Pathology - MSK Flashcards
Which enzyme is commonly raised in muscle disease?
Creatinine kinase
How raised is CK in dystrophic muscle disease?
High, 200-300x normal
How raised is CK in inflammatory muscle disease?
Medium, 20-30x normal
How raised is CK in neurogenic muscle disease?
Low, 2-5x normal
Muscle pathology can be split into 2 distinct groups - what are they?
Pathology affecting the muscle itself
Pathology affecting nerve supply to muscle
Describe some dystrophic muscle changes
Varied muscle fibre size
Nuclei centrally placed
Endomysial fibrosis
Fatty infiltrate
Duchenne and Becker muscular dystrophy has which genetic inheritance? Which area of the body do they primarly effect?
X-linked recessive
Pelvic girdle
What age does Duchenne’s MD usually affect?
2-4yrs
Die by 20
What is the pathology behind Duchenne’s MD?
Alterations in anchorage of actin cytoskeleton to basement membrane (fibres weakened without attachment)
Becker MD is a genetic variant of Duchenne’s MD with an earlier onset. True/False?
False
Later onset
Which muscular dystrophy is the commonest? Which inheritance pattern does it follow?
Myotonic
Autosomal dominant Ch19 and Ch3
Myotonic dystrophy exists in 2 forms: MD1 and MD2. MD1 affects proximal/distal and MD2 affects proximal/distal
MD1 affects distally
MD2 affects proximally
What is polymyositis?
Progressive muscular dystrophy caused by chronic inflammation of unknown cause
What is dermatomyositis?
Polymyositis with skin changes
Associated with malignancy in 10%
What is myasthenia gravis?
Autoimmune disorder where antibodies are made against ACh, resulting in muscle weakening and dysfunction
