In station 5 you may be asked to assess a patient with weakness (and a rash).
HISTORY (3 minutes)
- Muscle weakness
- Timing (sudden/gradual, progression, intermittent/constant, previous episodes, since when, worse at particular time of day)
- Which muscles (proximal/distal, uni/bilateral)
- Proximal: Rising from a chair, going up stairs, lifting, brushing hair,
- Distal: doing buttons, writing (should be spared in polymyositis)
- Any change in your voice, any difficulty swallowing/breathing
- Any facial weakness, any change in vision (not in polymyositis), any eyelid drooping
- Neuro Q: sensation etc.
- Muscle pain/ache/cramp (usually not in polymyositis)
- Skin: Rashes, nail changes, photosensitivity
- Systemic features (extramuscular/dermatological)
- Constitutional: tiredness, weight loss, anorexia, fever, sweats
- Joint pains/swelling/stiffness
- Resp: SOB, CP, cough
- GI: reflux, bowels, abdo pain
- Cardiac: CP, palps, syncope, ankle swelling
- Extra connective tissue disease questions:
- Raynauds, hair loss, ulcers, dry eye/mouth, red eye etc.
- Assess for cancer eg:
- Breast checks
- Haemoptysis
- Jaundice, abdo pain, bloating
- PR bleeding/PV bleeding
- Lumps/bumps
- Exclude Polymyalgia rheumatica (pain and stiffness) and Giant cell arteritis: headache, scalp pain, jaw pain on chewing, visual disturbance
- PMH: connective tissue disease/joint problem/autoimmune problem, recent infections, cancer, diabetes/thyroid, renal/liver
- Fx: connective tissue disease, autoimmune problem, muscle problem
- Dx: statins, steroids
- Sx: alcohol, occupation
EXAMINE (3 minutes)
- Power (MRC grade) and palpate muscles for bulk and tenderness. Ask patient to rise from sitting with arms crossed
- Full neuro examination including neck flexion/extension, cranial nerves (especially CNs 3,4,6,7) and fatiguability check
- Skin: face, trunk, hands and nails, limbs
- Systemic: Lymph nodes, CVS, Resp, Abdo, Thyroid. Offer Breast exam, PR, PV if indicated.
- Joints (synovitis)
- Palpate temporal arteries if suspicion of GCA from history
- Any evidence of autoimmune disease eg. vitiligo, diabetes etc or other connective tissue disease eg. scleroderma, lupus
- Patient may appear Cushingoid from steroid use.
ICE and Explanation (2 minutes)
VIVA
Polymyositis: 50-60 mean age of onset. Inflammation of skeletal muscle fibres.
Dermatomyositis: 5-15 year olds, 45-65 year olds (polymyositis and rash)
Females> males
Proximal motor weakness
- Gradual onset, symmetrical, progressive
- Shoulder, neck, pelvis. Can get dysphonia, dysphagia, SOB
- Not eye/face/distal muscles
- Minimal pain
Dermatomyositis:
Skin:
- Heliotrope rash and oedema: eyelids, nasolabial folds, malar region, forehead
- Gottrans papules: flat/raised, purple-red papules on knuckles, extensor surfaces eg. elbows, knees
- V sign rash- chest and neck
- Shawl sign rash- shoulders and proximal arms. Exacerbated by sunlight.
- Holster sign rash- proximal thighs laterally
- Mechanics hands- radial side of index finger
- Nailfold abnormalities- periungal erythema, dilated capillary loops
Extramuscular/dermatological:
- Constitutional symptoms
- MSK: arthralgia/arthritis
- Resp: Interstitial lung disease, aspiration pneumonia, pulmonary hypertension
- GI: oesophageal dysmotility, reflux, rectal incontinence
- Cardiac: dysrhythmia, heart block, myocarditis
- Vascular: raynauds, skin ulcers
Association with Cancer:
- 10-20%
- >50% if over 65 years old
- Dermatomyositis > polymyositis
- Usually within 3 years of myositis onset
- Breast, lung, pancreas, stomach, colon, ovary, lymphoma
- Cancer screen: FOB, CXR, mammogram, abdo/pelvic CT, tumour markers (PSA, CEA, CA125, CA19-9, CA15-3). If negative, rescreen in 3-5 years. Annual examination.
Antisynthetase syndrome (anti-jo-1):
- Myositis
- Interstitial lung disease
- Raynauds
- Symmetrical nonerosive small joint arthritis
- Mechanics hands
- Occasional fever
Differential diagnosis of “weakness”:
- Neuromuscular: cord/plexus/root/nerve/NMJ (eg. myasthenia gravis, motor neuron disease, Guillain Barre syndrome)
- Muscular (myopathies)
- Inflammatory: polymyositis/dermatomyositis. NB: can overlap with other connective tissue disease eg mixed connective tissue disease
- Other connective tissue disease eg. SLE, vasculitis, RA, systemic sclerosis.
- Cancer (paraneoplastic: carcinomatous neuromyopathy)
- Drugs (statins, steroids)
- Infections (bacterial infections, HIV, CMV, EBV, Hepatitis)
- Endocrine (thyroid, addisons, osteomalacia, cushings, acromegaly, diabetic amyotrophy)
- Toxins (alcohol)
- Metabolic (renal/liver failure, electrolyte disturbance)
- Miscellaneous (inclusion body myositis, rhabdomyolysis, sarcoidosis, mitochondrial myopathy, muscular dystrophy)
- Other (not true weakness)
- Polymyalgia rheumatica (pain and stiffness) +/- giant cell arteritis
- Fibromyalgia (pain, fatigue, stiffness, sleep disturbance)
- OA/rotator cuff problem (muscular atrophy and weakness secondary to joint pain)
- Fatigue/malaise/depression
Investigations:
- Bloods
- Routine (FBC, U+E, LFT, Ca, P, Mg)
- Rheumatological screen: ESR (normal/increased), CRP (normal usually), ANA (50-80%), ANCA, RF, anti-CCP, ‘myositis blot’ (myositis associated antibodies eg. anti-RNP, Anti-Pm-Scl, Anti-Ku, anti-Ro) and myositis specific antibodies eg. antisynthetase/anti-jo-1, anti-SRP, anti Mi2), immunoglobulins, complement
- CK, AST, ALT, LDH (all raised)
- TFTs, vitamin D and bone profile, HBa1C, cortisol, HIV, Hepatitis screen, CMV/EBV/adenovirus, serum ACE
- Urine dip and urine PCR
- Nerve conduction studies (normal) and EMG (myopathic changes)
- MRI muscle eg. thigh (inflamed muscle)
- Muscle biopsy eg. thigh (inflammation) +/- skin biopsy
- Cancer screen: FOB, CXR, mammogram, CT, tumour markers (PSA, CEA, CA125, CA19-9, CA15-3)
- Joint xray/USS
- Systemic assessment: ECG, CXR, Echo, lung function tests, HRCT, OGD/colonoscopy/barium swallow
Management:
Dermatology review, avoid sunshine, suncreams
Rheumatology review
SALT
Physiotherapy
Steroids- prednisolone high dose (60mg) daily. Monitor power and CK. Gastro and bone protection. Once in remission taper and monitor for recurrence
Steroid-sparing agents: methotrexate, azathioprine, mycophenolate mofetiil, cyclophosphamide
IVIG
Rituximab
Treat malignancy
Written by Dr Sarah Kennedy
Resources used to write this document include those listed in the references section of this webpage and also:
Rheumatology Secrets by Sterling West