MSK Flashcards
What causes osteoarthritis?
Combination of genetic factors, overuse and injury
What are the risk factors for osteroarthritis?
Obestiy, Age, occupation, trauma, female, family history
What are the 4 key X-ray changes in osteoarthritis?
LOSS: Loss of joint space Osteophytes Subchondral sclerosis Subchondral cysts
What is subchondral sclerosis?
Increased density of the bone along the joint line
What are subchondral cysts?
Fluid-filled holes in the bone.
What is the subchondral bone?
Layer of bone just below the cartilage in a joint (chondral= cartilage)
What are the two types of bone structure?
Macro and micro
What are the types of macro bone structure?
Cortical
Trabecular
What is the structure of cortical bone and where is it found?
Compact, dense. Only spaces are for cells and blood vessels.
Typically found in outer layer of long bones.
80% of bone mass
What is the structure of trabecular bone and where is it found?
Cancellous (spongy) with network of struts (trabeculae). Cells are in the trabeculae and blood vessels in holes.
Found in end of long bones.
What are the different micro bone structures?
Woven bone
Lamellar bone
What is woven bone and where is it found?
Made quickly, disorganised with no clear structure.
Found in places with rapid bone growth, replacement or high bone turnover.
What happens to woven bone after completion of growth?
It turns into lamellar bone
What is lamellar bone and how does it form?
Organised bone with a layered structure. Made slowly from the remodelling of immature woven bone.
What are the different types of bone?
Long bones Short bones Flat bones Irregular bones Sesamoid bones
What are the main bone cells?
Osteoclast
Osteoblast
Osteocyte
Bone lining cell
What is the function of osteoblasts?
Form bone:
Produce type 1 collagen and mineralise the extracellular matrix
What is the function of osteoblasts?
Resorb bone:
Dissolve the mineralised matrix (acid) and breakdown collagen (enzymes)
How are bones made to be the right shape?
Modelling and remodelling: gross shape made, bone added and taken away then all bone is replaced.
What are osteocytes?
Mature bone cells involved in the maintenance of bone (osteoblast enclosed in the matrix)
What is the composition of bone?
- 50-70% mineral (Hydroxyapatite)
- 20-40% organic matrix: Type one collagen (90%), non-collagenous proteins (10%)
- 5-10% water.
What is the purpose of mineral in bone and what is the purpose of the collagen?
Mineral provides stiffness
Collagen provides elasticity.
What is the function of joints?
- Allow movement in 3 dimensions
- Bear weight
- Transfer load evenly
What are the different types of joint (with examples)?
- Fibrous (teeth sockets)
- Cartilaginous (Intervertebral discs)
- Synovial (metacarpophalangeal and knee joint)
What is a synovial joint?
Articulating bones seperated by fluid filled cavity. Most joints are this.
What are osteophytes?
Bone lumps (bone spurs) that grow around the joints or spine.
What is the main presentation of osteoarthritis?
Joint pain and stiffness-usually worsened by activity.
Also leads to deformity, instability and reduced function.
What are the most commonly affected joints in osteoathritis?
Hips Knees Sacro-iliac joints Distal-interphalangeal joints MCP (base of thumb) Wrist Cervical spine
What are the signs of osteoarthritis in the hands?
Heberden's nodes (DIP joints) Bouchard's nodes (PIP joints) Squaring at base of thumb Weak grip Reduced range of motion
How is osteoarthritis managed?
- Lifestyle changes: weight loss, physiotherapy to improve strength to support joint, occupational therapy, orthotics.
- Stepwise analgesia:
1. Paracetamol/ topical NSAIDS/ capsaicin
2. Add oral NSAIDS (and protective PPI)
3. Consider opiates (codeine/ morphine) - Intra-articular steroid injections
- Joint replacement in severe cases.
What is rheumatoid arthritis?
Autoimmune condition that causes chronic inflammation of the synovial lining of the joints, tendon sheaths and bursa
What is a bursa?
Small fluid-filled sac lined by synovial membrane with an inner capillary layer of viscous synovial fluid. Provides a cushion and reduces friction between the surfaces of bone and soft tissue.
What is a tendon sheath?
Thin layer of tissue surrounding each tendon in the body.
What type of arthritis is rheumuatoid?
Inflammatory symmetrical polyarthritis (affects multiple joints and is symmetrical)
In which gender is rheumatoid arthritis more common?
3X more common in women than men
What is Rheumatoid Factor (RF)?
