Muscle Diseases Flashcards
what characterises inflammatory myopathies
weakness
what characterises polymyalgia rheumatica
pain and stiffness
what characterises fibromyalgia
pain and fatigue
what is myopathy
a disease in which the muscle fibres don’t function properly
what is polymyositis
idiopathic inflammatory myopathy that causes symmetrical, proximal muscle weakness
what is dermatomyositis
polymyositis + typical cutaneous manifestations
which gender is more likely to get polymyositis
females
peak incidence age of polymyositis
40-50
pathophysiology of polymyositis
CD8+ T cells and macrophages surround, invade and destroy healthy, non-necrotic muscle fibres
symptoms of polymyositis
symmetrical, proximal muscle weakness in the upper and lower extremities
often present with a specific problem
insidious onset
clinical sign of polymyositis
muscle wasting
name 2 types of examination tests you can do for polymyositis
confrontational and isotonic testing
confrontational testing for polymyositis
comparing your strength to the patient’s
isotonic testing for polymyalgia
30 second sit to stand
3 derm signs of dermatomyositis
hellitrope rash
gottrons sign
shawl sign
what is gottrons sign
red/purple plaques on the back of the fingers, elbows or knees
name some other signs of organ involvement you may see in polymyositis
ILD, dysphagia, myocarditis, raynauds
bloods to investigate polymyositis
creatine kinase (largely raised)
inflammatory markers
autoantibodies
myositis specific autoantibodies
anti-jo-1
ant-SRP
name some non-specific autoantibodies that may be positive in myositis
ANA, anti-RNP
what is used to localise muscle involvement in polymyositis
MRI
what is a definitive test for polymyositis
muscle biopsy
biopsy of polymyositis shows…
perivascular inflammation and muscle necrosis
1st line management of polymyositis
prednisolone
name 2 complications of polymyositis
increased risk of malignancy
anti-synthetase syndrome
what is fibromyalgia
a neurosensory disorder characterised by chronic MSK pain
what is the most common cause of MSK pain in women 22-50
fibromyalgia
what can cause fibromyalgia to begin
emotional or physical trauma
clinical presentation of fibromyalgia
persistent widespread pain
fatigue
headaches
anxiety, depression
non-cardiac chest pain
how do we diagnose fibromyalgia
clinical diagnosis of exclusion
management of fibromyalgia
graded exercise programme
CBT
accupuncture
what is myasthenia gravis associated with
other autoimmune conditions: SLE, rheumatoid arthritis, thyrotoxicosis
most common age of presentation of myasthenia gravis
60-70
tumour associated with myasthenia gravis
thymic tumour
what kind of reaction is myasthenia gravis
type 2 hypersensitivity
clinical presentation of myasthenia gravis
insidious onset,
initial complaint involves ocular muscles
fatigue and progressive muscle weakness
testing for myasthenia gravis
anti-AChR IgG in serum
first line management of myasthenia gravis
anticholinesterases
what is myonecrosis
necrotising soft tissue infection caused by the proliferation and spread of c.perfringens from a contaminated wound
clinical presentation of myonecrosis
disproportionate muscle pain
oedema and skin discolouration (bronze-red/purple-black
imaging of myonecrosis
shows a feathering pattern of the soft tissue
management of myonecrosis
immediate surgical debridement and antibiotic therapy
what is pyomyositis
acute intramuscular infection
most common cause of pyomyositis
staph aureus
name 3 risk factors for pyomyositis
PWIDs
DM
immunosuppressed
clinical presentation of pyomyositis
fever
pain and swelling in the affected area (usually lower extremities)
management of pyomyositis
surgical debridement and antibiotics
give some viruses that can cause viral myositis
influenza, enterovirus, HIV, CMV
clinical presentation of viral myositis
pain, tenderness and swelling of muscle
a few days after the onset of a fever
bloods in viral myositis
elevated CK
what causes tetanus
c.tetani toxin
