Bone Tumours Flashcards
What are different classifications of fractures?
Complete or Incomplete
Closed (Simple): Clean break with intact soft tissue
Comminuted: Splintered bone with intact soft tissue
Compound: Fracture site communicates with skin surface
What are the stages of fracture repair?
Organisation of haematoma at fracture site (pro-callus)
Formation of fibrocartilaginous callus
Mineralisation of fibrocartilaginous callus
Remodelling of bone along weightbearing lines
What is this?
Fractured bone
What is this?
Repaired fracture
What is this?
Fracture callous - can be mistaken for osteosarcoma
What are factors influencing fracture healing?
Type of fracture
Presence of infection
Pre-existing systemic condition:
- Neoplasm
- Metabolic disorder
- Drugs
- Vitamin deficiency
Pseudoarthrosis may result
What are common sites of osteomyelitis?
Adults:
- Vertebrae
- Jaw (2º to dental abscess)
- Toe (2º to diabetic skin ulcer) (>3mm)
Children:
- Long bones (usually metaphysis)
What are clinical features of osteomyelitis?
General: Malaise, fever, chills, leucocytosis
Local: Pain, swelling and redness
60% positive blood cultures
X-ray: Mixed picture eventually lytic
What are common causative organisms of osteomyelitis?
Almost always bacterial
Rarely fungal
What are routes of infection for osteomyelitis?
Haematogenous (blood borne)
Direct extension
Traumatic (inc surgery)
What are the causative bacterial species in adults with osteomyelitis?
Staph Aureus(90%)
E. Coli
Klebsiella
Salmonella (associated with sickle cell disease)
Psuedomonas (IVDA)
What are the causative bacterial species in neonates with osteomyelitis?
Haemophilus influenzae
Group B Streptococcus
Occasionally enterobacter
What is this?
Core biopsy - Osteomyelitis
What are common X-Ray changes of osteomyelitis?
Usually appear 10 days or so post onset
Mottled rarefaction and lifting of periosteum
>1week: Irregular sub-periosteal new bone formation called involucrum
Later: Irregular lytic destruction (takes 10-14 days)
Some areas of necrotic cortex may become detached called sequestra (takes 3-6 weeks).
What is the Cierny-Mader staging system for osteomyelitis?
Anatomic type:
- Stage 1: Medullary OM
- Stage 2: Superficial OM
- Stage 3: Localised OM
- Stage 4: Diffuse
Physiologic class:
- Host A: Normal
- Host B: Local or systemic compromise
- Host C: Treatment worse than disease
What is the association between TB and osteomyelitis?
Rare cause of OM (3-5% cases of extra-pulmonary TB). Affects immunocompromised patients. More destructive and resistant to control.
Spinal disease (50% cases) may result in psoas abscess and severe skeletal deformity (Pott’s disease).
Systemic amyloidosis may result in protracted cases.
What is the association between of syphillis and osteomyelitis?
Another rare cause of OM (Treponema pallidum)
May be congenital or acquired
Congenital skeletal lesions:
- Osteochondritis
- Osteoperiostitis
- Diaphyseal osteomyelitis
What are late skeletal lesions associated with syphillis?
Non-gummatous periostitis
Gummatous inflammation of bone and joints
Neuropathic joints (Tabes Dorsalis)
Neuropathic shaft fractures
What is Lyme Disease?
Inflammatory arthropathy as part of a complex multisystem illness resulting from tick bite. It is the most prevalent vector bone disease in temperate Northern hemisphere.
What is the organism and tick species causing Lyme Disease?
Organism: Borrelia burgdorferi
Tick Species: Ixodes dammini
What is the epidemiology of Lyme Disease?
Affects both sexes equally.
Onset between May and November
What are the three clinical stages of Lyme Disease?
Stage 1: Early localised
Characterised by rash (90%) usually within 7-10 days and between 1 & 50cm diameter. Often thigh, groin, axilla (earlobe in children).
Stage 2: Early Disseminated
Effects many organs, musculoskeletal, heart, nervous system.
Stage 3: Late, persistent
Dominated by arthritis.
What is the management of Lyme Disease?
