Soft Tissue, Bone & Joint Pathology Flashcards
How many bones are within the skeletal system?
What kind of conditions affect it?
skeletal system is composed of 206 bones interconnected by a variety of joints
affected by circulatory, inflammatory, neoplastic, congenital and metabolic disorders
What is meant by arthritides?
pain and stiffness of a joint and inflammation of the joint
this is not a single disease, but hundreds of diseases that cause pain and stiffness of the musculoskeletal system
What are the 2 different types of arthritis?
acute arthritis:
- pain, heat, redness and swelling in a joint
chronic arthritis:
- e.g. osteoarthritis & rheumatoid arthritis
What is osteoarthritis?
a degenerative joint disease that involves progressive erosion of articular cartilage
this results in the formation of bony spurs and cysts at the margins of joints
What is the cause of osteoarthritis?
Where does it tend to be seen in men and women?
- it is an aging phenomenon with no apparent initiating cause
- associated with underlying systemic diseases such as diabetes and marked obesity
- affects the knees and hands in women and the hip in men
What is meant by secondary osteoarthritis and who tends to be affected?
secondary OA is caused by another disease or condition
it is seen in the knee of basketball players and elbow of baseball players
What is the difference between primary and secondary osteoarthritis?
primary OA:
- also known as idiopathic
- affects joints of one site with no known cause
secondary OA:
- affects a joint at one site and is due to some external or internal injury or disease
What are some common causes of secondary osteoarthritis?
- obesity
- repeated trauma or surgery to joint structures
- abnormal joints at birth (congenital abnormalities)
- gout
- rheumatoid arthritis
- diabetes
- other hormone disorders
What is involved in the pathogenesis of osteoarthritis?
deterioration or loss of cartilage that acts as a protective cushion in between the bones
as the cartilage is worn away, the bone forms spurs
fluid-filled cysts form in the marrow (subchondral cysts)
this results in pain and limitation of movements
What cells are involved in the pathogenesis of osteoarthritis?
- chondrocytes produce interleukin-1 which initiates matrix breakdown
- prostaglandin derivatives induce the release of lytic enzymes, which prevents matrix synthesis
Which joints tend to be affected by primary osteoarthritis?
How can it be recognised on the fingers?
- caused by abnormal stresses in weight-bearing joints
- affects fingers, knees and cervical and lumbar spines
- involvement of the fingers sees Herberden’s or Bouchard’s nodes
What is rheumatoid arthritis and what structures are implicated in this condition?
a chronic systemic disorder which principally affects the joints
it produces a non-suppurative proliferative synovitis leading to destruction of articular cartilage and ankylosis of joints
it also affects the skin, muscles, heart, lungs and blood vessels
Are women or men more likely to be affected by rheumatoid arthritis?
women are 3-5 times more likely to be affected than men
What is ankylosis of the joints?
stiffness of a joint due to abnormal adhesion and rigidity of the bones of the joint
this may be the result of injury or disease
What is shown here?
a normal joint with thin synovium
What is the first stage in development of rheumatoid arthritis?
polypoid fibrovascular thickening of the synovium with synoviocyte hyperplasia
this produces a pannus that is eroding into the articular cartilage
What is the second stage in the development of osteoarthritis?
continued growth of the pannus and erosion of the cartilage with penetration into the subchondral bone and cyst formation
What is the third stage in the development of rheumatoid arthritis?
filling of the joint space with pannus, producing ankylosis of the joint space
this is rheumatoid arthritis
What are the clinical features of rheumatoid arthritis?
How fast is disease course?
Which joints are frequently affected?
- starts with malaise, fatigue and generalised musculoskeletal pain
- involved joints are swollen, warm, painful and stiff in the morning or after activity
- slow or rapid disease course which fluctuates over 4-5 years
- small joints of the hands and feet are frequently affected, producing a deformed joint
What is involved in the pathogenesis of rheumatoid arthritis?
