CP10-3 Osteoarticular Pathology Flashcards
How is haemopoietic precursors related to age?
Haematopoeitic precursors are inversely proportional to age e.g. 10 year old you have haemopoietic precursors make up 90% of their bone marrow
How does the role of osteoblasts and osteoclasts differ?
Osteoclasts remove old bone and osteoblasts produce new bone
what are the main components of bone?
Proteins and calcium deposits
What percentage of bone proteins are type 1 collagen?
90%
What are the main proteins found in bone?
Type 1 collagen
Cell adhesion proteins
Calcium-binding proteins
Enzymes
Growth factors
Cytokines
Proteins concentrated from serum e.g. IGF
how are osteoblasts and osteoclasts affected by calcitonin and PTH?
Calcitonin causes osteoblasts to produce bone
Parathyroid hormone causes osteoclasts to break down old bone
What are 8 causes of bone disease?
- Defects in nuclear proteins and transcriptase factors e.g. polydactyl
What bone disease is caused by defects in hormones and signal transduction mechanisms?
Dwarfism (achondroplasia and thanatophoria)
What bone diseases are associated with defects in extracellular structural proteins?
Osteogenesis imperfecta with blue sclera
What mutations are associated with defects in extracellular structural proteins of bone?
Mutations in genes which code for alpha-1 and alpha-2 chains of collagen
Mutations of collagen 2, 10 and 11
What bone diseases are associated with defects in folding and degradation of macromolecules?
Mucopolysaccharidosis
Decrease in enzymes which degrade dermatan, heparan and keratan
Cartilage disorders causing short malformed chest wall bones
What is mucopolysaccharidosis?
A lysosome storage disease
What are bone diseases associated with defects in metabolic pathways?
Osteopetrosis
Carbonic a hydrate deficiency
Decreased osteoclasts resorption
What are examples of bone diseases associated with decreases bone mass?
Osteoporosis
What is osteoporosis?
When bone mass peaks in early adulthood and bone loss is accelerated.
What increases risk of developing osteoporosis?
Age
Physical activity
Estrogen withdrawl e.g. menopause
Nutrition
Genetics
What is an example of a bone disease associated with osteoclasts dysfunction?
Paget disease aka osteitis deformans
What are the three phases of Paget’s disease?
1) increased osteoclasts resorption
2) increased hectic bone formation by osteoblasts
3) osteosclerosis
What levels are elevated in patients with Paget’s disease?
Alkaline-phosphatase
Urine hydroxyproline
What are examples of bone diseases associated with abnormal mineral homeostasis?
Rikcetts and osteomalacia
Osteitis fibrosis cystica aka von Recklinghausen’s disease or brown’s tumour due to hyperparathyroidism
Renal osteodystrophy
What causes ricketts and osteo malacia?
Vitamin D deficiency
How does hyperparathyroidism affect the bone?
Causes brown’s tumour
Can cause osteitis fibrosis cystica aka Recklinghausen’s disease
What is renal osteodystrophy?
Any bone disorder which occurs due to chronic renal disease
What are examples of renal osteodystrophy?
Phosphate retention
Hypophosphataemia
Hypocalcaemia
Increased PTH
Increased osteoclasts
Metabolic acidosis as it releases hydroxyapatites from the bone matrix
What words are used to describe fractures?
Complete vs incomplete
Scolded vs open
Communited vs non-communited (splintered)
Displaced vs non-displaced
Pathogenic
Stress fracture
What are the three phases of fracture?
1) Haematoma in minutes to days by PDGF, TGF-beta, FGF
2) soft callus/pro-callus within a week
3) hard callus/bony callus after several weeks
What are 2 complications of fractures?
Pseudarthrosis
Infection especially in open (communicating) fractures
What causes osteonecrosis?
ISCHAEMIA due to:
Trauma
Steroids
Thrombus/embolism
Vessel injury e.g. due to radiation
Increased intra-osseous pressure causing vascular compression
Venous hypertension
What are other names of osteonecrosis?
Avascular necrosis
Aseptic necrosis
What causes osteomyelitis?
Pyogenic causes like staph, e.coli, pseudomonas and klebsiella which are introduced via hematogenous, contiguous or direct implantation.
TB
Syphilis
What is osteomyelitis?
Destruction of bone via inflammation usually due to infection
What occurs in bone in acute osteomyelitis?
An abscess of bone
What are complications of osteomyelitis?
Subperiosteal abscesses
Draining sinus
Joint involvement
What is sequestrum?
Dead bone
What is involucrum?
New bone
What is TB of spine known as?
Potts disease
How can syphilis affect bone?
Causes tertiary sabre shins
What are some examples of benign bone tumours?
Osteoma
Osteoid osteoma
Osteoblastoma
What is an example of a malignant bone tumour?
Osteosarcoma aka osteogenic sarcoma
What are osteomas?
Solitary, benign tumours from subperiosteal or endosteal surfaces usually in the skull or face. They are hard to distinguish from reactive bone. Common in middle aged people.
What are osteoid osteomas?
Painful bone tumours, common in teens and young adults, especially men, affecting the appendicular skeleton inducing a marked bony reaction. They have a nidus and respond to aspirin.
