Polymyositis

Question 1

Prevalence

Answer 1

• not very common
• but often missed in practice when presented as chronic lameness or lethargy secondary to generalised pain

Question 2

CS, aetiology

Answer 2

• generalised myalgia (muscle pain)
• usually idiopathic autoimmune
• can be coexisting with other autoimmune presentations such as polyarthritis

Question 3

Diagnosis

Answer 3

• likely to show marked CPK on bloods
• definitive diagnosis on muscle biopsy

Question 4

Tx

Answer 4

• extended course of corticosteroids at an immunosuppressive dose