An autoantibody present in around 70% of RA patients. Targets the Fc portion of the IgG antibody, activating the immune system.
What are cyclic citrullinated peptide antibodies (anti-CPP antibodies)?
Autoantibodies that are more sensitive and specific to RA than rheumatoid factor.
What are the key presentations of rheumatoid arthritis?
Symmetrical distal polyarthropathy (joint pain):
- Pain
- Swelling
- Stiffness
Where does RA usually start and how quick is onset?
Usually complain of pain/stiffness in small joints of hands, feet, wrist, ankle, MCP/ PIP joints. Onset can be very rapid (overnight) or over months to years.
What are the systemic symptoms associated with RA?
Fatigue
Weight loss
Flu like illness
Muscle aches and weakness.
What is palindromic rheumatism?
Self limiting short episodes of inflammatory arthritis that typically last 1-2 and then resolve.
What are the most common joints affected in RA?
Proximal interpharangeal joints (PIP) Metacarpophalangeal (MCP) joints Wrist and ankle Metatarsophalangeal joints (in foot) Cervical spine Large joints (knee, hips, shoulders)
What is atlantoaxial subluxation?
Disorder of C1-C2 causing impairment in rotation of the neck. Caused by local synovitis and damage to the ligaments and bursa around the odontoid peg of the axis and atlas.
Can cause spinal cord compression and is an emergency.
What are common signs og RA in the hands?
- ‘Boggy’ feeling when palpating synovium around joints.
- Z-shaped deformity of thumb
- Swan shaped neck deformity (of fingers)
- Boutonnieres deformity (hyperextended DIP with flexed PIP)
- Ulnar deviation of the fingers at the knuckle (MCP joints)
What other extra-articular (outside of a joint) manifestations may be present in RA?
- Pulmonary fibrosis
- Bronchiolitis obliterans
- Felty’s syndrome
- Secondary Sjogren’s syndrome
- Anaemia of chronic disease
- Cardiovascular disease-
- Episcleritis/ scleritis
- Rheumatoid nodules
- Lymphadenopathy
- Carpal tunnel
- Amyloidosis
What investigations are done with suspected RA?
If there is Symmetrical polyarthropathy affecting small joints:
- Check rheumatoid factor- if negative, check anto-CCP antibodies
- Inflammatory markers (CRP/ ESR)
- X-ray hands and geet
- Ultrasound of joints can be used to confirm synovitis.
What X-ray changes would be seen in RA?
- Joint destruction and deformity
- Soft tissue swelling
- Periarticular osteopenia
- Bony erosions
How is RA diagnosed?
Patients scored based on: 1. Joints involved 2. Serology (RF and anti-CCP) 3. Inflammatory markers (ESR and CRP) 4. Duration of symptoms (> or < 6 weeks) Scores added up and >6 = arthritis
What is the DAS28 score?
Disease activity score for RA: Assessment of 28 joints and points are given for swollen joints, tender joints and ESR/ CRP results.
What factors indicate a worse prognosis in RA?
Younger onset Male More joints/ organs affected Presence of RF and anti-CCP Erosion seen on X-ray
What treatment is given at first presentation of RA and in subsequent flare ups?
Short course steroids to quickly settle disease.
Why are NSAIDS/COX-2 inhibitors often avoided in RA?
Risk GI bleed (can be co-prescribed with PPIs)
What are the guidelines for the prescription of disease modifying anti-rheumatic drugs (DMARDs)?
1st line: Monotherapy (methotrexate, leflnomide, sulfasalazine)
2nd line: Two of these in combination
3rd line: Methotrexate + biological therapy (TNF inhibitor)
4th line: Methotrexate + rituximab)
What are the different types of biological therapies to treat RA?
Anti-TNF's (Adalimumab, infliximab, etanercept) Anti-CD20 (Rituximab) Anti-IL6 Anti-IL6 receptor JAK inhibitors
What is the problem with biological therapies?
They all lead to immunosuppression so patients are prone to serious infections. Can also lead to reactivation of dormant infections (E.g. TB or Hep B)
How does Methotrexate work?
Interferes with the metabolism of folate and suppresses components of the immune system–> Reduces function of cells that cause inflammation of the joints (needs to be taken with folic acid)
What are the main side effects of methotrexae?
Mouth ulcers Liver toxicity Pulmonary fibrosis Bone marrow suppression and leukopenia Teratogenic (harmful to pregnancy)
What is leflunomide and how does it work?
