Diseases of MSK 1 Flashcards
Features of Osteoarthritis
Erosion of articular cartilage
Bony spurs form
Aging phenomenon
Is Osteoarthritis common?
Commonest type of joint disease
What is secondary OA?
Not caused by ageing
Knee in basket ball players and elbow in baseball players
Underlying systemic diseases such as diabetes and marked obesity
Knees and hands in women and hip in men
OA Pathogensis
Deterioration of cartilage
As the cartilage is worn away-bone forms spurs and fluid filled cysts
Results in pain and limitation of movements
Cellular basis of OA
Chondrocytes–> IL1 –> Prostaglandin –>s lytic enzymes Matrix breakdown
Causes of primary OA
Abnormal stresses in weight bearing joints
Features of primary OA
Affects fingers, knees and cervical and lumbar spines
Involvement of fingers- Herberden’s or Bouchard’s nodes
Features of RA
Chronic
Producing a non suppurative synovitis- (destruction of articular cartilage and ankylosis of joints)
Also affects skin, muscles, heart, lungs and blood vessels
Pathogenesis of RA
Fibrovascular thickening in synovium –> Synovial hyperplasia –> Pannus forming –> Pannus invades into articular cartilage –> Cartilage eroded and bone penetrated –> Joint space fills with pannus causing ankylosis
Genetic and viral causes for RA
Genetic susceptibility-65-80%- HLA- DR4 &DR1 or both
Autoimmune reaction within the synovial membranes- CD4 positive T-cells
Mediators of joint damage- Cytokines-
IL-1-6 and TNF-alpha&beta
Primary exogenous arthritogen- EBV,other viruses, Borrelia
Criteria for RA diagnosis
Morning stiffness Arthritis in 3 or more joint areas Arthritis of hand joints Symmetric arthritis Rheumatoid nodules Serum Rheumatoid factor Typical radiographic changes-narrowing of joint space, loss of articular cartilage 4 of the above criteria
RA-Diagnosis
Rheumatoid factor- present in most but not all patients
Analysis of synovial fluid- confirms the presence of neutrophils- inflammatory picture
If RF comes back negative what are the usual other causes of symptoms
Ankylosing spondylitis
Reiter’s syndrome
Psoriatic arthritis
Enteropathic arthritis
Pathogenesis of gout
Deficiency of the enzymes involved in purine metabolism –> uric acid build up
Clinical Features of Gout
Acute arthritis
Chronic arthritis
Tophi in various sites (masses of urate)
Gouty nephropathy
What is Pyogenic osteomyelitis
Systemic illness-fever
Marked pain over the affected region
Test features of Pyogenic Osteomyelitis
X-ray focus of bone destruction surrounded by zone of sclerosis
Blood cultures are positive
Biopsy- if needed shows sheets of neutrophils
How is pyogenic osteomyelitis caused?
Caused by bacteria
Hematogenous spread
Extension from a contiguous site
Direct implantation
Bacteria causing infective arthritis
Bacterial-Staphylococcus, Streptococcus, Gonococcus, Mycobacteria
Features of infective arthritis
Acutely painful and swollen joints with restricted movements
Fever, leucocytosis and elevated ESR,
Predisposing conditions-trauma, IV drug abuse, debilitating illness
Clinical Features of osteoporosis
Vertebral factures
Kyphosis
Scoliosis
Causes of secondary osteoperosis
Endocrine disorders-Hyperparathyroidism,Type1 diabetes
Neoplasia-Multiple myeloma
Malnutrition
Causes of secondary osteoperosis
Age post menopause
What is pagets disease
Osteoclast dysfunction
What causes pagets disease?
Paramyxovirus infection
What is a histological feature of pagets disease?
Histological hallmark –mosaic pattern
Describe osteoclast dysfunction in pagets disease
Predominant osteoblastic activity
Burnt out osteosclerotic stage
Net effect –gain in bone mass
Newly formed bone is disordered and architecturally unsound
Features of pagets disease
Begins in the 5th decade Males > females Axial skeleton and proximal skeleton most commonly involved Pain most common symptom Chalk stick type fractures-common
Tumours in pagets disease
Giant cell tumour- benign tumour
Malignant-Osteosarcoma, chondrosarcoma, malignant fibrous histiocytoma
What is osteomalacia
Decreased bone density- too little bone-osteopenia
Pathogensis of osteomalacia
Defects in matrix mineralization
Related to lack of Vit D
Are skeletal deformities seen in osetomalaica
no
Explain the effects of Hyperparathyroidism
Excessive secretion of Parathormone
Increases bone resorption and calcium mobilisation from the skeleton
Increases renal tubular reabsorption and retention of calcium
Net effect-Hypercalecemia
Osteitis fibrosa cystica-loss of bone mineral with osteoporosis
What is Renal Osteodystrophy
Skeletal changes of chronic renal disease Increased osteoclastic bone resorption Delayed matrix mineralization Osteosclerosis Growth retardation Osteoporosis
