Bone and Joint Pathology Flashcards
Describe osteogenesis imperfecta
Disorder of type 1 collagen resulting in abnormal bone formation and mineralisation. Leads to fractures and progressive deformity (A.K.A. Brittle bone disease)
List the pathological features of OA
- Breakdown and loss of articular cartilage
- Loss of joint space
- Reparative bone response
- Capsular fibrosis
List the radiological features of OA
- Loss of joint space
- Osteophyte formation
- Juxta-articular sclerosis
- Subchondral cysts
What happens to cartilage composition with ageing
Reduced proteoglycans leads to reduced water-binding capacity resulting in a thinner, stiffer cartilage
Where is the most common site of initial RA presentation
Foot
What part of the joint does RA affect
Synovial membrane
What gene is associated with RA
HLA-DR4
What does Rheumatoid factor antibody target
Fc portion of autologous IgG
List the radiological features of RA
- Loss of joint space
- Periarticular erosions
- Joint-line thickening
- Juxta-articular osteoporosis
- No osteophytes
Where does Gout typically effect
Metatarsophalangeal joint of the great toe (>50% of cases)
What causes gout
Crystallisation of monosodium urate in the joint
What causes secondary gout
- Medications (thiazides)
- Myeloproliferative/Lymphoproliferative disorders
- Renal failure
Describe gout crystals
Negatively birefringent needle-shaped crystals
List the radiological features of gout
- Punched-out erosions that start near joint margins with classic overhanging sclerotic margin
- Cartilage destruction can cause joint space narrowing in the long-term and is rare
Describe osteochondritis dissecans
Disease where bone under the articular cartilage dies due to lack of blood flow
What are the clinical features of osteochondritis dissecans
- Pain worse with activity
- Swelling and joint effusions
- Loose bodies/locking/giving way of the joint
Define Osteoporosis
- Increased porosity of bone leading to decreased bone density of normally mineralised bone matrix
- Bone density >2.5 SD below normal range for young adults
When is peak bone mass reached
25-30
What common drug can cause osteoporosis
Heparin
List the risk factors for osteoporosis
- Reduced physical activity
- Smoking and alcohol
- Low weight
- Early menopause
- Genetic
In what conditions are DEXA scans not required to diagnose osteoporosis and treatment should be commenced straight away
NOF fractures
What is the treatment of osteoporosis
- Calcium and vitamin D supplementation
- Alendronate (1st-line)
What can be used as an alternative to bisphosphonates in osteoporosis in those intolerant
Strontium ranelate and raloxifene
Describe osteomalacia (Rickets in children)
Deranged vitamin D absorption/metabolism leading to the impaired mineralisation of bone (osteoid)