Immunosuppressant that works by interfering with the production of pyrimidine (component of RNA/ DNA)
What is Sulfasalzine and how does it work?
Immunosuppressive and anti-inflammatory with unclear mechanism.
What is Hydroxychloroquine and how does it work?
Immunosuppressive that inteferes with Toll-like receptors, disrupting antigen presentation and increasing pH in lysosomes of immune cells.
What are Anti-TNF drugs and how do they work?
Tumour necrosis factor= cytokine involved in stimulating inflammation. Therefore, blocking it reduces inflammation. (most are monoclonal antibodies to TNF)
What is Rituximab and how does it work?
Monoclonal antibody that targets CD20 protein on surface of B cells, causing their destruction. Used for immunosuppression.
What are Spondyloarthropathies ?
Forms of arthritis that form in the bones of the spine and nearby joints.
What is psoriatic arthritis?
Inflammatory arthritis associated with psoriasis.
What is arthritis mutilans?
Most severe form of psoriatic arthritis: condition where the joint is completely destroyed
What are the different patterns psoriatic arthritis can take on?
Symmetrical polyarthritis
Asymmetrical pauciarthritis
Spondylitic pattern
What is pauciarthritis?
When the arthritis only affects a few joints.
How does spondylitic pattern psoriatic arthritis usually present?
More common in men:
Back stiffness
Sacroilitis
Atlanto-axial joint involvement
What are the key signs of psoriatic arthritis?
Plaques of psoriases on skin
Pitting of nails
Onycholysis (seperation of nail from nail bed)
Dacytlitis (inflammation of full finger)
Enthesitis (Inflammation of points where tendons insert onto bone)
How is psoriatic arthritis screened for?
People with psoriases complete PEST (Psoriasis epidemiological screening tool) test.
What X-ray changes are seen with psoriatic arthritis?
Periostitis (inflammation of periosteum) Ankylosis Osteolysis Dactylitis Pencil-in- cup appearance of digits
What is ankylosis?
Where bones joining together causes joint stiffness
How is psoriatic arthritis managed>
Same as rheumatoid: NSAIDS for pain DMARDS (methotrexate, leflunomide, sulfasalazine) Anti-TNFS Usterkinumab (last line)
What is reactive arthritis?
(REITER SYNDROME) Where synovitis occurs in the joints as a reaction to a recent infective trigger.
What does reactive arthritis cause/ present with?
Acute monoarthritis- inflammation of single joint (usually the knee), presenting with warm, swollen and painful joint.
What are the most common infections to trigger reactive arthritis?
Gastroenteritis, STI’s (chlamydia, gonorrhoea)
What other problems can reactive arthritis cause?
-Bilateral conjunctivitis
-Anterior uveitis (inflammation of middle layer of eye)
-Circinate balanitis (dermatitis of penis head)
(CAN’T SEE, PEE OR CLIMB A TREE)
How is reactive arthritis managed?
Antibiotics given until septic arthritis excluded.
Aspirate joint and send sample to exclude septic arthritis.
NSAIDS
Steroid injection to joint
What is ankylosing spondylitis?
Inflammatory condition mainly affecting the spine that causes progressive stiffness and pain.
What gene do the seronegative spondyloarthropathy conditions relate to?
HLA B27 gene.
What key joints are affected in ankylosing spondylitis?
Sacroiliac joints, joints of vertebral column.
What are the main presenting features of ankylosing spondylitis?
Lower back pain and stiffness
Sacroiliac pain in buttock region.
(Worse with rest and improves with movement, is worse at night and in the morning- takes at least 30 mins for stiffness to improve)
What are key complications of ankylosing spondylitis?
Verterbal fractures
Fusin of the spine or sacroiliac joints (bamboo spine on X-ray)
What is the usual onset of ankylosing spondylitis?
Gradual development of symptoms over > 3 months
What other organ systems can ankylosing spondylitis affect and what does it cause?
Systemic symptoms: Weight loss, fatigue Chest pain (costovertebral/ sternal joints) Enthesitis Dactylitis Anaemia Anterior Uveitis Aortitis Heart block Restrictive lung disease Pulmonary fibrosis IBS
What is Schober’s test?
Assessment of mobility of spine:
Patient stands straight, L5 found and marks placed 10cm above and 5cm below. Patient bends forward and distance between points measured.
If < 20cm, indicates restriction in lumbar movement.
What investigation can be done to diagnose ankylosing spondylitis?
