Ankylosing Spondylitis & Gouts Flashcards
What is Ankylosing Spondylitis?
- Ankylosing spondylitis is a HLA-B27 associated spondyloarthropathy.
- It typically presents in males (sex ratio 3:1) aged 20-30 years old
What are features of Ankylosing Spondylitis?
- Typically a young man who presents with lower back pain and stiffness of insidious onset
- Stiffness is usually worse in the morning and improves with exercise
- Patient may experience pain at night which improves on getting up
What are examination findings of Ankylosing Spndylitis?
- Reduced lateral flexion
- Reduced forward flexion
- Schober’s test - a line is drawn 10 cm above and 5 cm below the back dimples (dimples of Venus). The distance between the two lines should increase by more than 5 cm when the patient bends as far forward as possible
- Reduced chest expansion
What are extra-articular features of Ankylosing Spondylitis?
- Apical fibrosis
- Anterior uveitis
- Aortic regurgitation
- Achilles tendonitis
- AV node block
- Amyloidosis
- and cauda equina syndrome
- peripheral arthritis (25%, more common if female)
What are blood tests and typical result in Ankylosing spondylitis?
- CRP and ESR may be elevated but can be normal. This does not exclude ankylosing spondylitis
- HLA-B27 is of little use in making the diagnosis as it is positive in:
- 90% of patients with ankylosing spondylitis
- 10% of normal patients
What are radiological investigations in Ankylosing Spondylitis?
- MRI of the spine and Sacroiliac joints is more sensitive for early disease
- X-ray of the sacroiliac joints and spine is the most useful investigation in establishing the diagnosis in later disease.
What are the changes seen on X-Ray for Ankylosing Spondylitis?
Radiographs may be normal early in disease, later changes include:
- Sacroiliitis: subchondral erosions, sclerosis
- Squaring of lumbar vertebrae
- ‘Bamboo spine’ (late & uncommon)
- Romanus lesions
- Syndesmophytes: due to ossification of outer fibres of annulus fibrosus
- Chest x-ray: apical fibrosis
What other investigations can be performed to assess effects of Ankylosing Spondylitis?
Spirometry may show a restrictive defect due to a combination:
- Pulmonary fibrosis
- Kyphosis
- Ankylosis of the costovertebral joints.
How is Ankylosing Spondylitis managed?
- Encourage regular exercise such as swimming
- Physiotherapy
- NSAIDs are the first-line treatment
- The disease-modifying drugs which are used to treat rheumatoid arthritis (such as sulphasalazine) are only really useful if there is peripheral joint involvement
- TNF inhibitor, IL-17 inhibitors if DMARDs fail
What is Gout?
- Form of microcrystal synovitis caused by the deposition of monosodium urate monohydrate in the synovium.
- It is caused by chronic hyperuricaemia (uric acid > 0.45 mmol/l)
What are caauses of Gout?
- Decreased excretion of uric acid
- drugs*: diuretics
- chronic kidney disease
- lead toxicity
- Increased production of uric acid
- Myeloproliferative/lymphoproliferative disorder
- Cytotoxic drugs
- Severe psoriasis
What can Gout lead to ?
- Acute and chronic arthritis
- Soft tissue masses called tophi
- Urate nephropathy
- Uric acid nephrolithiasis.
What are investigations done for diagnosis of Gout?
- Urate levels
- Monosodium Urate crystals found in synovial fluid aspirate are pathognomonic for gout
- Urate crystals are negatively birefringent through polarised light.
What are some risk factors for Gout?
- Non-modifiable factors
- Age >40 years
- Male gender
- Modifiable factors
- Increased purine uptake (meats and seafood) Alcohol intake (especially beer)
- High fructose intake
- Obesity
- Congestive heart failure
- Coronary artery disease
- Dyslipidemia
- Renal disease
- Organ transplant
- Hypertension
- Smoking
- Diabetes mellitus
- Urate-elevating medications e.g. diuretics
How can Gout be prevented?
- Maintain optimal weight
- Regular exercise
- Diet modification (purine-rich foods)
- Reduce alcohol consumption (beer and liquor)
- Smoking cessation
- Maintain fluid intake and avoid dehydration
What is the acute management of Gout?
- 1st line: NSAIDs or Colchicine
- Gastroprotection may also be indicated
- Colchicine* has a slower onset of action. The main side-effect is diarrhoea
- Oral steroids may be considered if NSAIDs and colchicine are contraindicated.
- A dose of prednisolone 15mg/day is usually used
- Another option is intra-articular steroid injection
- if the patient is already taking allopurinol it should be continued
What are indications for urate-lowering therapy (ULT)?
- All patients after their first attack of gout
- ULT is particularly recommended if:
- >= 2 attacks in 12 month
- Tophi
- Renal disease
- Rric acid renal stones
- Prophylaxis if on cytotoxic or diuretics
What are Urate Lowering Therapy?
-
1st Line: Allopurinol (febuxostat can be used instead if not tolerated)
- Initial dose of 100 mg od, with the dose titrated every few weeks to aim for a serum uric acid of < 300 µmol/l. Lower initial doses should be given if the patient has a reduced eGFR
- Xanthine oxidase inhibitors (both)
- colchicine cover should be considered when starting allopurinol.
- Benzbromarone and sulfinpyrazone are used less commonly as more side effects. They act to increase renal excretion of uric acid.
- Aim to reduce SUA to < 360micromol/L
What other medications can be considered in patients with Gout?
- Losartan has a specific uricosuric action and may be particularly suitable for the many patients who have coexistent hypertension
- Increased vitamin C intake (either supplements or through normal diet) may also decrease serum uric acid levels
What is Psoriatic Arthropathy?
- Psoriatic arthropathy correlates poorly with cutaneous psoriasis and often precedes the development of skin lesions.
- Around 10-20% percent of patients with skin lesions develop an arthropathy with males and females being equally affected
What are examination findings of Psoriatic Arthropathy?
- Oligo-arthritis with dactylitis or sausage digit
- Can be symmetrical arthritis.
- Severe deformities (arthritis mutilans)
What are investigations for Psoriatic Arthropathy?
- CRP often raised
- Central joint erosion seen early on ultrasound or MRI leading to ‘pencil in cup’ x-ray appearance
What is the management of Psoriatic Arthropathy?
- Treat as rheumatoid arthritis but better prognosis
- NSAIDs, DMARDs, TNF inhibitors, IL-17 inhibitors, IL12/23 inhibitors.
What is Pseudogout?
Pseudogout is a form of microcrystal synovitis caused by the deposition of calcium pyrophosphate dihydrate in the synovium
What are Risk Factors for Pseudogout?
- Hyperparathyroidism
- Hypothyroidism
- Haemochromatosis
- Acromegaly
- Low magnesium
- Low phosphate
- Wilson’s disease
What are features of Pseudogout?
- Knee, wrist and shoulders most commonly affected
- Joint aspiration: weakly-positively birefringent rhomboid shaped crystals
- X-Ray: chondrocalcinosis
How is Pseudogout managed?
- Aspiration of joint fluid, to exclude septic arthritis
- NSAIDs or intra-articular, intra-muscular or oral steroids as for gout
