57 - Diseases of musculoskeletal system Flashcards
Acute arthritis presentation
Pain, heat, redness and swelling
Chronic arthritis presentation
Commonest - osteoarthritis & rheumatoid
Osteoarthritis -
Commonest type of joint disease aka degenerative
Progressive erosion of articular cartilage resulting in bony spurs and cysts in joint margins
Osteoarthritis (OA) - pathogenesis (mechanical)
Deterioration or loss of cartilage
As cartilage is worn away it forms spurs and fluid filled cysts appear in the marrow (subchondral cysts)
Results in pain and limited movements
Osteoarthritis (OA) - pathogenesis (biological)
Chrondrocytes produce IL-1 and initiate matrix breakdown.
Prostaglandin derivatives induce the release of lytic enzymes - preventing matrix synthesis.
Osteoarthritis (OA) - primary OA
Abnormal stressed in weight bearing joints - fingers, knees, cervical + lumbar spines
Fingers -> Herberden’s or Bouchard’s nodes
Rheumatoid arthritis - what is it?
Chronic systemic disorder
Producing non suppurative proliferative synovitis - destruction of articular cartilage and ankylosis of joints
Affects skin, muscles, heart lung and blood vessels (woman 3-5 times more than men)
Rheumatoid arthritis - pathogenesis
Polypoid fibrovascular thickening of synovium with hyperplasia, producing pannus that erodes articular cartilage.
Growth penetrates subchondral bone and cysts form .
Joint fills producing ankylosis of joint space
Rheumatoid arthritis - clinical feature
Malaise, fatigue + general MSK pain
Involved joints: swollen, warm, painful and stiff in morning or after activity.
Slow or rapid
Rheumatoid arthritis - pathogenesis
Genetic susceptibility Primary exogenous arthritogen Autoimmune Cytokine problems IL-1,6 and TNF alpha and beta
Rheumatoid arthritis - diagnosis criteria
morning stiffness arthritis in 3 or more joint areas arthritis in hand joints Symmetric arthritis Rheumatoid nodules Serum rheumatoid factors
Radiographic presentation
Rheumatoid factor - present in most
Analysis of synovial fluid - confirms presence of neutrophils (hence inflammatory)
Sero-negative arthritides
Lack rheumatoid factor:
- ankylosing spondylitis
- reiter’s syndrome
- psoriatic arthritis
- enteropathic arthritis
Gout -
hyperuricemia
uric acid is the end produce of purine metabolism
caused by enzyme deficiencies
Gout - clinical features
Acute arthritis
Chronic arthritis
Tophi in various sites
Gouty nephropathy
Pyogenic osteomyelitis - clinical presentation
Systemic illness - fever, malaise, chills and marked pain over region
Pyogenic osteomyelitis - investigations
X ray - lytic focus of bone destruction surrounded by zone of sclerosis
Blood cultures are positive
Biopsy
Pyogenic osteomyelitis - pathogenesis
Caused by bacteria
Haematogenous
Extension from a contiguous site
Direct implantation
Infective arthritis -
acutely painful and swollen joints with restricted movements
Infective arthritis - clinical presentation
fever, leucocytosis and elevated ESR
Infective arthritis - bacterial
Staph, strep, gonococcus, mycobacteria
Infective arthritis - predisposing factors
Trauma, IV drug abuse, debilitating illness
Osteoporosis -
Increased porosity of the skeleton
Reduction in bone mass
Localised or entire skeleton
Primary or secondary
Osteoporosis - risk factors
Physical activity
Muscle strength
Diet
hormonal status
Osteoporosis - clinical features
Vertebral fractures
Kyphosis
Scoliosis
Secondary Osteoporosis - clinical features
Endocrine disorders - hyperparathyroidism, Type 1 diabetes
Neoplasia - multiple myeloma
Malnutrition
Paget’s disease -
Disease of collagen matrix
Caused by paramyxovirus
Paget’s disease - problems with which thing
Predominant osteoblastic activity with burnt out osteosclerotic phase
Net effect is gain in bone mass
Paget’s disease - epidemiology
Begins in 50s
M>F
Paget’s disease - clinical presentation
pain most common
chalk stick type fractures
Paget’s disease - tumours
