Musculoskeletal Flashcards
(177 cards)
Definition of ankylosing spondylitis:
Ankylosing spondylitis is a seronegative inflammatory arthritis, primarily involving the axial skeleton. It is a type of axial spondyloarthritis known as radiographic axial spondyloarthritis, meaning that there are X-ray changes such as sacroiliitis (versus non-radiographic axial spondyloarthritis, where there may be changes visualised on MRI but not on X-ray.
What is the most important genetic factor for ankylosing spondylitis?
HLA-B27
What is an important modifiable risk factor for ankylosing spondylitis?
Smoking is an important modifiable risk factor
What are the musculoskeletal symptoms of ankylosing spondylitis
Lower back and buttock pain - alternating buttock pain
Pain elsewhere in the spine may also occur
Stiffness that is worse in the morning and with rest, and improves with activity
Patients may wake in the second half of the night with pain
Pain and stiffness respond to NSAIDs
Peripheral enthesitis (pain, stiffness and/or swelling of the Achilles, quadriceps or patellar tendons, as well as plantar fasciitis)
Peripheral arthritis occurs in up to a third of patients, commonly affecting the ankles, knees and hips
What are the extra-articular involvements of ankylosing spondylitis?
Anterior uveitis (eye pain, redness and blurred vision)
Inflammatory bowel disease (e.g. diarrhoea, abdominal pain, rectal bleeding)
Osteoporosis (increased risk of fragility fractures)
Aortitis which may lead to aortic regurgitation (shortness of breath, fatigue, chest pain)
Upper lobe pulmonary fibrosis (shortness of breath, exercise intolerance, dry cough)
IgA nephropathy (haematuria, fatigue)
Systemic symptoms of weight loss and fatigue
Triple A: anterior uveitis (most common), aortic insuffiencies and apical pulmonary fibrosis.
Signs on examination of ankylosing spondylitis
Restricted movement in the lumbar spine
Schober’s test can be used to assess this as follows:
Mark two points on the back (one at the level of the L5 spinous process and one 10 cm above this)
On forward flexion, the distance between the two points should increase by 5cm or more
If the increase in distance is <5 cm, this indicates restricted forward flexion
Hyperkyphosis of the thoracic spine may develop as the disease progresses
Reduced C-spine movements and fixed flexion deformities may be seen
This can be measured by asking the patient to stand with their back to the wall
A distance of > 2 cm between their occiput and the wall is abnormal
“Question mark posture” refers to the combination of thoracic hyperkyphosis, loss of the lumbar lordosis and flexion deformities of the neck and hips (seen in advanced disease)
Reduced chest expansion may be seen
Affected joints may be tender and swollen
Affected tendons may be tender, stiff or swollen
What would you expect to see on a blood test of ankylosing spondylitis?
FBC which may show anaemia of chronic disease
ESR and CRP are often raised due to inflammation
HLA-B27 positivity supports a diagnosis but a negative result shoudl not rule out ankylosing spondylitis
What are the image investigations for ankylosing spondylitis?
Pelvic X-rays looking for sacroiliitis
This is usually bilateral and symmetrical
In early disease, sclerosis or erosion of the sacroiliac joints may be difficult to visualise
In advanced disease, there is ankylosis or fusion of the joint
Lumbar X-rays may show squaring of the vertebral bodies
In late disease, there is ossification of spinal ligaments (“dagger sign”)
Fusion of the vertebral column by syndesmophytes may be seen (“bamboo spine”)
MRI may be required if X-rays are normal - MRI is the gold standard
Sensitivity for sacroiliitis is higher especially in early disease
Ultrasound or X-rays of other sites of pain may be indicated e.g. for enthesitis or peripheral arthritis
DEXA scans may be used to assess bone density
Signs of osteopenia or osteoporosis may be seen on other imaging also
DEXA imaging of the spine may be inaccurate due to syndesmophytes and calcification of ligaments (hip measurements tend to be more reliable)
Conservative management for ankylosing spondylitis?
Referral to rheumatology for confirmation of the diagnosis and ongoing management
Involvement of other specialties may be required for extra-articular manifestations e.g. emergency ophthalmology assessment for suspected anterior uveitis
Smoking cessation counselling
Physiotherapy referral for a structured exercise programme to optimise mobility
Occupational therapy, orthotics or podiatry input may be required to help maximise function
Monitor bone density and consider bone protection for osteoporosis
Assess cardiovascular risk and consider initiating treatment (e.g. statins)
What is the medical management for ankylosing spondylitis?
