Diseases of MSK 1

Question 1

Features of Osteoarthritis

Answer 1

Erosion of articular cartilage
Bony spurs form
Aging phenomenon

Question 2

Is Osteoarthritis common?

Answer 2

Commonest type of joint disease

Question 3

What is secondary OA?

Answer 3

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

Question 4

OA Pathogensis

Answer 4

Deterioration of cartilage
As the cartilage is worn away-bone forms spurs and fluid filled cysts
Results in pain and limitation of movements

Question 5

Cellular basis of OA

Answer 5

Chondrocytes–> IL1 –> Prostaglandin –>s  lytic enzymes  Matrix breakdown

Question 6

Causes of primary OA

Answer 6

Abnormal stresses in weight bearing joints

Question 7

Features of primary OA

Answer 7

Affects fingers, knees and cervical and lumbar spines

Involvement of fingers- Herberden’s or Bouchard’s nodes

Question 8

Features of RA

Answer 8

Chronic
Producing a non suppurative synovitis- (destruction of articular cartilage and ankylosis of joints)
Also affects skin, muscles, heart, lungs and blood vessels

Question 9

Pathogenesis of RA

Answer 9

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

Question 10

Genetic and viral causes for RA

Answer 10

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

Question 11

Criteria for RA diagnosis

Answer 11

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

Question 12

RA-Diagnosis

Answer 12

Rheumatoid factor- present in most but not all patients

Analysis of synovial fluid- confirms the presence of neutrophils- inflammatory picture

Question 13

If RF comes back negative what are the usual other causes of symptoms

Answer 13

Ankylosing spondylitis
Reiter’s syndrome
Psoriatic arthritis
Enteropathic arthritis

Question 14

Pathogenesis of gout

Answer 14

Deficiency of the enzymes involved in purine metabolism –> uric acid build up

Question 15

Clinical Features of Gout

Answer 15

Acute arthritis
Chronic arthritis
Tophi in various sites (masses of urate)
Gouty nephropathy

Question 16

What is Pyogenic osteomyelitis

Answer 16

Systemic illness-fever

Marked pain over the affected region

Question 17

Test features of Pyogenic Osteomyelitis

Answer 17

X-ray focus of bone destruction surrounded by zone of sclerosis
Blood cultures are positive
Biopsy- if needed shows sheets of neutrophils

Question 18

How is pyogenic osteomyelitis caused?

Answer 18

Caused by bacteria
Hematogenous spread
Extension from a contiguous site
Direct implantation

Question 19

Bacteria causing infective arthritis

Answer 19

Bacterial-Staphylococcus, Streptococcus, Gonococcus, Mycobacteria

Question 20

Features of infective arthritis

Answer 20

Acutely painful and swollen joints with restricted movements
Fever, leucocytosis and elevated ESR,
Predisposing conditions-trauma, IV drug abuse, debilitating illness

Question 21

Clinical Features of osteoporosis

Answer 21

Vertebral factures
Kyphosis
Scoliosis

Question 22

Causes of secondary osteoperosis

Answer 22

Endocrine disorders-Hyperparathyroidism,Type1 diabetes
Neoplasia-Multiple myeloma
Malnutrition

Question 23

Causes of secondary osteoperosis

Answer 23

Age post menopause

Question 24

What is pagets disease

Answer 24

Osteoclast dysfunction

Question 25

What causes pagets disease?

Answer 25

Paramyxovirus infection

Question 26

What is a histological feature of pagets disease?

Answer 26

Histological hallmark –mosaic pattern

Question 27

Describe osteoclast dysfunction in pagets disease

Answer 27

Predominant osteoblastic activity
Burnt out osteosclerotic stage
Net effect –gain in bone mass
Newly formed bone is disordered and architecturally unsound

Question 28

Features of pagets disease

Answer 28

Begins in the 5th decade
Males > females
Axial skeleton and proximal skeleton most commonly involved
Pain most common symptom
Chalk stick type fractures-common

Question 29

Tumours in pagets disease

Answer 29

Giant cell tumour- benign tumour

Malignant-Osteosarcoma, chondrosarcoma, malignant fibrous histiocytoma

Question 30

What is osteomalacia

Answer 30

Decreased bone density- too little bone-osteopenia

Question 31

Pathogensis of osteomalacia

Answer 31

Defects in matrix mineralization

Related to lack of Vit D

Question 32

Are skeletal deformities seen in osetomalaica

Answer 32

no

Question 33

Explain the effects of Hyperparathyroidism

Answer 33

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

Question 34

What is Renal Osteodystrophy

Answer 34

Skeletal  changes of chronic renal disease
Increased osteoclastic bone resorption
Delayed matrix mineralization
Osteosclerosis
Growth retardation
Osteoporosis