Musculo-Skeletal Pathology Non-Neoplastic 02/10/18 Flashcards
What are the 4 non-neoplastic causes of MSK disease?
Connective tissue diseases
Metabolic diseases
Fractures
Degenerative Disease
What are the basics of the 4 Hypersensitivity reactions?
1 - Immediate IgE
2 - Antibody mediated
3 - Immune complex mediated
4 - Delayed/Cell mediated
Are connective tissue diseases autoimmune?
yes
The presence of what characterises a connective tissue disease?
Autoantibodies
What percentage of the population have a connective tissue disease?
1-2%
Give 2 conditions and their autoantibodies
Rhematoid arthritis - rheumatoid factor
Lupus - often structural parts of DNA
Scleroderma - Anti-centromere
Dermatomyositis - Anti Jo
What is Rheumatoid arthritis?
Inflammation of the joints
What autoantibodies are present in reumatoid arthritis?
Rheumatoid factor
Autoantibody agains Fc IgG
Can rheumatoid arthritis be systemic?
Yes
What is formed in the acute phase of RA?
Pannus
Inflammatory granulation tissue at the edges and over the articular surfaces of joints
What happens to the cartilage in RA?
It is destroyed
What occurs in the chronic phase of RA?
Fibrosis
Deformity
What kind of condition is SLE?
Prototypic systemic auto-immune condition
What are the autoantibodies directed at in SLE?
DNA
ANA is +ve in what percentage of lupus patients?
95%
What are some other antibodies found in SLE?
Anti double stranded DNA \+ve anti-sm RNP SS-A SS-B
What cells are present in chronic inflammation?
Lymphocytes and plasma cells
What are the acute histological signs in inflammatory conditions?
Oedema
Fibrin
Reactive features in synovial cells
What are 3 metabolic diseases?
Pagets
Osteomalacia
Crystal arthropathies
What is an example of a crystal arthropathy?
Gout
What is the end product of purine synthesis?
Uric acid
What 2 DNA bases are purine based?
Adenine and Guanine
When is urate formed?
DNA replication
What are the two reasons for Hyperuricaemia?
Increased production of Uric acid
Reduced excretion
Why does increased production of uric acid occur?
Usually idiopathic
HGPRT deficiency
Increased cell turnover - Psoriasis, Leukamia
What is a reason for reduced excretion of uric acid?
Drugs - Thiazide diuretics
What are the clinical manifestations of hyperuricaemia?
Precipitation of crystals Usually in joints Elicit acute inflammatory reaction Gouty tophus Renal disease
What are the pathological findings of hyperuricaemia?
Long thin needle shaped crystals
Amorphous eosinophillic debris and inflammation
What can Calcium pyrophosphate deposition cause?
Common crystal arthropathy
Psuedogout or chondrocalcinosis
What are the symptoms of pseudogout?
Usually none
May have joint pain
What is seen on investigations for psuedogout?
Large Rhombus shaped crystals
What is paget’s disease?
Abnormality of bone turnover
Increased osteoclastic activity but not normally structured
What causes Pagets disease?
Not sure
Genetic?
Viral infection
What are the three stages of Paget’s disease?
Osteolytic
Mixed
Burnt Out
Are the reversal lines normal in pagets?
No they are mosaic like
When can pagets cause pain?
Microfracture or nerve compression
What does pagets do to bones?
Enlargement and abnormal shape Leontiasis Ossea Platybasia Sabre tibia
What is the malignancy that pagets can cause?
Osteosarcoma
What metabolic affects can pagets have?
Heat
Warm skin
AV shunt
Cardiac failure
What is osteomalacia?
Abnormal Vitamin D metabolism
What is osteomalacia related to?
Sun exposure
What does osteomalacia cause?
Rickets Bowed legs Square heads Pigeon chest Rickety rosary
What is a pathological fracture?
Where the fracture is outkeeping with the level of trauma
E.g. Osteoporitic fractures, Tumours
What are the initial phases of trauma?
Haematoma
Influx of inflammatory cells
Cytokine release
After a week - callus, organised haematoma, early remodelling at bone ends
What occurs during weeks 2-3 of bone repair?
Maximum girth of callus
Woven bone deposited perpendicular to cortical bone
Cartilage deposition at fracture site which undergoes endoochondral ossification
Bridging with bony callus
What causes bony lesions?
Malignant proliferation of plasma cells
What is the difference between osteosclerotic and osteolytic lesions?
Sclerotic - appear as areas of opacity (prostate)
Lytic - Bone is resorbed and appear as radiolucent
What is Avascular necrosis?
Bone infarction
What causes avascular necrosis?
Alcohol
Trauma
Steroids
What shape is the infarct in avascular necrosis?
Wedge shaped
Subcortical
What is an example of a degenerative disease?
Osteoarthritis
What are the stages involved in joint changes?
Early - small cracks in cartilage Fibrillation Cartilage is worn away Bone on Bone Surface becomes polished - eburnation Cortical bone thickens greatly to cope with load Leakage of synovial fluid forming small cysts Rapid bone remodelling Mistakes are made and osteophytes form
What is eburnation?
Subchondral sclerosis
What is a subchondral cyst?
Synovial fluid accumulation
What is an osteophyte?
Disorganised bone remodelling