- genetic susceptibility 65-80% - HLA DR4 & DR1 or both
- primary exogenous arthritogen is EBV (or other viruses), Borrelia
- autoimmune reaction within the synovial membranes involves CD4+ T-cells
- mediators of joint damage are cytokines IL 1-6 and TNF-a and TNF-b
What are the criteria for the diagnosis of rheumatoid arthritis?
- morning stiffness
- arthritis in 3 or more joint areas
- arthritis of hand joints
- symmetric arthritis
- rheumatoid nodules
- serum rheumatoid factor
need 4 of the above criteria for diagnosis
also look for typical radiographic changes of narrowing of the joint space and loss of articular cartilage
What tests are performed in the diagnosis of rheumatoid arthritis?
- rheumatoid factor is present in most but not all patients and is less specific
- analysis of synovial fluid to confirm the presence of neutrophils (inflammatory picture)
What other organs are involved in rheumatoid arthritis?
- skin - rheumatoid nodules are the commonest cutaenous manifestation in areas of pressure
- lungs, spleen, heart, other viscera
What feature of rheumatoid arthritis is visible here?
palisaded granulomata
What is meant by sero-negative arthritides?
What are the 4 main conditions?
rheumatoid factor is usually negative in these conditions
- ankylosing spondylitis
- Reiter’s syndrome
- psoriatic arthritis
- enteropathic arthritis
What is gout?
What causes it?
it is the end-point of a group of disorders producing hyperuricemia
uric acid is the end product of purine metabolism
in gout, there is a deficiency of the enzymes involved in this process
What are the clinical features of gout?
- acute arthritis
- chronic arthritis
- tophi in various sites
- gouty nephropathy
How does someone with gout usually present?
What kind of attacks would they describe?
transient attacks of acute arthritis
crystallisation of urates within and about the joints leads to chronic gouty arthritis
and deposition of masses of urates in joints and other sites, producing tophi
What is shown here?
gout
What is pyogenic osteomyelitis?
What symptoms does it produce?
an inflammation of bone caused by an infecting organism
(most commonly Staphylococcus aureus)
it produces systemic illness with fever, malaise, chills and marked pain over the affected region
What tests are performed for pyogenic osteomyelitis and what would the findings be?
- X-ray - lytic focus of bone destruction surrounded by zone of sclerosis
- blood cultures are positive
- biopsy shows sheets of neutrophils
What is pyogenic osteomyelitis caused by?
How does this happen?
it is caused by bacteria and can occur via:
- haematogenous spread
- extension from a continguous site
- direct implantation
What is infective arthritis and what causes it?
caused by bacteria:
- staphylococcus
- streptococcus
- gonococcus
- mycobacteria
produces acutely painful and swollen joints with restricted movements
What are the symptoms and signs of infective arthritis?
What predisposing conditions is it associated with?
associated with fever, leucocytosis and elevated ESR
predisposing conditions include trauma, IV drug abuse and debilitating ilness
What is osteoporosis and what are the 2 different types?
an increased porosity of the skeleton and a reduction in bone mass
it can be localised or affect the entire skeleton
it is either primary or secondary
What is the difference between primary and secondary osteoporosis?
primary:
- bone loss that occurs during the normal human aging process
- often occurs in postmenopausal women
secondary:
- bone loss resulting from specific, well-defined clinical disorders
What are the 4 main factors which can influence osteoporosis?
- physical activity
- muscle strength
- diet
- hormonal status
What are the 3 main clinical features of osteoporosis?
- vertebral fractures
- kyphosis
- scoliosis
What tends to cause secondary osteoporosis?
- endocrine disorders - hyperparathyroidism, type 1 diabetes
- neoplasia - multiple myeloma
- malnutrition
What disease results from osteoclast dysfunction?
What causes this?
