Rheum - muscle pain diseases Flashcards
describe the presentation of polymyositis and dermamyositis. explain why these occur.
Autoimmune inflammation of striated muscle (+/- skin) causing insidious onset of:
- proximal muscle weakness
- +/- shortness of breath (resp. muscles/diaphragm weakness)
- +/- swallowing probs. (striated muscle in upper oesophagus) risk of aspiration pneumonia)
- systemic symptoms, e.g. fatigue, fever, weight loss, Raynaud’s syndrome
- +/- periorbital oedema
- if dermatomyositis: rash
describe the appearance of the rash in dermatomyositis
- photosensitive
- initially appears in light exposed areas such as scalp, face and neck +/- upper outer thighs
- forms linear plaques on dorsal aspects of hands (Gottron’s papules)
- periungal erythema
- +/- heliotrope rash (violet rash to eyelids, less common)
describe the diagnostic criteria for polymyositis and dermatomyositis
- symmetrical proximal muscle weakness
- raised serum muscle enzymes, e.g. CK
- typical electromyographic changes
- biopsy evidence of myositis
- typical rash of dermatomyositis
PM if 3+ of 1st 4 criteria.
DM if rash + 2+ of 1st 3 criteria.
which investigations are used to Dx polymyositis and dermatomyositis?
- Bloods
- raised serum muscle enzymes: CK, ALT
- auto-Abs: ANA +ve, anti-Jo-1 +ve (ask for extended muscle auto-Ab panel) - Biopsies
- muscle (for PM and DM)
- skin (for DM) - Imaging
- MRI of muscle
- barium swallow if dysphagia
- EMG
suggest possible complications/associated conditions of DM and PM. How would you investigate these?
- malignancy (increased risk in 2-3 yrs before and afer Dx) - PET/CT scan
- ILD - CXR and PFTs
- Tachyarrythmias, dilated cardiomyopathies, etc. - ECG and echo
How would you manage a pt with DM/PM?
Initial Mx:
i) High dose corticosteroids - prednisolone for 1st few wks
ii) IV immunoglobulins if no response to steroids
Long term:
i) Sun protection
ii) Methotrexate (and/or azathioprine or mycophenolate mofetil)
iii) Rituximab if no response
what is fibromyalgia? how does it present?
Common disorder of central pain processing characterised by chronic widespread pain in all 4 quadrant of body. Allodynia (heightened and painful response to innocuous stimuli) often present.
Presentation:
- joint/muscle pain and stiffness
- profound fatigue
- headaches, poor concentration, depression and anxiety
- irritable bowel/bladder syndrome
what is polymyalgia rheumatica? who and how does it typically present?
Clinical syndrome characterised by pain and stiffness of shoulders, hip girdles and neck.
Incidence increases with age with average age of onset 70 yrs.
Typical Hx:
- elderly pts with new onset proximal limb pain and stiffness, e.g. difficulty rising from chair or combing hiar
- night time pain
- systemic Sx in 25% (fatigue, weight loss, low-grade fever)
how is Dx of PMR made?
- typical Hx and examination
- decreased ROM of shoulders, neck and hips
- muscle tenderness
- normal muscle strength - Bloods
- raised ESR and CRP - Dramatic/diagnostic response to steroids
how is PMR treated?
i) 15 mg prednisolone daily (about 18mths) is effective in almost all pts - expect dramatic response within 5 days. Then tapered very slowly.
ii) Methotrexate can be steroid-sparing in relapsing pts.
