Actuality of juvenile dermatomyositis

Juvenile dermatomyositis in Thai children: Retrospective review of 30 cases from a tertiary care center

BACKGROUND

Juvenile dermatomyositis is a rare condition, but it is the most common idiopathic inflammatory myopathy in pediatric patients.

AIM

To study the clinical manifestations, investigations, treatment, clinical course, and outcomes of juvenile dermatomyositis in Thai children.

METHOD

This retrospective study included juvenile dermatomyositis patients treated at Siriraj Hospital, a 2,300-bed national tertiary referral center in Bangkok, Thailand, from 1994 to 2019.

RESULTS

Thirty patients (22 females and 8 males) were included with a female to male ratio of 2.7:1. Median age at diagnosis was 5.1 years (range, 2.6-14.8 years). Median duration of illness before diagnosis was 6.5 months (range, 0.3-84.0 months). Acute and subacute onset occurred in the majority of patients. Presenting symptoms included muscle weakness in 27/30 (90%), skin rash in 26/30 (86.7%), muscle pain in 17/26 (65.4%), and arthralgia in 4/18 (22.2%) of patients. Dermatologic examination revealed Gottron's rash, heliotrope rash, and periungual telangiectasia in 25/30 (83.3%), 21/30 (70.0%), and 15/24 (62.5%) of patients, respectively. Interestingly, scalp dermatitis was found in 8/21 (38.1%) of patients. The most commonly used treatment regimen in this series was a combination of prednisolone and methotrexate. During the median follow-up of 3.1 years (range, 0.0-18.5 years), only one-third of patients were seen to have monocyclic disease. Extraskeletal osteosarcoma at a previous lesion of calcinosis cutis was observed in one patient at 12 years after juvenile dermatomyositis onset.

LIMITATIONS

This was a retrospective single-center study, and our results may not be generalizable to other healthcare settings. Prospective multicenter studies are needed to confirm the findings of this study.

CONCLUSION

juvenile dermatomyositis usually poses a diagnostic and therapeutic challenge, which can be compounded by the ethnic variations in the clinical presentation, as observed in this study. Asian patients tend to present with acute or subacute onset of disease, and arthralgia and/or arthritis are less common than in Caucasian patients. Scalp dermatitis is not uncommon in pediatric juvenile dermatomyositis patients. An association between juvenile dermatomyositis and malignancy, though rare, can occur.

The family impact of caring for a child with juvenile dermatomyositis

Background Juvenile dermatomyositis (JDM), a rare autoimmune disease, accounts for more than 80% of idiopathic inflammatory myopathy childhood cases, making it the most common idiopathic inflammatory myopathy among children. The average age of onset is approximately 7 years and commonly leads a chronic course. Symptoms of JDM include cutaneous features (Gottron's rash, heliotrope rash, or nail fold capillary changes), musculoskeletal features, calcinosis and lipodystrophy (a symmetrical deficit of subcutaneous fatty tissue), and acanthosis (thickening of the skin). Despite improvement in treatment regimens and the lowering of mortality rates, some children still lose their lives to JDM. This study assessed the effects of caring for a child diagnosed with JDM on the family system. Methods Participants included 36 mothers and 3 fathers of a child diagnosed with JDM. Parents were administered self-report measures, which assessed the overall family functioning (PedsQL-Family Impact Module), and the parents' mood and level of distress (profile of mood states). Additionally, parents were administered a semi-structured interview that included background information, psychosocial information, and sources of support. Results and conclusion Families of children with JDM reported difficulties in family functioning, communication problems, and an increased number of conflicts. Parents appeared to be experiencing higher than average levels of worry, worse physical functioning, and family relationships when compared to normative populations. Parents would benefit from psychosocial support due to the many challenges associated with caring for a child with JDM.

Imaging findings in systemic childhood diseases presenting with dermatologic manifestations

PURPOSE

Many childhood diseases often present with skin abnormalities with which radiologists are largely unfamiliar. Knowledge of associated dermatologic manifestations may aid the radiologist in confirming the diagnosis and recommending targeted imaging of affected organs.

METHODS

We review the imaging findings in childhood diseases associated with dermatologic manifestations.

