of all patients with thrombocytopenia was used. 'Before' group had no intervention. New standard operating procedures for thrombocytopenia management were introduced. In the 'After' group, bone marrow aspiration; determination of fibrinogen dosage, prothrombin time, factor V, D-dimers; assay of fibrin monomers, ferritin, triglycerides, lactic acid dehydrogenase, aspartate transaminase, alanine aminotransferase, vitamin B12, folates, reticulocytes, haptoglobin, and bilirubin were performed.

RESULTS

In the Before group (n = 20), the mechanism (central, peripheral, or mixed) was identified in 10 % versus 83% in After group (n = 23) (p < 0.001) (48% peripheral, 35% mixed). Before intervention, ≥1 etiology was identified in 15% versus 95.7% in the After group (p < 0.001).

CONCLUSIONS

Systematic and extensive investigation using routine tests highlights the mechanisms and etiology of thrombocytopenia in most cases.

[Hemophagocytic syndrome due to Herpes simplex virus after hysteroscopy]

Hemophagocytic syndrome is an uncommon but life-threatening complication of Herpes simplex virus type 1 or 2 infection. Diagnosis is difficult to establish given the low specificity of clinical and biological signs.

[Leprosy with an unusual course]

In developed countries, Hansen disease, or leprosy, is a rare and little-known disease. Over the last few years, its prevalence in New Caledonia has remained stable (0.35 per 10,000 inhabitants). We report the case of an 11-year-old child who presented lepromatous leprosy complicated by a type 2 reaction. Despite appropriate treatment, the course was unusual with fever lasting a few weeks associated with asthenia, weight loss, and biological perturbations such as inflammatory syndrome, anemia, and hyperferritinemia. After a brief review of Hansen disease and its complications, we discuss the different hypotheses that can explain the clinical and biological progression of our patient (hemolytic anemia secondary to dapsone, type 2 reaction, and aspects of hemophagocytic syndrome) and describe therapeutic management, which led to a good outcome.

[Pancytopenia in disseminated tuberculosis: Think of macrophage activation syndrome]

INTRODUCTION

The macrophage activation syndrome (MAS), also known as haemophagacytosis, is a non-specific clinical syndrome, which includes, among other things general debility, fever and hepatospleneomegaly. The most frequent pathological abnormalities are pancytopenia, hypertryglyceraemia, and hyperferrititinaemia. These clinical and biological criteria, which determine the severity of MAS, must be associated with a histological criterion - haemophagocytosis (with histiocytosis), which is usually medullary but can more rarely be splenic, hepatic or ganglionic. MAS can be primary or secondary. In the latter case, it is frequently associated with an infection of which tuberculosis is the most common.

OBSERVATION

We describe the case of a young immunocompetent patient who had disseminated tuberculosis complicated by MAS.

CONCLUSION

It is important to be aware of MAS, because its occurrence is associated with a poor prognosis and its optimal treatment, which requires a multidisciplinary approach, has not been fully defined. The optimum strategy in relation to specific aetiologies remains to be clarified.