Myositis Referral Guideline

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Idiopathic inflammatory myopathies (myositis) are a varied group of rare autoimmune diseases, mainly characterised by inflammation of the skeletal muscles, but involvement of skin and internal organs such as lungs, heart, and oesophagus is common.

Patients presenting with acute/subacute proximal muscle weakness and more than 10 fold increase in creatinine kinase (not explained by alternative, more likely cause – see below) should be referred to rheumatology urgently.

History & Examination

  • Proximal muscle weakness/tetraparesis which can develop acutely (several days) or subacutely (several weeks up to a few months) and can be associated with at least one of the following:
    • Typical skin lesions such as:
      • Gottron papules on the dorsal aspect of the hands and fingers,
      • Periorbital oedema and erythema of the face (heliotrope rash),
      • Rash on the anterior upper chest (V-sign) or the posterior neck (shawl sign),
      • Periungal erythema and telangiectasia,
      • Thickened and cracked skin of the ventral and dorsal aspects of the fingers and hands (“mechanic’s hands”),
      • ! in an amyopathic dermatomyositis there are only skin manifestations but there is no weakness of the muscles and no increase of the CK.
    • Dysphagia
    • Interstitial lung disease
    • Raynaud’s syndrome
    • Sicca syndrome
    • Arthritis.
    • In overlap syndromes, can be associated with any manifestation of other connective tissue disorders (Systemic sclerosis, SLE, Sjögren syndrome).
    • Malignancy (lung, breast, ovary, lymphoma).

Helpful Investigations

  • CK 10–50 fold increase and elevated liver enzymes

! consider CK normal values differences (race, gender).

! CK can be elevated post excessive exercise (repeat after one week of rest).

  • Raised CRP +/- ESR
  • FBC, U&E, LFTs
  • TFT
  • ANA

Primary Care Management

Manage symptoms pending rheumatology clinic review.

Who to Refer

All patients with acute or subacute onset of symmetrical proximal muscle weakness with elevated CK 10–50 fold and raised CRP/ESR require urgent referral.

Who Not to Refer

  • Patients with diffuse myalgia and normal blood tests including CK and inflammatory markers.
  • Patients with chronic pain syndromes with no new signs or symptoms and normal blood tests.
  • Patients with alternative diagnosis/cause of elevated CK more likely, e.g.
    • Viral infections
    • Endocrine disorders
    • Liver, cardiac and renal diseases
    • Metabolic diseases
    • Coeliac disease
    • Drug induced myopathy
    • Pregnancy
    • Surgery
    • Trauma or recent physical exercise
    • Motor neuron disease
    • Myasthenia gravis
    • Muscular dystrophy.

Last reviewed: 01 November 2020

Next review: 01 November 2022

Author(s): Dr Anna Ciechomska

Co-Author(s): Rheumatology team: Dr Robin Munro, Dr Karen Donaldson, Dr Elizabeth Murphy, Dr James Dale, Dr Sanjiv Nandwani, Dr Georgiana Young, Dr May Chee, Mr Nico Groenendijk; GP representatives: Dr Tyra Smith, Dr Mark Russell, Dr Linda Findlay, Dr Paul Deehan, Dr Lucy Munro; Medical directorate: Dr Mehrdad Malekian

Approved By: Dr Karen Donaldson

Reviewer Name(s): Dr Anna Ciechomska