Treatment is based on prevention.
Vaccines are available.
Antibiotics for proven disease.
No effective prophylaxis.
Diagnosis is clinical. No specific histological features.
What is osteoarthritis?
Degenerative joint disease
What is primary and secondary osteoarthritis?
Primary: Age related
Secondary: Any age, previously damaged or congenitally abnormal joint.
What is this?
Osteoarthritis - femoral head
What is this?
Femoral head avascular necrosis
What is the aetiology of osteoarthritis?
Biomechanical factors
Biochemical factors
Ageing
Genetic
What is the result of osteoarthritis?
Cartilage degeneration
Fissuring
Abnormal matrix calcification
Osteophytes
Where are common sites for osteoarthritis?
Main sites vertebrae hips and knees
DIPJ/PIPJ of the hand
Carpometacarpal and metatarsophalangeal joints
What is this?
Synovium in OA
What is rheumatoid arthritis?
Severe chronic relapsing synovitis
Unpredictable course
What is the epidemiology of rheumatoid arthritis?
Incidence 1% world population
(Europeans 0.3-1%; Asians 0.1-1.5%; Native Americans 5-7%)
3F:1M
Age 30-40y
What is the aetiology of rheumatoid arthritis?
Aetiology: Most likely autoimmune
80% patients RF +ve
RF mostly IgM
RF forms immunocomplexes with IgG
These circulating immune complexes may underlie associated extra-articular disease.
What are risk factors for rheumatoid arthritis?
Genetic predisposition (risk alleles TNFA1P3, STAT4)
Increased incidence amongst first degree relatives
Associated with HLA DR4 & DR1 (Chr 6p21)
What are clinical features of rheumatoid arthritis?
Mild anaemia
Raised ESR
RF+ve(80%)
+/- Rheumatoid nodules (25%)
Can be multisystem disease
What are characteristic sites for rheumatoid arthritis?
Radial deviation of wrist
Ulnar deviation of fingers
‘Swan neck’ & ‘Boutonniere’ deformity of fingers
‘Z’ shaped thumb
What are differentiating features between RhA and OA?
RhA:
- Symmetrical
- Small joints, hands and feet, sparing DIPJ
- Wrists elbows ankles and knees
What is the histology of RhA?
Proliferative synovitis with:
- Thickening of synovial membranes (villous)
- Hyperplasia of surface synoviocytes
- Intense inflammatory cell infiltrate
- Fibrin deposition and necrosis
Pannus is the exuberant inflamed synovium the articular surface
What is this?
Rheumatoid Arthritis
What is the inflammatory features of RhA?
Proliferative synovitis
Associated upregulation of CFos /AP1 and osteoporosis, IL1β and TNFα
Intense inflammatory cell infiltrate
Production of IL6, TNFα and CRP by liver
IL1 & IL6 induce MMPs – joint destruction
Circadian rhythm of host disturbed
What are these?
Grimley-Sokoloff cells
What are the 5 stages of RhA?
- Unknown antigen reaches synovial membrane
- T–cell proliferation associated with increased; B-cells and angiogenesis
- Chronic inflammation with inflammatory cytokines
- Pannus formation
- Cartilage and bone destruction
What is this?
Gout
What is gout?
Affects any joint but great toe in 90%
Usually limited to lower extremities
Precipitate of needle shaped crystals into joint
Tophus is the pathognomic lesion
What is this?
Gouty tophus
What is this?
Urate crystals
What are features of pseudogout?
Calcium pyrophosphate: Mainly knees
Calcium phosphates (hydroxyapatite): Knees and shoulders
Usual age > 50y
What is this?
Ca pyrophosphate crystals
What is this?
Calcium pyrophosphate crystals
What is this?
Calcium pyrophosphate crystals
What are subsets of pseudogout?
Sporadic: 8% pts <75; 22%>85 ?F>M
Metabolic: Haemochromatosis, primary HPT, hypoMg; low PO4
Hereditary (autosomal dominant) ANKH mutn: Transmembrane glygoprotein. Chr 8q, 5p, younger age 18% OA knee; 10% hip)
Traumatic