Paget’s disease
this shows a collage of matrix madness and its histological hallmark is a mosaic pattern
it is caused by paramyxovirus infection
What happens in Paget’s disease?
it is a condition involving cellular remodelling and deformity of one or more bones
affected bones show dysregulated bone remodelling
there is excessive bone breakdown and subsequent disorganised new bone formation
structural changes cause the bone to weaken, which may result in deformity, pain, fracture or arthritis of associated joints
What are the 3 stages in Paget’s disease?
What is the net effect of this condition?
- initial osteolytic stage
- predominant osteoblastic activity
- burnt out osteosclerotic stage
the net effect is a gain in bone mass
the newly formed bone is disordered and architecturally unsound
Who tends to be affected by Paget’s disease?
What is the most common symptom?
- begins in the 5th decade
- affects more males than females
- commonly involves axial skeleton and proximal skeleton
pain is the most common symptom
chalk stick type fractures are common
What is shown here?
paget’s disease
What benign and malignant tumours are seen in Paget’s disease?
benign:
- giant cell tumour
malignant:
- osteosarcoma
- chondrosarcoma
- malignant fibrous histiocytoma
What is osteomalacia?
What causes it?
defects in matrix mineralisation related to a lack of vitamin D
leads to decreased bone density and osteopenia
skeletal deformities are not seen
What is the difference between osteopenia and osteoporosis?
osteopenia is having a lower bone density than the average for your age, but not low enough to be callsed as osteoporosis
osteopenia does not always leads to osteoporosis
What is the definition of osteomalacia?
a disease characterised by the softening of the bones caused by impaired bone metabolism
this is due to inadequate levels of available phosphate, calcium and vitaminD or due to reabsorption of calcium
the impairment of bone metabolism causes inadequate bone mineralisation
What is hyperparathyroidism?
How does it affect metabolism?
excessive secretion of parathyroid hormone
increases bone resorption and calcium mobilisation from the skeleton
increases renal tubular reabsorption and retention of calcium
What is the net effect of hyperparathyroidism?
What can it lead to?
hypercalcaemia
can lead to osteitis fibrosa cystica
this is the loss of bone mineral with osteoporosis
What is renal osteodystrophy?
the skeletal changes involved in chronic renal disease
- increased osteoclastic bone resorption
- delayed matrix mineralisation
- osteosclerosis
- growth retardation
- osteoporosis
What is osteosclerosis?
a disorder characterised by abnormal hardening of bone and an elevation in bone density
What are soft tissue tumours?
What is their origin and what tissues do they arise from?
nonepithelial extraskeletal structures exclusive of supportive tissue of organs and lymphoid / hematopoietic tissue
they are mesodermal in origin
includes fibrous tissue, adipose tissue, skeletal muscle, blood / lymphatic vasculature, peripheral nervous system
What are the most common benign soft tissue tumours and what do they arise from?
- lipomas - fat tissue
- fibromas - fibrous tissue
- leiomyomas - smooth muscle
- haemangiomas - blood vessels
- lymphangiomas - lymphatics
- neuromas - peripheral nerves
What are the malignant soft tissue tumours?
Where do they spread to
Which tumours rarely behave malignantly?
sarcomas
they spread via the blood to the liver, lung, etc.
lymph node involvement is uncommon
congenital tumours rarely behave malignantly, even with aggressive features
What syndromes are associated with soft tissue tumours?
- neurofibromatosis type I - neurofibroma
- gardner syndrome - fibromatosis
- carney syndrome - myxoma, melanotic schwannoma
- turner syndrome - cystic hygroma
What is Gardner’s syndrome?
- also known as familial colorectal polyposis
- it is a subtype of familial adenomatous polyposis (FAP)
- it is an autosomal dominant condition characterised by the presence of multiple polyps in the colon together with tumours outside the colon
What is Carney syndrome?
a rare genetic disorder characterised by multiple benign tumours (multiple neoplasia)
it most often affects the heart, skin and endocrine system
it leads to abnormalities in skin colouring, resulting in a spotty appearance to the skin of affected areas
What is Turner syndrome?
