Musculoskeletal Flashcards
How does osteoarthritis look like on X-ray?
Loss of joint space
Osteophytes
Subarticular sclerosis
Subchondral cysts
How does synovial fluid from someone suffering from osteoarthritis look like?
Clear/straw coloured and viscous
What may be seen on X ray of someone with rheumatoid arthritis?
Soft tissue swelling
Juxta-articular osteopenia
Loss of joint space
Later… bony erosions and subluxation
What is DAS28?
A way of measuring disease activity in rheumatoid arthritis
Where would you see the “pencil in cup” deformity?
Psoriatic arthritis
Why might someone with AS experience anterior mechanical chest pain?
Costochondritis
What is the pathophysiology behind bamboo spine?
Vertebral syndesmophytes (bony growths from ligaments) fuse with vertebral body above
What are the causes of gout?
- Hereditary
- Increased dietary purines
- Alcohol XS
- Diuretics
- Leukaemia
- Cytotoxics
What are the crystals of someone with gout like?
Negatively birefringent urate crystals
What medications are available for someone experiencing an acute episode of gout?
NSAIDs, coxib, colchicine
What drug is used as prophylaxis for gout?
Allopurinol
What are allopurinol’s side effects?
Rash, fever, decreased WCC,
What is the timing of a patient with gout taking allopurinol relative to their latest acute episode?
What medication should they take alongside it then and why?
Wait until 3 weeks after an acute episode to start allopurinol and cover with an NSAID or colchicine as allopurinol may trigger an acute attack
What 3 things make up Reiter’s syndrome?
Urethritis, reactive arthritis. conjunctivitis
What happens to the following in SLE:
- ESR
- CRP
- C3 + C4
- C3d + C4d
- increased ESR
- normal CRP
- decreased C3 + C4
- increased C3d + C4d
Which antibodies are associated with SLE?
ANA positive, DNA Ab (v specific)
What malignancy is a higher risk in patients with SLE?
Non-Hodgkin’s b-cell lymphoma
What is a positive Schirmer’s test and what diagnosis does it suggest?
< 5mm in 5 mins
Suggest Sjogren’s
What is another name for “Limited cutaneous systemic sclerosis”?
CREST syndrome
What parts of the body are affected in Limited cutaneous systemic sclerosis AKA Crest syndrome?
Skin involvement limited to face, hands and feet.
Which antibody is associated with Limited cutaneous systemic sclerosis AKA Crest syndrome?
Anti-centromere antibody
Where does diffuse cutaneous systemic sclerosis affect?
Diffuse skin involvement and early organ fibrosis
What 2 investigations must be annually done in a patient suffering from diffuse cutaneous systemic sclerosis?
ECHO and Spirometry
Name 5 skin signs that may be seen in patients with dermatomyositis
- Macular rash (shawl sign)
- Heliotrope (lilac) rash on eyelids
- Nailfold erythema
- Gottron’s papules
- Subcutaneous calcifications
What is the pattern of muscle weakness seen in patients with polymyositis/ dermatomyositis?
Insiduous onset of progressive symmetrical proximal muscle weakness and myositis
What tests should be done on patients with polymyositis/ dermatomyositis?
- Increased muscle enzymes
- Electromyography: Fibrillation potentials
- Muscle biopsy
- Screen for malignancy
What are the treatment options for a patient with polymyositis/ dermatomyositis?
Prednisolone, immunosuppressives, cytotoxics Hydroxychloroquine of topical tacrolimus for skin disease
What antibodies are associated with Sjogren’s syndrome?
RhF
Anti-Ro
Anti-La
Which is the most specific antibody for RA?
Anti-CCP
Which antibody is associated with antiphospholipid syndrome?
Anti-cardiolipin antibody
Name 2 antibodies associated with polymyositis/ dermatomyositis?
Anti Mi-2 and Anti Jo-1
Which antibody is associated with diffuse systemic sclerosis?
Anti-Scl 70
What is the 1st line treatment for rheumatoid arthritis?
DMARDs
How long may it take before symptomatic benefit is gained from DMARDs?
6 - 12 weeks
Which combo of DMARDs give the best results in rheumatoid arthritis?
Methotrexate + Sulfasalazine + Hydroxychloroquine
What must you monitor for someone on DMARDs and why?
Must do regular FBC monitoring as DMARDs are immunosuppressives that can cause pancytopenia
What are the side effects of methotrexate?
Pneumonitis. oral ulcers, hepatotoxicity
What are the side effects of Sulfasalazine?q
Rash, low sperm count, oral ulcers
What is a side effect of hydroxychloroquine?
Irreversible retinopathy
At what stage would you use biologics in someone with rheumatoid arthritis?
When they have active rheumatoid arthritis after failure to respond to 2 DMARDs and with a DAS 28 of >5.1
Give an example of a type of biologic
TNFa inhibitors e.g. infliximab, etanercept
If TNFa inhibitors do not work in a patient with RA what should you try next?
B cell depletion (e.g. Rituximab)
If B cell depletion (e.g. Rituximab) doesn’t work in someone with RA what are your other options?
- IL-1 + IL-6 inhibition
- Abatacept (disrupts T cell function)
List some common organisms involved in osteomyelitis
Staph aureus; pseudomonas; E coli; streptococci
What is the pathophysiology behind a sequestrum forming? When would you see them?
Infection of the bone –> cortex erosion, holes –> pus lifts up periosteum –> interrupts blood supply and necrotic fragments may form = sequestrum.
Seen in chronic osteomyelitis
What is involucrum?
New bone that may form as a result of pus in the bone lifting up the periosteum
How might a patient describe the pain and their movement if they have osteomyelitis?
The pain is of gradual onset and the patient would be unwilling to move over a few days.
What is the gold standard way to diagnose osteomyelitis?
Bone biopsy and culture
What and when would you see x-ray changes on someone with osteomyelitis?
X-ray changes would not become apparent or 10 -14 days.
Hazziness +/- loss of density and subperiosteal reaction
How do you treat acute osteomyelitis?
6 weeks of antibiotics (Vancomycin and cefotaxime IVI), drain abscesses and remove sequestra.
What is one way you can diagnose chronic osteomyelitis and what is the treatment for it?
If bone can be felt on probing ulcer = chronic osteomyelitis
Antibiotics for at least 12 weeks
What is TB in the vertebral body called?
Pott’s disease
What is the treatment for bone TB?
Drain abscesses, immobilise joint, start a 1 year course of: Rifampicin, Isoniazid, pyrazinamide.
Gentle exercise
How would a bone sarcoma present?
Non-mechanical bone joint pain, bone pain at night, bony swellings and pathological fractures
What is the most common type of primary malignant bone tumour? What lesions would it show on X-ray?
Multiple myeloma. Multiple punched-out osteolytic lesions
Who tends to develop primary sarcoma and it which bones does this tend to happen in?
Primary sarcoma commonly affects teens. Tends to occur in the metaphysis of long bones, especially around the knee)
Give 2 circumstances where secondary sarcoma is more likely?
Paget’s disease and after irradiation