This document provides an overview of polymyositis and dermatomyositis. Polymyositis is an idiopathic inflammatory myopathy that causes symmetrical proximal muscle weakness. It is caused by defective cellular immunity and can be associated with viral infections, malignancies or drugs. Symptoms include proximal muscle weakness in the upper and lower limbs and may include extra skeletal symptoms. Investigations include blood tests, EMG and muscle biopsy. Treatment involves corticosteroids and immunosuppressive agents. Dermatomyositis is a similar condition with additional characteristic skin manifestations. Both conditions are treated with corticosteroids, immunosuppressants and addressing any skin symptoms.
4. DEFINITION
Polymyositis is an idiopathic inflamatory myopathy
that causes symmetrical proximal muscle weakness,
elevated skeletal muscle enzyme levels,characteristic
electromyograhic pattern and muscle biopsy findings.
5. ETIOLOGY
Polymyositis is an immune-mediated syndrome secondary
to defective cellular immunity that is most commonly
associated with other systemic autoimmune diseases. It
may be due to diverse causes that occur alone or in
association with
Viral infections
Malignancies
Drugs
8. SYMPTOMS
Proximal muscle weakness of both upper
and lower limbs causes
Difficulty in raising arms,lifting objects
and combing hairs
Difficulty in climbing and descending
stairs,sitting on curb and raising from
sitting posture
16. PATHOGENSIS
Dermatomyositis is considered to be the result of a humoral attack
against the muscle capillaries and small arterioles (endothelium of
the endomysial blood vessels).
17. SYMPTOMS
Proximal Muscle Weakness
Skin Manifestations
Systemic Systems
SIGNS
Heliotrope Rash
Gottron Papules
Dilated capillary loops at base of finger nails
20. TREATEMENT OF SKIN DISEASES
FIRST lINE THERAPY
Sun avoidance
Sun protection measures
Hydroxychloroquine/chloroquine
Methotrexate is fist line therapy if anti malarial are
contraindicated
Consultation