Flashcards in MSK soft tissue pathology Deck (78):
What are the indications of muscle disease?
Raised creatinine kinase
Describe the patterns of serum creatinine kinase level with respect to pathology
Raised 200x - muscular dystrophy
Raised 20x - inflammatory myopathy
Decreased 2x - neurogenic
How can we categorise the two types of muscle pathology?
Neurogenic disease causing muscle pathology
List the different categories of myopathy
Which age group presents with duchenne's muscular dystrophy?
2-4 year olds
How is duchenne's muscular dystrophy inherited?
X-linked (so only males)
What is the average life expectancy for someone with duchenne's?
20 years old
How does duchenne's muscular dystrophy present?
Proximal muscle weakness
Pseudohypertrophied calf muscles
How will creatinine kinase be affected in duchenne's?
What gene is affected in DMD? What does this result in?
Poor cytoskeleton anchorage to the basement membrane and thus muscle tearing
How does DMD appear histologically?
Necrosis & regeneration
Chronic inflammation & fibrosis
What is becker's muscular dystrophy?
A less severe variant of DMD
When does becker's muscular dystrophy (BMD) present?
Later than DMD
How fast does BMD progress?
What gene is affected in BMD?
Dystrophin (less severe mutation than DMD)
What are the two types of myotonic dystrophy? How can they be clinically differentiated?
DM1 - distal muscles affected
DM2 - proximal muscles affected
How does myotonic dystrophy present?
Myotonia (inability to relax muscle)
What are the extra muscular features of myotonic dystrophy?
Frontal baldness (males only)
How is myotonic dystrophy inherited? Which chromosome does it affect?
C19 & C3
Describe the natural history of myotonic dystrophy
Young patients - face and distal limbs affected
Older patients - respiratory muscles affected
How does myotonic dystrophy present histologically?
Type 1 (red) muscle cell atrophy
What are the three main types of inflammatory myopathies?
What is polymyositis?
A chronic inflammatory disease of the muscles
How does polymyositis present?
Progressive muscle weakness
Describe the immunological component of polymyositis
Cell mediated immune response (lymphocytic and CD8 T cells) to muscle
How does polymyositis present histologically?
Segmental fibre necrosis
What is dermatomyositis?
Polymyositis plus skin changes
What is dermatomyositis associated with?
Describe the immunological component of dermatomyositis
Immune complex deposition in muscle capillaries (CD4 T cells and B cells)
What are neurogenic disorders of the muscle?
Nerve damage resulting in disorders of the muscle following re-innervation
List the categories of neurogenic muscle disorders
Motor neurone disease
Spinal muscular atrophy
Misc. spinal disorders
How do the muscle fibres appear histologically with respect to neurogenic muscle disorders in adults and children respectively?
Adults - small and angulated
Children - small and round
Fibre type grouping and atrophy
What is motor neurone disease?
Progressive degeneration of anterior horn cells
How does motor neurone disease present (generally)?
Muscle atrophy (due to denervation)
How is spinal muscle atrophy inherited? Which chromosome is affected?
What is spinal muscle atrophy?
Degeneration of the anterior horn cells within the spinal cord causing denervation of muscle
What is myasthenia gravis?
An autoimmune condition against post synaptic acetylcholine receptors
How does myasthenia gravis present?
Who gets myasthenia gravis?
What is associated with myasthenia gravis?
How can myasthenia gravis be treated?
What is rhabdomyolysis?
Skeletal muscle breakdown
What biochemical changes does rhabdomyolysis cause?
Raised myoglobin (coca cola urine)
What complications can arise from rhabdomyolysis?
Acute kidney injury --> hypovolaemia
Disseminated intravascular coagulation
Are connective tissue diseases more common in males or females?
How can connective tissue diseases be treated?
What is systemic lupus erythmatosus?
Multi-system autoimmune condition
Which antibodies are positive in SLE?
ANA (anti nuclear antibodies)
Is SLE genetic?
It can play a part in inheritance
Which two drugs can cause SLE?
What are the dermatological manifestations of SLE?
Malar butterfly rash
Discoid lupus erythematosis
How does SLE affect the joints?
How does SLE affect the kidneys?
How does SLE affect the nervous system?
How does SLE affect the CVS?
Can SLE present with lymphadenopathy?
How does SLE affect the lungs?
How does SLE affect the haematological system?
Leucopenia (low white cells)
Thrombophilia (inc. clotting risk)
What two types of hypersensitivity are at play with regard to SLE?
Visceral - immune complex mediated (type III)
Haematological - type II
What is polyarteritis nodosa?
Inflammation and necrosis of small to medium arteries
Which organs are commonly affected by polyarteritis nodosa?
How might polyarteritis nodosa present?
Secondary hypertension (from kidneys)
What can be found on biopsy of polyarteritis nodosa?
What antibody is positive in polyarteritis nodosa?
Who gets polymyalgia rheumatica?
How does polymyalgia rheumatica present?
Pain and stiffness in shoulder and pelvic girdle
NO muscle weakness
How is polymyalgia rheumatica treated?
What is temporal arteritis?
Vasculitic inflammation of the cranial vessels
What is the risk with temporal arteritis?
How is temporal arteritis investigated?
Raised inflammatory markers
Temporal artery biopsy (skip lesions)
What is scleroderma?
Excessive collagen deposition (fibrosis) of organs/tissues
How does scleroderma affect the skin?
Tight immobile skin
How does scleroderma affect the GI tract?
Fibrosis of muscles (dysphagia, etc)
How does scleroderma affect the CVS?
Myocardial fibrosis --> HF/arrhythmias
How does scleroderma affect the lungs?
How does scleroderma affect the kidneys?
Attacks blood supply --> secondary hypertension --> CKD
How does scleroderma affect the MSK?