Benign and malignant
Giant cell - benign
Malignant - osteosarcoma, chrondrosarcoma, malignant fibrous histiocytoma
Osteomalacia -
Defects in matrix mineralisation
Lack of vit D
Decreased bone density and too little bone - osteopenia
Hyperparathyroidism - pathogenesis
Excessive secretion of PTH
Increases bone resorption and Ca mobilisation from the skeleton
Increaces renal tubular reabsorption and retention of calcium
=== hypercalcaemia
Causing osteitis fibrosa cystica - loss of bone mineral with osteoporosis
Renal osteodystrophy -
Skeletal changes of chronic renal disease: Increased osteoclastic bone resorption Delayed matrix mineralisation Osteosclerosis Growth retardation Osteoporosis
Lipomas are
fat tissue
fibromas are
fibrous tissue
leiomyomas
smooth muscle
heamangiomas
blood vessel
lymphangiomas
lymphatics
neuromas
peripheral nerves
soft tissue tumour syndrome
neurofibromatosis type one - neurofibroma
gardner syndrome - fibromatosis
carney syndrome - myxoma, melanotic schwannoma
turner syndrome - cystic hygroma
Soft tissue tumour diagnosis
US guided core biopsy
Wide excision
Cytogenetics - culture of fresh tissue and karyotypic analysis
Molecular genetics - FISH, PCR and RT-PCR
Bone tumours
from bone and cartilage
benign bone tumours
osteomas, osteoblastomas
benign cartilage
chrondromas
mixed
osteochondromas
malignant bone tumours
osteosarcoma
young age group - around knee
other bone tumours
chondrosarcomas
Ewing’s sarcoma
Giant cell tumours
Where do bones met to?
Thyroid, prostate, kidney, breast, GI tract
Systemic lupus erythematosus -
Complex multi system disease
Predominantly cutaneous
F>M
Systemic lupus erythematosus - clinical presentation
Cutaneous - butterfly rash - typically affecting bridge of nose and the cheeks
Cardiac - cardiomegaly, endocarditis
CNS - convulsions, hemiplegia
Renal - 45% of patients, nephrotic syndrome and glomerulonephritis
Systemic sclerosis - pathogenesis
complex and poorly understood
Systemic sclerosis - what is it?
vessel damage, inflam response and cytokines
Systemic sclerosis - clinical presentation
Diffuse-widespread cutaneous lesions
Renal, cardioresp and GI tract
Osteoarticular involvement - artharlgia and arthritis
Systemic sclerosis - prognosis
poor
Systemic sclerosis - localised variant
Limited cutaneous involvement, oesophageal involvement and SI malabsorption
CREST syndrome
CREST syndrome stands for
Calcinosis Reynaud's Oesopageal dysfunction Sclerodactyly Telangiectasia
Polymyalgia rheumatica - clinical presentation
stiffness, weakness, aching and pain in neck, limb girdles and upper limbs
associated with giant cell arteritis - occipital and facial arteries. Causing pyrexia, headache and severe scalp pain.
Polymyalgia rheumatica - pathogenesis
immunological mechanism
Myopathy definition
muscle disease unrelated to any disorder of innervation or neuromuscular junction
Myositis definition
muscle fibres and overlying skin are inflamed and damaged resulting in muscle weakness
Muscular dystrophy - what is it?
heterogenous group
inherited
progressively severe muscle weakness and wasting
begins in childhood
Malignant hyperthermia - what is it?
inherited
fast rise in body temperature and severe muscle contraction when the affected person general anaesthesia
rhabdomyolysis - what is it?
destruction of skeletal muscle releasing muscle fibre content into blood e.g. myoglobin
rhabdomyolysis - urine
myoglobin filtered through kidney and enters urine - myoglobinuria - brown urine
rhabdomyolysis - causes
trauma, crush injuries drugs - cocaine, amphetamine extreme temp severe exertion (marathon) length surgery severe dehydration
rhabdomyolysis - complications
acute renal failure
metabolic myopathies
glycogen synthesis and degradation
disorders of mitochondrial metabolism
malignant hyperthermia - signs and symptoms
bleeding dark brown urine muscle rigidity quick rise in body temp to 105 deg F discovered during anaesthesia may have FH