Schobers test Inflammatory markers (CRP, ESR) HLA B27 Genetic testing Xray of spine and sacrum MRI of spine (bone marrow oedema)
What X-ray changes may be seen in ankylosing spondylitis?
Bamboo spine (vertebrae fusion) Squaring of vertbral bodies Subchondral sclerosis/ erosions Syndesmophytes Ossification Fusion of joints
How is ankylosing spondylitis managed?
NSAIDS Steroids Anti-TNFs Secukinumab Lifestyle changes: physio, exercise, avoid smoking
What is SLE?
Systemic lupus erythematosus (lupus): Inflammatory autoimmune connective tissue disease.
What is the pathophysiology of lupus?
Anti-nuclear antibodies (antibodies to proteins in the patients nucleus) cause an immune response that targets these proteins, initiating systemic inflammatory response.
What is erythematosus?
Red molar rash that occurs across the face in lupus
What are the symptoms of SLE?
Usually relapse-remitting course with flare ups:
- Fatigue
- Weight loss
- Arthralgia (joint pain)/ arthritis
- Myalgia (muscle pain)
- Fever
- Photosensitive malar rash (nose and cheeks)
- Lymphadenopathy/ splenomegaly
- Shortness of breath
- Pleuritic chest pain
- Mouth ulcers
- Hair loss
- Raynauds phenomenon
What is Raynaud’s phenomenon?
When the fingers and toes change colour due to cold, anxiety or stress
What investigations are done in SLE?
Autoantibodies
Full blood count (normocytic anamia of chronic disease)
C3/4 levels
CRP and ESR
Immunoglobulins
Urinalysis and urine protein:creatinine ratio
Renal biopsy
What is the initial investigation when someone presents with SLE symptoms?
ANA (anti-nuclear antibody) blood test (present in 80% of cases)
What autoantibodies are indicative of SLE?
Anti-nuclear antibodies (80%)
Anti-double stradned DNA (Anti-dsDNA) (70%- specific to SLE)
Anti-extractable nuclear antigen antibodies (anti-ENA antibodies)
What are the main complications of SLE?
Cardiovascular disease Infection Anaemia of chronic disease Pericarditis Pleuritis Interstitial lung disease Lupus nephritis Neuropsychiatric SLE Recurrent miscarriage Venous thromboembolism
How does SLE cause cardiovascular disease?
Chronic inflammation in blood vessels leads t hypertension and coronary artery disease
How is SLE treated?
Anti-inflammatories and immunosuppression: NSAIDS Steroids Hydroxychloroquine Methotrexate e.t.x. Biological therapies (Rituximab)
What is discoid lupus erythematosus?
Chronic skin condition, causing photosensitive lesions on face, ears and scalp.
What is osteoporosis?
Condition that causes reduction of bone density
What is osteopenia?
Reduced bone mineral density that is not as severe as osteoporosis
What does reduced bone density make bones more at risk of?
Fractures
What are the risk factors for osteoporosis?
Older age Female Reduced mobility/activity Low BMI (<18.5) Rheumatoid arthritis Alcohol/ smoking Long term corticosteroids Other medications (SSRIs, PPIs, Anti-epileptics)
What group of people are most at risk of osteoporosis and why?
Post-menopausal women and oestrogen is protective against it.
What is the FRAX tool?
Gives a prediction of the risk of a fragility fracture in the next 10 years.
Involves inputting information such as age, BMI, co-morbidities, risk factors e.t.c. and gives % 1- year probability of major osteoporotic or hip fracture
What does a DEXA scan measure and what does DEXA stand for?
Bone mineral density
Dual-energy xray absorptiometry
How do DEXA scans work?
Use brief X-ray scans that measure how much radiation is absorbed by the bones, indicating how dense they are.
Where is the most common location for performing a DEXA scan?
T-score at Hip.
How is bone density represented?
Z score/ T score:
Z score–> Number of standard deviations the patients bone density falls below mean for their age
T-score–> No. S.D’s below the mean for a healthy young adult they are.
What T-score at the hip indicates:
- Osteopenia
- Osteoporosis
- Severe osteoporosis?
- -1 to -2.5
2.
What are the steps in assessing for osteoporosis?
- FRAX assessment on patients at risk.
- If indicates intermediate risk: DEXA scan
- If high risk: offer treatment
What lifestyle changes are recommended in osteoporosis?
Lifestyle changes:
- Increase activity/ exercise
- Maintain healthy weight
- Adequate calcium intake
- Adequate vit. D
- Avoid falls
- Stop smoking
- Reduce alcohol consumption.