Muscle diseases Flashcards
Polymyalgia rheumatica - Definition
Common chronic inflammatory condition
Associated with temporal arteritis and giant cell arteritis
Polymyalgia rheumatica - epidemiology
age
Over 50 year olds
Polymyalgia rheumatica - clinical features
Ache in the shoulder / hip girdle
Usually symmetrical
Morning stiffness - “struggle to get out of bed”
Symptoms improve as the day goes on
Reduced movement of the shoulders, neck and hips
Muscle strength is normal
Polymyalgia rheumatica - investigations
No specific diagnostic test
Bloods
- raised inflammatory markers
Polymyalgia rheumatica - management
Low dose steroids
- 15mg prednisolone
- patient should have a very rapid and dramatic response
Polymyalgia rheumatica - Giant cell arteritis (GCA) Definition
Most common form of systemic vasculitis in adults
Polymyalgia rheumatica - GCA epidemiology
age
Older patients
Polymyalgia rheumatica - GCA pathogenesis
Transmural inflammation of the affected arteries
Patchy inflammation of lymphocytes, macrophages and giant nucleated cells
Vessel wall thickening can cause narrowing of the lumen of the artery. This leads to ischaemia
Polymyalgia rheumatica - GCA commonly affected areas
Head - temporal artery
vertebral artery,
Ophthalmic artery
Polymyalgia rheumatica - GCA clinical features
Visual disturbances Continuous headache Jaw claudication Scalp tenderness Tender enlarged non-pulsatile temporal arteries
Polymyalgia rheumatica - GCA examination
Can’t feel temporal pulse as the wall of the artery has become thickened
Polymyalgia rheumatica - GCA investigations
Bloods
- raised inflammatory markers
Temporal artery biopsy
- mononuclear infiltration of granulomatous inflammation usually with multi-nucleated giant cells
Polymyalgia rheumatica - GCA management
High dose steroids
- 40-60mg prednisolone
Polymyositis - definition
Idiopathic inflammatory myopoathy that causes symmetrical proximal muscle weakness
Polymyositis - epidemiology
M/F, malignancy
More common in females
increased incidence of malignancy
Polymyositis - pathogenesis
CD8+ T cells and macrophages initially surround the healthy muscle fibres and eventually invade and destroy them
Polymyositis - Histology
Muscle fibre necrosis
Degeneration
Loss of inflammatory cells
Polymyositis - clinical features
Muscle weakness
Muscles feel tired and heavy
Difficulty with particular activities (climbing stairs)
Other organ involvement (i.e. ILD, dysphagia)
Polymyositis - associated medical conditions
Diabetes
Thyroid disease
Polymyositis - associated medication
Statins
Steroids
Polymyositis - examination
Look for muscle wasting
Dermatomyositis - definition
Clinically similar to polymyositis but also has typical skin manifestations
Dermatomyositis - clinical features
Muscle weakness
Heliotrope rash - violet coloured rash around the eye
Shawl sign
V shaped rash over chest
Grottos sign - pink/purple colour, affects hand joints
Polymyositis & dermatomyositis - investigations
Bloods - raised inflammatory markers - raised creatinine kinase (indication of muscle b/d) Auto-antibodies - ANA raised - +ve anti-Jo-1 (specific) MRI - shows extent of muscle involvement EMG - Looks at muscle function by assessing conduction Biopsy - gold standard
Fibromyalgia - definition
Unexplained condition causing widespread muscle pain and fatigue
Fibromyalgia - epidemiology
M/F, age
More common in females
Age: 22-50
Fibromyalgia - risk factors
Stress
Physical trauma
IBS
Fibromyalgia - pathology
Disorder of central pain processing or a syndrome of central sensitivity
Patients have a lower pain threshold
Fibromyalgia - clinical features
Widespread pain Persistent pain (>3 months) Fatigue Cognitive difficulties Symptoms worsen on exertion Pins and needles sensation Headache Depression
Fibromyalgia - examination
Excessive tenderness on palpation of soft tissues
Fibromyalgia - commonly affected areas
Neck
Shoulders
Lower back
Fibromyalgia - investigations
No diagnostic tests
Multiple normal investigations
Fibromyalgia - management
Anti-depressants (amitryptiline)
Analgesia
Gabapentin
