Rheumatology handbook Flashcards
What is the clinical features of gouty arthritis?
Acute gout (monoarticular, polyarticular)
Chronic tophaceous gout
Uric acid calculi
Gouty nephropathy
What is the dx of gout?
Definitive gout: intracellular negative birefringement urate crystal on joint fluid microscopy
Presumed gout: classical history of episodic acute arthritis rapidly resolved with NSAID (or colchicine) + history of hyperuricemia
What is the management of acute gouty arthritis?
1. NSAID/COX2 inhibitors (Note! Check patient’s drug allergy)
High dose, tapering over 5 days, reduce dose in renal impairment: a) indomethacin 50 mg TDS25 mg TDS25 mg BD
b) naprosyn 500 mg STAT250 mg TDS250 mg BD
c) Celecoxib 200 mg BD (if high GI risk)
2. Colchicine
0.5 mg TDS for 1–2 days (stop if nausea/diarrhoea) Renal impairment – caution and reduce frequency Not recommend Q1HQ2H for 10 doses regime
3. Corticosteroid
a)** Intra-articular steroid** injection after septic arthritis ruled out
b) Prednisolone 20 to 40 mg daily within 1 week, rapid tapering
(consider for patients with NSAID or colchicine contraindications, or renal failure)
What is the urate lowering therapy for gout?
1. Xanthine oxidase inhibitors (Do NOT use with azathioprine!)
a. Allopurinol (usual dose 300 mg daily)
Start with low dose 100 mg daily; increase weekly to your target dosage; inform patients to stop if skin reaction (~5%) and seek medical attention early
Further reduce dose in renal impairment, step up slowly
Start allopurinol only when acute gout has subsided
Prophylaxis: add regular colchicine 0.5 mg daily or bd, or
NSAID, for 3 to 6 months, to prevent acute gout attacks
Titrate dose to target serum uric acid < 0.36 mmol/L
FDA approved maximal dose is 800 mg daily
Severe cutaneous adverse reactions are associated with
HLA B*5801 in Han Chinese
b. Febuxostat – a new non-purine selective xanthine oxidase inhibitor
Alternative for patients with allopurinol cutaneous adverse reaction
Usual dose 40 mg to 80 mg daily
Caution in patients with high cardiovascular thromboembolic risks
2. Uricosuric drugs
Probenecid 250 mg BD to 1000 mg TDS
(Contraindications: moderate renal impairment, urate renal stone, tophaceous gout, and high 24-hour urine uric acid excretion) Benzbromarone – licensed in HK but not under HA formulary Sulfinpyrazone – not licensed in HK
3. Uricase
Rasburicase, a recombinant urate-oxidase enzyme, is for pre- chemotherapy prevention of acute tumour lysis syndrome. Caution in G6PD deficiency.
What is the 2010 ACR/EULAR classification criteria for RA?
What are the investigations for RA?
ESR and C-reactive protein (CRP)
RF (sensitivity ~70%)
Anti-cyclic citrullinated peptide antibody (anti-CCP) – highly
specific for RA, helpful in undetermined situations
Plain X-ray of the hands and feet for erosion
MRI or USG may be useful for detecting early bony erosion
What is the DMARD management of RA?
- Conventional DMARDs
Start DMARDs early! All take time to act.
Usually start with methotrexate monotherapy, but step-up combination may be considered early in patient with severe disease
Titrate up to optimal doses according to RA disease activity
Switch or add-on another DMARD promptly if target not met
Counsel patients on DMARD effects and side effects and their slow action
Anchor drug is methotrexate
Other examples: sulphasalazine, hydroxychloroquine, leflunomide, low dose prednisolone (less than 10 mg/day), less commonly used are cyclosporin A, tacrolimus, azathioprine, intramuscular gold - Biologics
E.g. anti-TNF (Etanercept, Adalimumab, Infliximab, Golimumab, Certolizumab), IL-6 receptor blocker (Tocilizumab), co- stimulation molecule blocker (Abatacept), anti-CD 20 (Rituximab)
What is the ASAS criteria for axial spondyloarthritis (SpA)?
a. Imaging evidence of sacroiliitis (XR, MRI or CT) plus one SpA features*
b. HLA-B27 positivity plus 2 other SpA features*
SpA features:
Inflammatory back pain age of onset < 40 Arthritis
Enthesitis
Psoriasis
Uveitis
Dactylitis
Crohn’s/colitis
Good response to NSAIDs
Family history for SpA
Elevated C-reactive protein (CRP) HLA-B27
How to measure decreased spinal mobility in AS?
