ICD-11 classes
08 Diseases of the nervous system
Diseases of neuromuscular junction or muscle
Primary disorders of muscles
4A41 — Idiopathic inflammatory myopathy
4A41.1 — Polymyositis
4A41.10 — Juvenile polymyositis
ICD-11 4A41.10 — Juvenile polymyositis
Juvenile polymyositis is a rare childhood idiopathic inflammatory myopathy. It is frequently misdiagnosed, as it lacks a unique clinical phenotype. Traditionally, it presents with weakness of the proximal muscles that evolves over weeks to months. The primary histologic features in are fibre size variability, scattered necrotic and regenerating fibres, and perivascular and endomysial cellular infiltrates.
The diagnosis includes nothing.
It excludes 5 items.
- Systemic sclerosis (4A42)
- Overlap or undifferentiated nonorgan specific systemic autoimmune disease (4A43)
- Antiphospholipid syndrome (4A45)
- Vasculitis (4A44)
- Lupus erythematosus (4A40)
It has no clarifying diagnoses.
The diagnosis is coded elsewhere:
- Polymyositis #3636
- Polymyositis #10078
- Polymyositis #18364