Symmetric weakness
Proximal greater than distal weakness
Deltoid and hip flexors
difficulty standing from a chair
Onset over months
Mild myalgias
Dysphagia due to esophageal muscle dysfunction
GERD due to smooth muscle inflammation, gastric ulcer disease
Thoracic muscle weakness
Deltoid and hip flexors
difficulty standing from a chair
Heliotrope rash on face scalp
Periorbital edema
Gottron's papules (rash on MCP, PIP, and DIP joints)
Shawl sign (rash above shoulders)
Pruritus
Calcinosis
Nodules over joints can lead to debilitating contractures, especially in children
Nodules over joints can lead to debilitating contractures, especially in children
Respiratory manifestations associated with presence of anti-Jo1 antibody
Increased risk of aspiration, which is a leading cause of death in patients with restricted mobility
Poor prognosis
Interstitial lung disease
Thoracic muscle weakness
Increased risk of aspiration, which is a leading cause of death in patients with restricted mobility
Dilated cardiomyopathy
Cardiac myositis
Suspect in known<unk>  with mild rhythm disturbances, CHF or myocardial fibrosis
Causes include reentry pathways, fibrosis, altered automaticity, conduction system injury or treatment side effects
Suspect in known<unk>  with mild rhythm disturbances, CHF or myocardial fibrosis
Causes include reentry pathways, fibrosis, altered automaticity, conduction system injury or treatment side effects
Fever, malaise, fatigue, weight loss
High association with malignancy
Dermatomyositis
Infection:
Polymyositis
Viral infection 
Pyomyositis
Bacterial infection
Lambert-Eaton myasthenic syndrome
Spirochete infection 