Rheum Flashcards
What is the cause of discoid lupus?
Follicular keratin plugs
What is the treatment of discoid lupus?
Topical steroids –> hydroxychloroquine
Which antibodies are most specific for SLE?
Anti-SM
Anti-dsDNA
Which antibody is most sensitive for SLE
ANA
Why are C3 and C4 low during active lupus?
Formation of immune complexes causes consumption of complement
What is the pathogenesis of SLE?
Dysregulation of IgD
What is the treatment of SLE?
Hydroxychloroquine maintenance therapy
Internal organ involvement –> AZA, CYC, ritux
Prednisolone to induce remission
Which inflammatory markers are used to monitor SLE?
ESR
As CRP may be normal during active disease; if raised may indicate underlying infection
Apart from ESR, how else is SLE monitored?
Low complement
Anti-dsDNA titres
What antibody is associated specifically with neonatal lupus erythematosus?
Anti-Ro
What are the complications/features of congenital lupus?
Heart block
Skin rashes
Hepatosplenomegaly
What percentage of psoriasis patients develop arthritis?
10-20%
What are the 5 types of psoriatic arthritis?
Symmetrical (similar to RA) Asymmetrical oligo Sacroilitis DIP joint disease Arthritis mutilans
What are other signs of psoriatic arthropathy?
Tenosynovitis
Dactylitis
Enthesitis
Nail pitting and onycholysis
What are the X-Ray appearances of psoriatic arthritis?
Co-existence of erosive changes and new bone formation
Periostitis
Pencil in cup appearance
What is rheumatoid factor?
IgM against IgG
Which HLA is RA associated with?
DR4
Especially Felty’s syndrome
What is Felty’s syndrome?
RA
Splenomegaly
Neutropaenia
What are the X-Ray features of RA?
Loss of joint space
Juxta-articular osteoporosis
Soft tissue swelling
Late - periarticular erosions, subluxation
What percentage of normal people have +ve HLA-B27?
10%
What percentage of ankylosing spondylitis patients have +ve HLA-B27?
90%
What is Schober’s sign?
An increase of less than 5cm on anterior spinal flexion when measuring the distance from 10cm above and 5cm below the left posterior iliac spine
What are the X-Ray features of ankylosing spondylitis?
Bamboo spine
Sacroilitis (subchondral erosions, sclerosis of vertebral corners)
Squaring of vertebrae
Syndesmophytes
What is bamboo spine?
Ossification of outer fibres of annulus fibrosus
What are the complications of ankylosing spondylitis?
Apical fibrosis Anterior uveitis Aortic regurgitation Achilles tendonitis AV node block Amyloidosis
What is the treatment of ankylosing spondylitis?
Exercise and physio
NSAIDs
DMARDS if peripheral joint involvement
TNF inhibitors - do not improve radiological progression
What is the most common organism causing septic arthritis?
S.aureus
Young sexually active adults - neisseria gonorrhoea
What is the cause of reactive arthritis?
Post STI form most common form in men, post-dysenteric form equal sex incidence
Shigella flexneri, salmonella typhi/enteritidis, yersinia, campylobacter, chlamydia trachomaatis
What is the triad of reactive arthritis?
Urethritis
Conjunctivitis/anterior uveitis
Arthritis - asymmetrical, lower limbs
Also dactylitis, circinate balanitis, keratoderma blenorrrhagica
What is the prognosis of reactive arthritis?
Symptoms last 4-6 months
25% have recurrent episodes, 10% chronic disease
In gout, where are the urate crystals deposited?
Superficial portions of the articular cartilage
What is the most common cause of gout?
Decreased excretion of uric acid - diuretics, CKD, lead toxicity
What are other causes of gout?
Increased production of uric acid - myeloproliferative disorder, cytotoxic drugs, severe psoriasis
Lesch-Nyhan syndrome
What are the X-Ray features of gout?
Joint effusion "Punched out" erosions with sclerotic margins in a juxta-articular distribution, often with overhanging edges Eccentric erosions No periarticular osteopenia Soft tissue tophi
What is the double contour sign in gout?
Hyperechoic irregular band over the superficial margin of the joint cartilage, produce by deposition of monosodium urate crystals on the surface of the hyaline cartilage
Where do calcium pyrophosphate crystals deposit in pseudogout?
The middle layer of the hyaline cartilage, parallel to the bony cortex as a hyper-echoic irregular line embedded in the cartilage (with a normal hyaline cartilage surface)
What are risk factors for pseudogout if it develops at a younger age?
Haemochromatosis Hyperparathyroidism Low magnesium Low phosphate Acromegaly Wilson's disease
What is seen on joint aspiration in pseudogout?
Weakly positive birefringent rhomboid shaped crystals
What are the 3 types of systemic sclerosis?
Limited cutaneous
Diffuse cutaneous
Scleroderma
What are the features of limited cutaneous systemic sclerosis?
Raynaud’s may be first sign
Scleroderma of face an distal limbs
Subtype: CREST syndrome (calcinosis, Raynaud’s, oesophageal dysmotility, sclerodactyly, telangiectasia)
What are the features of diffuse cutaneous systemic sclerosis?
Scleroderma of trunk and proximal limbs
Respiratory (ILD and PAH) involvement, renal disease
Which antibodies are associated with systemic sclerosis?
Limited cutaneous: ACA
Diffuse cutaneous: Anti-Scl-70
Both: ANA in 90%, RF in 30%
What are the features of antiphospholipid syndrome?
Venous and arterial thombosis
Recurrent foetal loss
Thrombocytopenia
Livedo reticularis
Why is APTT high in APS?
Ex vivo reaction of the lupus anticoagulant autoantibodies with phospholipids involved in the coagulation cascade
What is the treatment of antiphospholipid syndrome?
Primary thromboprophylaxis - low dose aspirin
Secondary thromboprophylaxis - lifelong warfarin, target INR 2-3
Recurrent VTE on warfarin - add low dose aspirin, target INR 3-4