Clinical, serologic and magnetic resonance imaging of 3 cases of inflammatory myopathy with abundant macrophages in the Japanese population

Rare forms of inflammatory myopathies - part I, generalized forms

INTRODUCTION

The idiopathic inflammatory myopathies traditionally comprise dermatomyositis, polymyositis, immune-mediated necrotizing myopathy, anti-synthetase syndrome, and inclusion body myositis. In this review, we aimed to cover the less common forms of generalized myositis.

AREAS COVERED

We identified rare forms of widespread myositis on the basis of list provided by the homepage of the Neuromuscular disease center of Washington University, USA and on the basis of the authors' knowledge. We searched PubMed® and EMBASE® for relevant articles on these forms with the aim of providing as much as possible information on their clinical manifestations as well as guidance on their work-up and treatment.

EXPERT OPINION

There is substantial heterogeneity among the various rare forms of generalized myositis in terms of their frequency and characterization. Some forms are reasonably well defined, while others may not represent truly well-defined diseases, but rather variants of other myopathies. The landscape of rare forms appears to have evolved over time, with some forms now being better characterized, while others, such as SARS-Cov-2- and immune checkpoint inhibitor-related myositis have come to the fore only in recent years. Knowledge about rare forms of myositis can aid in their recognition and treatment.

Treatment and Mortality of Hemophagocytic Lymphohistiocytosis in Adult Critically Ill Patients: A Systematic Review With Pooled Analysis

OBJECTIVES

Hemophagocytic lymphohistiocytosis is a cytokine release syndrome caused by uncontrolled immune activation resulting in multiple organ failure and death. In this systematic review, we aimed to analyze triggers, various treatment modalities, and mortality in critically ill adult hemophagocytic lymphohistiocytosis patients.

DATA SOURCES

MEDLINE database (PubMed) at October 20, 2019.

STUDY SELECTION

Studies and case series of patients greater than or equal to 18 years old, of whom at least one had to be diagnosed with hemophagocytic lymphohistiocytosis and admitted to an ICU.

DATA EXTRACTION

Source data of studies and case series were summarized and analyzed on an individual basis. Multivariable logistic regression analysis was performed adjusting for age, sex, and trigger groups. Each single treatment agent was entered as a dichotomous variable to determine treatments associated with survival, regardless if given alone or in combination.

DATA SYNTHESIS

In total, 661 patients from 65 studies and case series were included. Overall mortality was 57.8%. Infections were the most frequent trigger (49.9%), followed by malignancies (28.0%), autoimmune diseases (12.1%), unknown triggers (9.4%), and drugs (0.6%). Treatment with IV immunoglobulins was associated with improved survival (odds ratio, 0.548; 95% CI, 0.337-0.891; p = 0.015), while treatment with cyclosporine was associated with increased risk of death (odds ratio, 7.571; 95% CI, 3.702-15.483; p < 0.001). Considering different trigger groups separately, same results occurred only for infection-triggered hemophagocytic lymphohistiocytosis. No information was available on disease severity and other confounding factors.

CONCLUSIONS

Mortality of hemophagocytic lymphohistiocytosis in the ICU is high. Most common triggers were infections. Results of survival analyses may be biased by treatment indication and disease severity. Future studies prospectively investigating treatment tailored to critically ill hemophagocytic lymphohistiocytosis patients are highly warranted.

Hemophagocytic syndrome and inflammatory myopathy with abundant macrophages in a patient with adult-onset Still's disease

We herein describe a 71-year-old woman with adult-onset Still's disease (AOSD) who developed fever, myalgia, and pancytopenia. The bone marrow aspiration and muscle biopsy revealed hemophagocytic syndrome (HPS) and inflammatory myopathy with abundant macrophages (IMAM). Immunostained specimens were positive for expression of retinoic acid-inducible gene-I (RIG-I), which recognizes viral RNA in infiltrated mononuclear cells as well as muscle tissues. These findings suggest that RIG-I may be involved in induction of HPS and IMAM in AOSD.

Protracted febrile myalgia syndrome in a Japanese patient with fasciitis detected on MRI

Protracted febrile myalgia syndrome (PFMS) is a rare manifestation of familial Mediterranean fever characterized by prolonged severe myalgia. We herein describe a case of PFMS with fasciitis on magnetic resonance imaging. The response to corticosteroid therapy was prompt, as is typical for PFMS. An MEFV gene analysis revealed the patient to be homozygous for E148Q and compound heterozygous for P369S-R408Q. This is the first case report of a Japanese patient with PFMS. MRI findings may help to diagnose such cases.