Rheumatology Flashcards
List 4 seronegative spondyloarthropathies
Ankylosing spondylitis
Psoriatic arthritis
Reactive arthritis
Enteropathic arthritis
Which seronegative spondyloarthropathies are more prevalent in males? (2)
Ankylosing spondylitis
Reactive arthritis
Which skin lesions can be seen in which seronegative spondyloarthropathies?
AS - rare to have skin lesions
Psoriatic arthritis - 100% psoriasis
Reactive arthritis - common - keratoderma blennorrhagica
Enteropathic arthritis - occasional - pyoderma, erythema nodosum
How common is the HLA-B27 marker in the seronegative spondyloarthropathies?
90% in AS
40% in PsA
80% in ReA
30% in EnA
In which seronegative spondyloarthropathies is sacroiliitis more common?
AS and ReA (compared to PsA and EnA)
What is the point of HLA-B27? (4) List disadvantages
- Not routine/diagnostic/confirmatory
- Cannot be used as a screening test for AS in the general population
- Sensitivity and specificity depends on racial/ethnic background of patient
- Does not help distinguish AS from other B-27 associated spondyloarthropathies
What postural changes can be seen in ankylosing spondylitis?
Decreased lumbar lordosis + increased thoracic kyphosis + increased cervical flexion = increased occiput to wall distance (>5 cm)
What is the most common extra-articular manifestation of ankylosing spondylitis?
Acute anterior uveitis - occurs relatively more commonly in HLA B-27 positive compared with those who lack the gene
In which seronegative spondyloarthropathies can aortic regurgitation occasionally occur?
AS
ReA
EnA
Rare in PsA
Describe the aetiology and pathophysiology of AS.
Relatively undetermined
Enthesitis thought to be source: inflammation –> osteopaenia –> erosion –> ossification –> osteoproliferation (syndesmophytes) which causes inflammatory low back pain
What is ankylosing spondylitis?
Chronic systemic inflammatory disorder of undetermined aetiology, usually beginning in early adulthood, primarily affecting the axial skeleton (but can peripheral arthritis and enthesitis) but can exhibit some extra-articular features (opthalmic, renal, gastro, cardiac, respiratory,neurologic)
What kind of pain is experienced in ankylosing spondylitis? (2)
- Inflammatory low back paine from syndesmophyte formation and/or buttock pain from sacroiliitis
- Inflammatory characteristic - nocturnal rest pain, early morning stiffness, relief with NSAIDs
Describe sacroiliitis pain. (2)
- Dull in character, difficult to localise and felt somewhere deep in the gluteal region
- May be unilateral or intermittent at first; however within a few months it generally becomes persistent and bilateral and the lower lumbar spine area also becomes painful
Describe the crystals seen in gout.
Monosodium urate –> needle-shaped, negatively birefringent (yellow)
Describe the crystals seen in pseudogout
calcium pyrophosphate dihydrate –> rhomboid-shaped, positively birefringent (blue)
Which tests can be used to measure spinal mobility in ankylosing spondylitis? (4)
- Modified Schober’s test - decreased forward flexion
- Lumbar side flexion: decreased
- Occiput-to-wall distance: increased
- Chest expansion: abnormal (<5 cm)
What investigations would you order in ankylosing spondylitis? (4)
- X-ray - appearance of radiographic abnormalities typically delayed - reactive sclerosis (Romanus lesion), squaring and erosions at the edge of the vertebral bodies to syndesmophyte formation and bony bridging i.e. ossification of outer fibres of annulus fibrosis - “bamboo spine”; interspinous ligament calcification ‘dagger spine’
- MRI - useful in EARLY DIAGNOSIS; good at detecting oedema or vascularised fibrous tissue, enthesitis of interspinous ligaments
- US - useful in detecting enthestisis
- Lab tests - ESR/CRP - only elevated in 50-70% of AS patients; HLA-B27 (90% of those with AS have this marker; but not all those with this marker will develop AS)
How is AS managed? (3)
Symptom management
- education and exercise
- NSAIDs
- TNF inhibitors - for patients with inadequate responst to NSAIDs
What is the first line therapy of Ankylosing Spondylitis?
NSAIDs
In which type of spondyloarthropathy should NSAIDs be used in caution?
Enteropathic
How is psoriatic arthritis managed? (3)
- Treat skin lesions (e.g. steroid cream, salicylic and/or retinoic acid, tar, UV light)
- NSAIDs or intra-articular steroids
- DMARDs, biologic therapies to minimise erosive disease
Which dermatological features are diagnostic of ReA?
Keratoderma blenorrhagicum (hyperkeratotic skin lesions of palms and soles) and balanitis circinata (small, shallow, painless ulcers of glans penis and urethral meatus)
How is ReA investigated? (3)
CLINICAL PLUS LABORATORY DIAGNOSIS
- Bloodwork - normocytic, normochromic anaemia and leukocytosis
- Sterile cultures
- Serology: HLA-B27
List 2 primary causes of hyperuricaemia.
- Mostly due to idiopathic renal underexcretion
2. Idiopathic overproduction or abnormal enzyme production/function