Rheumatology Flashcards
(162 cards)
Test to distinguish gout form pseudogout
polarised red light of joint aspirate
Test result for gout on joint aspirate
monosodium urate crystals are negatively birefringent in polarised light– they will appear a needle shaped crystals.
Test results for pseudo gout on joint aspirate
Calcium pyrophosphate crystals are positively birefringent in polarised light– they will appear as rhomboid shapes
Drugs which increase risk of gout
Thiazide diuretics
Chronic symptoms or complications of gout
Tophi - urate deposits in skin esp pinna of ear. White lesions, feel chalky, proportional to severity of disease.
Nephrolithiasis.
Secondary osteoarthritis
Treatment of gout
Acute: NSAID, colchicine, prednisolone if renal impairment. Rest, elevate joint, ice packs.
Chronic: Allopurinol of more than 1 attack in a year, evidence of tophi or nephroliathsis. Also can low dose aspirin and lifestyle advice to change diet.
Pharmacology for allopurinol and monitoring.
Inhibits the enzyme xanthene oxidase.
Monitor serum urate level every 3 weeks to check effectiveness. Target for uric acid < 300
Check kidney functions.
Titrate slow and low. Do not start immediately after acute attack as can precipitate flare-up. Wait 3 weeks.
X-ray of gout
‘punched-out’ periarticular erosions.
Flecked calcifications.
Normal joint space.
Soft tissue swelling.
Most common area for gout and pseudogout
Gout = first metatarsophalangeal joint Pseudogout = knee
X-ray for pseudogout
Cartilage calcification/Chondrocalcinosis - white horizontal lines in cartilage.
x-ray for OA
Osteophytes from new born formation.
Joint space narrowing.
Bone cysts
Subchondral sclerosis.
x-ray for RA
Soft tissue swelling.
Loss of joint space.
Joint deformity and erosions.
Juxta-articular osteopenia.
Use of biologics in RA
If RA does not respond to 2 DMARDs, DAS28 >5.1
DAS28
Disease activity score in rheumatoid arthritis of 28 joints.
One criteria for starting anti-TNF is DAS28 >5.1.
3 examples of TNF alpha inhibitors
Infliximab, etanercept, adalimumab
Contraindications for TNF alpha inhibitors
pregnancy, breast feeding, severe HF, haematological malignancy, active infection.
Common side effects of TNF alpha inhibitors
Worsening HF, reactivation of TB, fever, injection site swelling.
Risk factors for septic arthritis
prosthetic joint, IVDU, immunosuppressant drugs e.g. chemo, steroids, immunocompromised e.g. HIV/AIDS, DM, RA, OA, unprotected sex.
Common organism for septic arthritis
S.aureus.
Risk factors for gout
High purine diet e.g. red meat, beer, seafood. CKD HTN Tumour lysis syndrome. Diuretics.
Triggers for gout
Infection, trauma/injury, dehydration, alcohol binge, surgery.
Blood tests in pseudogout.
High Ca Low Mg Low phosphate High iron Low parathyroid.
Gene associated with seronegative arthropathies
HLA B27
Diseases with a positive rheumatoid factor result
Sjogren's syndrome Felty's syndrome Rheumatoid arthritis Mixed connective tissue disease SLE in <40% Systemic sclerosis in 30%