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60 Cards in this Set
- Front
- Back
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What is the definitive diagnosis for gout?
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Demonstration of monosodium urate (MSU) crystals in aspirated synovial fluid
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What is the definitive diagnosis for pseudogout?
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Demonstration of calcium pyrophosphate (CPP) in aspirated synovial fluid
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Why do men tend to have a higher rate of gout than women?
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Oestrogenic hormones have uricosuric effect (increase the excretion of uric acid in the urine)
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What is your risk of a 2nd attack of gout after 1, 2 and 10 years?
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1 year - 62%
2 years - 78% 10 years - 93% |
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Do average uric acid levels correlate well with symptoms of gout?
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No, acute changes in the levels do
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Describe the formation of uric acid
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End-stage product of purine metabolism, product of xanthine oxidase catalysed conversion of xanthine and hypoxanthine
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How is uric acid excreted?
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Renal 70%
Gut 30% |
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What is the most common cause of gout?
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Under-excreted by kidneys (90%), only 10% overproduction or consumption
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What initiates an attack of gout?
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Loss of normal apoE or apoB coating of crystals, which enables activation of immune cells (macrophages and dendritic cells)
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How does an attack of gout end?
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Clearance of damaged neutrophils, recoating of urate crystals, production of anti-inflammatory cytokines (IL10, TGF-b)
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Is gout usually mono- or poly- arthritic?
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Monoarthritic at 90%
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What is podagra?
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Gout of the big toe (metatarsal-phalangeal joint of great toe); initial joint in 50%, eventually involved in 90%
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How does timing of onset differ between gout and pseudogout?
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Gout is abrupt, max at 8-12 hours
Pseudogoout is lower, insidious, over several days |
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Define hyperuricaemia
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Males > 0.42 mmol/L
Females > 3.6 mmol/L |
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What is the cut-off level for urinary uric acid?
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> 800mg over 24 hours = over excretor and over producer
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Describe gout and psuedogout crystals under polarising microscopy
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Gout - strongly negative birefringent needle-shaped crystals
Psuedogout - weakly positive birefringent rhomboidal crystals |
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What does the synovial fluid look like in gout?
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Opaque, creamy-yellow, reduced viscosity, increased cell count
Gram +ve, culture -ve |
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What are the radiological features suggestive of gout?
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Soft tissue swelling, punched out, cookie-cutter borders surrounding erosions, lytic areas with overhanging edges, haziness suggestive of tophi, maintenance of joint space, absence of ostepaenia, location outside the joint capsule
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How do you treat an acute attack of gout?
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Symptom relief: NSAIDs, colchicine, intra-articular steroid injections
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How do you treat gout in the long term?
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Prevent attacks - lifestyle and allopurinol to lower stores (xanthine oxidase inhibitor), can use probenecid where allopurinol is not tolerated
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What are tophi?
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Collections of urate crystals in soft tissue, e.g. helix of ear, fingers, toes
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In which joints does osteoarthritis occur?
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Synovial joints
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Risk factors for OA
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Increasing age, obesity, high BMD, women, low oestrogen, trauma, malalignment
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Prevalence of OA
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10-12%
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What is a protective factor for OA?
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Smoking
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Most common joints affected in OA?
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Knee and hip, then PIP, DIP, lumbar and cervical spine
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Describe the cartilage changes in OA
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IL1 + chondrocytes --> MMPs --> degrade cartilage matrix (esp aggrecan) --> increase H20 conc --> swelling, susceptible to injury --> fissures, focal death, decreased thickness
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Describe the bony changes in OA
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Increased trabecular thickness, cysts development (osteonecrosis due to incrased pressure), osteophyte formation, eburnation (bone on bone glossing), increased joint surface area
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Describe the other changes in OA (non cartilage or bone)
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Synovium and outer capsule thicken, surrounding muscle may atrophy
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What are the radiographic changes in OA?
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Osteophytes, joint space narrowing, subchondral sclerosis and cysts
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What is the 1st line treatment for OA?
