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Muscle pathology in juvenile dermatomyositis
E E Calore1, M J Cavaliere, N M Perez
1Instituto de Infectologia Emílio Ribas, Seção de Anatomia Patológica, São Paulo, Brasil.
Insights
Muscle biopsy is a valuable tool for diagnosing infantile dermatomyositis and identifying disease recurrence, even when clinical signs are absent. Histochemistry reveals muscle damage and regeneration patterns, aiding treatment assessment.
Area of Science:
- Pediatric Rheumatology
- Neuromuscular Pathology
Background:
- Infantile dermatomyositis is an idiopathic inflammatory myopathy affecting children.
- Accurate diagnosis and monitoring of disease activity are crucial for effective management.
Purpose of the Study:
- To evaluate the utility of muscle biopsy with histochemistry in diagnosing infantile dermatomyositis.
- To assess the role of muscle biopsy in detecting disease recurrences.
Main Methods:
- Ten children with clinical features of inflammatory myopathy underwent vastus lateralis muscle biopsy.
- Histochemical analysis was performed on all muscle biopsy samples.
Main Results:
- Muscle fiber architectural changes, necrosis, and regeneration were observed, particularly in untreated patients or those with persistent weakness.
- Minimal changes were noted in patients treated for over a year.
- Muscle necrosis and architectural alterations were detected in three cases with clinical and laboratory recurrences.
Conclusions:
- Muscle biopsy and histochemistry are effective in diagnosing infantile dermatomyositis.
- This method aids in detecting disease recurrences, even in subclinical cases.
Objective:
To study muscle biopsies, using histochemistry, on ten children with infantile dermatomyositis.
Design:
Series of ten patients (of whom eight patients had received treatment and two had not) were submitted to muscle biopsy in order to diagnose possible inflammatory myopathy or to detect recurrences. PLACE OF DEVELOPMENT OF THE STUDY: Public Health Service of São Paulo State.
Participants:
Children with clinical features of inflammatory myopathy.
Intervention:
Biopsies were performed on the vastus lateralis using local anesthetic. Histochemistry was performed according to standardized methods.
Results:
Architectural changes of the muscle fibers, necrosis of variable intensity and accentuated evidence of regeneration were observed in patients who had not received treatment (2 cases) and in one case where muscular weakness persisted in spite of corticosteroid therapy. Necrosis and regeneration were minimal or absent in cases treated for one year or more (4 cases). In 3 cases with clinical and laboratorial recurrences, muscle necrosis and architectural changes were detected.
Conclusions:
It was concluded that muscle biopsy could aid in diagnosing infantile dermatomyositis as well as in detecting recurrences even in cases without clinical activity of the disease.