NSAIDs as the first-line treatment
These should be used at the lowest effective dose
Symptoms should improve in 2-4 weeks
Switching to a different NSAID should be considered before escalating treatment
Consider co-prescribing a PPI to prevent peptic ulceration
Paracetamol +/- codeine may be trialled if NSAIDs are contraindicated
Adjuncts for analgesia include local steroid injections
Biological DMARDs are the next step in treatment of severe disease if response to NSAIDs is inadequate
Anti-TNF agents such as infliximab or adalimumab are the treatment of choice
Secukinumab (an anti-IL17A biologic) is another option
Regular monitoring is required for patients on these medications
They are usually highly effective
Conventional disease-modifying antirheumatic drugs (DMARDs) such as sulfasalazine and methotrexate are not effective for axial arthritis but may be used for peripheral involvement
Topical cyclopentolate for the anterior uveitis
What is the surgical management for ankylosing spondylitis?
Referral to spinal surgery for patients with complications such as suspected spinal fractures or cauda equina syndrome
Surgery to correct spinal deformities may be indicated in some patients with severe disease significantly affecting quality of life
Total hip replacement may be considered in patients with structural damage leading to refractory hip pain and/or difficulty mobilising
What are the complications for ankylosing spondylitis?
Spinal deformities including fusion of the axial skeleton in severe cases
Limited mobility
Deterioration in mental health due to chronic pain and limitations in function
Sleep difficulties due to pain and stiffness
Osteoporosis and spinal fractures
Increased cardiovascular risk
Heart failure
Aortic regurgitation and other valvular disorders
Restrictive lung disease
Apical pulmonary fibrosis
IgA nephropathy
Anterior uveitis
Side effects from treatment e.g. immunosuppression with DMARDs, peptic ulcers with NSAIDs
What is the prognosis for ankylosing spondylitis?
Ankylosing spondylitis tends to be a progressive disease involving irreversible damage - however the course of the disease is variable and effective and prompt treatment minimises disability.
Good prognostic factors include:
Low functional impairment at diagnosis
Young age at disease onset
Short disease duration
High inflammatory markers at diagnosis
Key signs and symptoms of crystal arthropathies?
joint pain and swelling, often affecting one joint at a time
What is the most important investigation to confirm a crystal arthropathy?
Joint aspiration with subsequent polarised-light microscopy, culture and sensitivity is the gold standard:
The fluid may appear milky
On microscopy, a raised white cell count may be seen (typically <50 × 109/l – values above this are more indicative of septic arthritis)
Crucially, the presence of crystals on polarised light microscopy confirms the diagnosis
Note: It is important to send the fluid for Gram stain and culture to exclude the diagnosis of septic arthritis.
What is gout caused by?
Caused by monosodium urate crystals
What do you see on light microscopy of gout?
negatively birefringent and needle-shaped on light microscopy
Gout has Negatively birefringent, Needle-shaped crystals
What is pseudogout caused by?
Caused by calcium pyrophosphate dihydrate crystals
What do you see on light microscopy of pseudogout?
Pseudogout has Positively birefringent, rhomboid-shaped crystals
What blood tests do we do for gout?
Uric acid (gout only) – It is important to monitor uric acid levels in recurrent gout (A serum urate of 360 micromol/L or more confirms the diagnosis) and urate-lowering therapies reduce the risk of further attacks note: urate levels often fall during an acute episode of gout so are not often useful in the diagnosis of acute gout
There is no equivalent test for pseudogout
Renal function (gout only) – Renal impairment is a risk factor for gout
Inflammatory markers – These may be raised as in any inflammatory arthritis
What would you see in an X-ray for gout?
Gout – may be useful as a baseline
X-ray changes (aside from soft-tissue swelling) are usually not seen until multiple attacks of gout have occurred, and can then include:
Tophi
“rat bite” Erosions
Subchondral sclerosis
What would you see in an x-ray for pseudogout?
Chondrocalcinosis (calcification of cartilage)
The changes that are seen in osteoarthritis include:
Loss of joint space
Osteophytes
Subarticular sclerosis
Subchondral cysts
What would you see in a ultrasound of gout?
The double-contour sign is the most sensitive ultrasound finding of gout
A hyperechoic irregular band over the superficial margin of the articular cartilage
Gouty tophi and erosions may be seen
Define gout:
Gout is a form of arthritis that occurs when monosodium urate crystals deposit in joints. This causes both acute inflammation (gout flares) and in the longer-term, a chronic gouty arthritis with tophi (hard deposits of monosodium urate crystals in soft tissues).