FINDINGS

Diseases include dermatologic findings which herald underlying malignancy (Neuroblastoma, leukemia/lymphoma, Langerhans cell histiocytosis),are associated with risk of malignancy (Epidermolysis Bullosa, basal cell nevus syndrome, Cowden's syndrome, Tuberous Sclerosis),or indicate a systemic inflammatory/immune disorder (Kawasaki's disease, Henoch Schonlein Purpura, systemic lupus erythematosus, scleroderma, sarcoidosis, dermatomyositis and immune thrombocytopenic purpura).

CONCLUSION

Familiarity with pertinent findings in childhood diseases presenting with dermatologic manifestations in childhood diseases aids the radiologist in confirming the diagnosis and guiding imaging workup.

[Juvenile dermatomyositis: Early onset and unusual presentation]

Juvenile dermatomyositis (JDM) is a rare disease, with a mean age of onset of 7 years. We report a case of JDM in a 13-month-old infant.

OBSERVATION

A 13-month-old infant presented with an edema of the upper lip, 4 days after receiving amoxicillin-clavulanate. The patient was treated with betamethasone and an antihistamine. Progression was marked by the appearance of a white edema of the periorbital area and the upper lip, with purpuric lesions, aphthoid ulcerations, and a drooping head. Very high muscle enzymes, a myogenic electromyogram, and hypertrophic cardiomyopathy were found and diagnosis of JDM was retained. The patient was treated with a high dose of corticosteroids and methotrexate. Before the installation of dysphagia, dysphonia, and axial hypotonia, the bolus of cyclophosphamide was administered, with clear improvement. Corticosteroids and methotrexate were then kept over the long term.

DISCUSSION AND CONCLUSION

The originality of this observation of JDM resides in the very young age of onset of the disease, its unusual cutaneous signs including labial edema extending to the regions around the eyes, its severe muscle manifestations causing axial hypotonia, and finally, in its association with hypertrophic cardiomyopathy. Early initiation of treatment (12 days after the onset of symptoms) greatly improved the prognosis of this form of JDM, which is very severe and refractory to first-line therapy.

Differential roles of hypoxia and innate immunity in juvenile and adult dermatomyositis

Dermatomyositis (DM) can occur in both adults and juveniles with considerable clinical differences. The links between immune-mediated mechanisms and vasculopathy with respect to development of perifascicular pathology are incompletely understood. We investigated skeletal muscle from newly diagnosed, treatment-naïve juvenile (jDM) and adult dermatomyositis (aDM) patients focusing on hypoxia-related pathomechanisms, vessel pathology, and immune mechanisms especially in the perifascicular region. Therefore, we assessed the skeletal muscle biopsies from 21 aDM, and 15 jDM patients by immunohistochemistry and electron microscopy. Transcriptional analyses of genes involved in hypoxia, as well as in innate and adaptive immunity were performed by quantitative Polymerase chain reaction (qPCR) of whole tissue cross sections including perifascicular muscle fibers.Through these analysis, we found that basic features of DM, like perifascicular atrophy and inflammatory infiltrates, were present at similar levels in jDM and aDM patients. However, jDM was characterized by predominantly hypoxia-driven pathology in perifascicular small fibers and by macrophages expressing markers of hypoxia. A more pronounced regional loss of capillaries, but no relevant activation of type-1 Interferon (IFN)-associated pathways was noted. Conversely, in aDM, IFN-related genes were expressed at significantly elevated levels, and Interferon-stimulated gene (ISG)15 was strongly positive in small perifascicular fibers whereas hypoxia-related mechanisms did not play a significant role.In our study we could provide new molecular data suggesting a conspicuous pathophysiological 'dichotomy' between jDM and aDM: In jDM, perifascicular atrophy is tightly linked to hypoxia-related pathology, and poorly to innate immunity. In aDM, perifascicular atrophy is prominently associated with molecules driving innate immunity, while hypoxia-related mechanisms seem to be less relevant.

A fatal presentation of dermatomyositis with facial swelling

Juvenile dermatomyositis (JDM) is the most common inflammatory autoimmune myopathy in children. Most common presentations consist of heliotrophic rash and/or gottron's papules in addition to proximal muscle weakness. A typical presentations have been reported. We present a 13-year-old African American male who presented with a two-week history of bilateral periorbital edema that was unresponsive to glucocorticoids. He had elevated transaminases but no detectable muscle weakness. A muscle biopsy was consistent with juvenile dermatomyositis. This case highlights the need to consider dermatomyositis in cases of facial swelling and the use of aggressive immunosuppressive therapies due to its associated vasculopathies.