What are osteoblastomas?
Benign tumours of the axial skeleton (the spine) which have no nidus nor bony reaction. They are not relieved by aspirin.
what sign can be seen in osteoblastomas of long bones on x-rays?
Colman’s triangle
What are examples of bone tumours associated with cartilage?
Osteochondroma
Chondroma
Chondroblastoma
Chondromyxoid fibroma
Chondrosarcoma
What are osteochondromas?
Common tumours of the cartilage and bone usually found in the pelvis, scapula and ribs. There are often multiple as it is a hereditary syndrome which predominantly affects men more than women.
What are chondromas?
Tumours of pure hyaline cartilage. Can be chondromas or en-chondromas. If hemangiomas are present, the patient has maffucci syndrome.
What is a patient diagnosed with if they have multiple enchondromas?
Ollier’s disease
What are chonroblastomas?
Rare tumours found in teenagers, males more than females, usually at the knees at the epiphyses. These tumours have much less matrix than chondromas.
What are chondromyxoid fibromas?
The rarest bone tumour affecting cartilage affecting teenage men primarily and have a myoxid concept with atypia.
What are chondrosarcomas?
Malignant Intramedullay or juxtacortical tumours which upon histology are seen to have hyaline and myoxid, appear clear, de-differentiated and mesenchymal.
What are the different types of chondrosarcomas?
Intramedullay
Juxtacortical
What are examples of bone fibrous tumours?
Fibrous cortical defect/non-ossifying fibroma
Fibrous dysplasia
Fibrosarcoma/malignant fibrous histiocytoma
How can you differentiate between benign and malignant bone tumours?
If end in oma = benign
If ends sarcoma = malignant
What is a fibrous cortical defect?
A common tumour in children under 2 that is less than 1 cm in diameter
If more than 5-6 cm classed as a non-ossifying fibroma
What are the three types of fibrous dysplasia (bengin)?
Single bone
Poly-ostoitic
Poly-ostotic with café-au-lait and endocrine disorders especially precocious puberty
What is fibrosarcoma aka MFH?
A metaphyses of long bones and/or pelvic flat bones. They are lyric and can cause pathological fractures and sarcomatous metastases.
What are some miscellaneous tumours of bone?
Ewing sarcoma/PNET
Giant cell tumours
Metastases
What is Ewing’s sarcoma aka PNET?
A small round tumour in the neuroendocrine system which arises in the medullary cavity of bone. They are caused by an identical chromosome translocation and can look like lymphomas.
What is a giant cell tumour?
A common benign bone tumour usually in the metaphysis or epiphysis of the femur or tibia. Usually occurs in adults between 20-40.
What common tumours metastasise to bone ?
Prostate
Breast
Renal
Thyroid
What diseases affect the joint?
Arthritis
Tumours
What is osteoarthritis?
A progressive erosion of articular cartilage resulting in pain and limitation of movement due to eburnation, joint mice and osteophytes in the joint.
What is rheumatoid arthritis?
A chronic systemic inflammatory autoimmune disorder affecting multiple tissues and organs including the joints primarily. It causes unsuppurative proliferative and inflammatory synovitis which often progresses into destruction of the articular cartilage and ankylosis of the joints.
What cells form the synovial intima?
Fibroblasts -hyaluronin and lubricin
Macrophages
What joints are affected by rheumatoid arthritis?
Hands, wrists and elbows
What are the symptoms and signs of rheumatoid arthritis?
What is juvenile rheumatoid arthritis?
rheumatoid arthritis with onset <16 affecting large joints. Often positive for antinuclear antibodies.
What are types of seronegative arthiritis?
What is infectious arthritis?
What commonly causes infectious arthritis?
What is gout?
What increases risk of developing gout?
Age
Genetic predisposition - —linked abnormalities of HGPRT
Heavy alcohol consumption
Obesity
Drugs e.g. thiazides
Lead toxicity
What are complications of gout?
Tophaceous arthritis
Gouty nephropathy
What is associated with gout?
Atherosclerosis
Hypertension
What is pseudo-gout?
What are examples of benign joint tumours?
Ganglion/synovial cysts
Giant cell tumour of tendon sheath
What is an example of a malignant joint tumour?
Synovial sarcoma
What are causes of soft tissue tumours?
Mostly unknown but associate with:
Radiation
Chemical burns
Thermal burns
Trauma
Viruses
Genetics
How are soft tissue tumours characterised?
All spindly
Can be deep in Desmond or superficial on skin
By counting mitoses
What are some tumours of fat?
Lipoma
Liposarcoma
What are examples of fibrous tissue tumours?
Nodular fasciitis
Fibromatoses
Fibrosarcomas
What is myositis ossificans?
What is fibrohistiocytic tumour?
What are examples of skeletal muscle tumours?
rhabdomyoma
rhabdomyosarcoma
What are examples of smooth muscle tumours?
leiomyoma
leiomyosarcoma
What are examples of vascular tumours?
What are examples of peripheral nerve tumours?
What are some miscellaneous soft tissue tumours?
Synovial sarcoma
Alveolar soft part sarcoma
Epitheliod sarcoma