What symptoms is it associated with?
it is a condition affecting only females that results when one of the X chromosomes is missing or partially missing
it causes many problems inlcuding short height, failure of the ovaries to develop and heart defects
What are the different approaches to diagnosis of soft tissue tumours?
- ultrasound guided core biopsy
- wide excision
- cytogenetics - culture of fresh tissue and karyotypic analysis
- molecular genetics - FISH and PCR and RT-PCR
Where do bone tumours arise from?
What are benign ones called?
they arise from bone and cartilage
benign bone tumours are osteomas and osteoblastomas
benign cartilage tumours are chondromas
mixed tumours are osteochondromas
What are malignant bone tumours called?
Where is the commonest site?
osteosarcoma
they affect a young age group and the commonest site is around the knee (60%)
What are other types of bone tumours?
- chondrosarcomas
- Ewing’s sarcoma
- giant cell tumour
Where do metastatic bone tumours tend to spread to?
- thyroid
- prostate
- kidney
- breast
- GI tract
What is systemic lupus erythematosus?
Who is more likely to be affected?
it is a complex multi-system disease that is predominantly cutaneous
it is characterised by the presence of antinuclear antibodies
it shows a female predominance
What are the cutaneous, cardiac, CNS and renal implications of SLE?
cutaneous:
- butterfly rash affecting the bridge of nose and the cheeks
cardiac:
- cardiomegaly
- endocarditis
CNS:
- important cause for morbidity and mortality
- convulsions, hemiplegia
renal:
- affects 45% of patients
- nephrotic syndrome and glomerulonephritis
What is systemic sclerosis?
an autoimmune rheumatic disease characterised by excessive production and accumulation of collagen (fibrosis) in the skin and internal organs and by injuries to small arteries
pathogenesis is complex and poorly understood
What organs are typically involved in systemic sclerosis?
- diffuse - widespread cutaneous lesions
- renal, cardiorespiratory and gastrointestinal tract
- osteoarticular involvement - arthralgia and arthritis
- has a poor prognosis
What is the localised variant of systemic sclerosis characterised by?
- limited cutaneous involvement + oesophageal involvement and SI malabsorption
- CREST syndrome
- calcinosis
- Raynaud’s phenomenon
- oesophageal dysfunction
- sclerodactyly
- telangiectasia
What are the symptoms of polymyalgia rheumatica?
- stiffness
- weakness
- aching and pain in the muscles of the neck, limb girdles and upper limbs
What is polymyalgia rheumatica associated with?
associated with giant cell arteritis
this affects occipital or facial arteries and leads to pyrexia, headache and severe scalp pain
What is the difference between myopathy and myositis?
myopathy:
- muscle disease unrelated to any disorder of innervation or neuromuscular junction
myositis:
- muscle fibres and overlying skin are inflamed and damaged resulting in muscle weakness
what is muscular dystrophy?
a heterogenous group of inherited disorders
progressively severe muscle weakness and wasting that begins in childhood
What is malignant hyperthermia?
an inherited disease
a fast rise in body temperature and severe muscle contraction when the affected person gets general anaesthesia
What happens in rhabdomyolysis?
destruction of skeletal muscle and release of muscle fibre content into the blood
myoglobin is released into the blood stream
it is filtered through the kidney and enters the urine leading to myoglobinurea (brown urine)
What causes rhabdomyolysis?
- trauma, crush injuries
- drugs - cocaine, amphetamine
- extreme temperature
- severe exertion - marathon running
- lengthy surgery
- severe dehydration
- important complication - acute renal failure
What are metabolic myopathies?
- glycogen synthesis and degradation
- disorders of mitochondrial metabolism
What are the symptoms of malignant hyperthermia?
- bleeding
- dark brown urine
- muscle rigidity
- quick rise in body temperature to 105 degree F or higher
- may have family history
- discovered during anaesthesia