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Local analgesia - capsaicin, methylsalicylate, diclofenac sodium
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What is giant cell arteritis?
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A granulomatous vasculitis of large and medium sized arteries, primarily affects branches of external carotid artery
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What is the major complication of GCA?
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Optic nerve ischaemia --> blindness
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Risk factors for GCA
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Age > 50, female, genetics (HLA DRB1), smoking and atherosclerosis
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What percentage of GCA has mutlinucleated giant cells?
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50%
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What are the granulomas composed of in GCA?
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T cells and macrophages
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Symptoms of GCA
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Persistent frontal/temporal headache, tenderness of scalp, PMR symptoms, extremity and jaw claudication, loss of vision (20%)
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What will a temporal artery biopsy show in GCA?
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Granulomatous inflammation and mulinucleated cells
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What will a temporal artery U/S show in GCA?
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Wall thickening (halo sign), stenosis or occlusion
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Treatment for GCA
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Prednisolone (1mg/kg/day PO for 4 wks), aspirin, osteperosis prevention (calcium, vit D, bisphos)
Methotrexate (7.5 mg PO once weekly) if relapsing/recurrent |
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Pathology of GCA
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CD4 T cells enter artery through vasa vasorum and undergo clonal expansion
T cells release cytokines that stimulate macrophages --> inflammation Damage and thickening/hyperplasia --> occlusion --> ischaemia |
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Epidemiology of scleroderma
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Age 40-50
Prevalence: 10-20/100,000 Females 4x |
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What does CREST stand for?
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Calcinosis, Raynaud's, Esophageal involvement, Sclerodactyly, Telangiectasia
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Classification of scleroderma
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- Diffuse(30%)
- Limited (70%) = CREST |
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What cytokines are upregulated in scleroderma?
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TGF-b, leukotriene B4, IL-1, IL-4, IL-6
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What is Raynaud's syndrome?
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At least a 2-phase colour change in fingers and often toes, consisting of pallor, cyanosis or reactive hyperaemia (redness) in response to cold or emotion
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What specific lab test are there for scleroderma?
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ANA - 90%
Anti-topoisomerase I - diffuse Anti-cetromere - limited (CREST) |
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How do you treat a scleroderma renal crisis?
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ACEi + antihypertensives
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How do you treat cardiac tamponade?
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Pericardial window, oral prednisolone and ACEi
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How do you treat Raynaud's phenomenon?
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Phosphodiesterase-5 inhibitor or endothelin-1 receptor inhibitor
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What is Sjogren's syndrome?
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An autoimmune disorder that causes dry eyes (keratoconjunctivitis sicca) and dry mouth (xerostomia) from lymphocytic infiltration into lacrimal and salivary glands
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Epidemiology of Sjogren's
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Female 9x
Prevalence 0.5-1.56% 60% have secondary to RA, SLE or systemic sclerosis Two age groups: 20-30s and mid-50s |
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What is the most unifying feature of Sjogren's syndrome?
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Ro/La ribonucleoprotein complexes (75-90%)
ANAs (90%) RF (50%) Anti-thyroglobulin antibodies (25%) |
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What is Schirmer's tear test?
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A measure of tear production, rose bengal staining and slit lamp examination to show keratitis will confirm ocular abnormality
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How do you diagnose Sjogren's syndrome?
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Sicca symptoms (xerostomia, rheumatoid arthritis and keratoconjunctivitis sicca), with polyclonal hypergammaglobulinaemia, +ve ANA and antibodies to Ro and La
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Epidemiology of SLE
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Females 12x
Age 15-45 African > Asian > Caucasian |
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Genetic factors of SLE
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Complement deficiencies (homo C2, hetero C4)
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Which antibodies are present in SLE?
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ANAs, ds-DNAs, antiphospholipid Abs,
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What is the characteristic rash in SLE?
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Malar (butterfly) rash
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What is hydroxychloroquine?
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An antimalarial and DMARD, used in SLE (200-600mg PO daily)
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