a. Modified Schober test – spinal forward bending (excursion of two points: PSIS level and 10 cm above; normal excursion > 5 cm).
b. Note: finger floor distance may be apparently normal when good hips flexion compensates limited spinal flexion
c. Occiput-to-wall: normal 0 cm
d. Tragus-to-wall: normal < 14 cm
e. Chest expansion
f. Cervical rotation
g. Intermalleolar distance
What are the investigations for ankylosing spondylitis?
a. XR sacroiliac joints and spine
b. MRI SI joints in doubtful cases
c. HLA-B27 (role refers to ASAS criteria)
What is the diagnostic criteria for psoriatic arthritis?
What are the features distinguishing PsA from RA?
Presenceofpsoriasis
- Hidden lesions common, e.g. scalp, hairline, behind the ear and
inside ear cannel, guttate lesions on back, under the breasts,
around umbilicus, around the perineum or even natal cleft Nail dystrophy
- Onycholysis, pitting, ridging, etc
Distal phalangeal joint involvement
Spondylitisorsacroiliitis
Enthesitis(inflammationofjunctionofligament,tendonorjoint
capsule to bone)
Dactylitis
What is the ACR criteria for classification of SLE?
> 4 criteria
1. Malar rash
2. Discoid rash
3. Photosensitivity
4. Oral ulcers
5. Arthritis
6. Serositis (pericarditis, peritonitis, pleuritis)
7. Renal disease (proteinuria > 0.5 g/day, or +++ by dipstick, or
cellular casts)
8. Neurological (seizure, or psychosis)
9. Haematological (haemolytic anaemia, or leucopenia < 4×109/L,
lymphopenia < 1.5×109/L, on two or more occasions, or
thrombocytopenia < 100×109/L)
10. Immunological (anti-dsDNA, or anti-Sm, or false +ve VDRL for
more than 6 months, or the presence of the antiphospholipid
antibodies)
11. Positive anti-nuclear antibody (ANA)
What is the immunologic criteria for SLE?
- ANA above laboratory reference range
- Anti-dsDNA above laboratory reference range (except ELISA: twice
above laboratory reference range) 3. Anti-Sm - Antiphospholipid antibody: e.g. lupus anticoagulant, false-positive test for syphilis, anticardiolipin antibody (at least twice normal or medium-high titre), anti-β2 glycoprotein 1 antibody
- Low complement: e.g. low C3, low C4, low CH50
- Direct Coombs test in absence of haemolytic anaemia
Anti ENA antibodies
Anti: Ro causing congenital heart block so prenatal counselling and UV light protection is advised
Anti ENA antibodies seldom sero-convert and repeating tests is not necessary
Antiphospholipid antibodies
Lupus anticoagulant, anti-cardiolipin (aCL) antibody associated with thrombocytopenia, livedo reticularis, valvular heart lesions, recurrent miscarriages, arterial and venous thrombosis
Twice positive tests 12 weeks apart necessary for dx of antiphospholipid syndrome.
How do we monitor disease activity of SLE?
Clinical assessment (signs and symptoms of disease flares)
Serology: C3 and C4 level, anti-dsDNA titre
ANA titer does not correlate with disease activity and is not reliable for disease monitoring. No need to repeat ANA if it is already positive.
CRP is usually not elevated with active SLE. An elevated CRP in SLE may indicate infection, persistent synovitis/arthritis, serositis. Infection has always to be considered before augmentation of immunosuppressive therapy.
What is the treatment of SLE?
General: Patient education and counselling, sun-screening (avoid strong sunlight, frequent application of SPF 15+ sun lotion), screening and treatment of cardiovascular risk factors and osteoporosis, vaccination and infection prevention, early recognition and prompt treatment
Hydroxychloroquine should be considered for every lupus patient:
Overall stabilizing SLE
Decreases infection, some anti-thrombotic and lipid lowering effect Stabilises pregnant SLE patients and improves foetal outcome
Recommend < 5 mg/kg/day
Mild SLE manifestations
NSAIDs – arthritis, serositis, fever
Hydroxychloroquine – arthritis, skin lupus
Methotrexate – persistent and refractory arthritis and skin
Topical steroid – skin lupus
Smalltomoderatedosesofprednisolone–fever,systemicupset,mild
cytopenias, more severe serositis and skin lupus
Azathioprine – haematological, mild renal disease, steroid sparing
Belimumab (Benlysta) – as an alternative for arthritis, skin lupus,
serositis, haematological