Crystal Arthritis Flashcards
what is gout?
inflammation in the joint triggered by uric acid crystals
who more commonly gets gout, F or M?
M
rate of gout for F starts to increase after menopause
what causes uric acid crystal deposition?
hyperuricaemia
encouraged by low temperature of synovial fluid
what are the 3 main reasons for hyperuricaemia?
excess consumption
over production
under excretion
why can psoriasis cause hyperuricaemia?
causes increased urate production
why can chronic renal impairment cause hyperuricaemia?
causes reduced urate excretion
why can a high alcohol intake cause hyperuricamia?
causes increased urate production
why can a high red meat or seafood intake cause hyperuricaemia?
causes increased urate production
why do diuretics cause hyperthyroidisim?
cause reduced urate production
in acute gout, usually only one joint is involved, which are the most likely joints?
- first metatarsalpharyngel (MTP)
- ankle
- knee
compare rates of acute gout settling- treatment or no treatment?
no treatment- 10 days
treatment- 3 days
compare the serum urate levels of acute to gout to chronic gout?
acute gout- urate levels may be normal
chronic gout- urate levels are high
compare acute gout to chronic gout in terms of the number of joints involved
acute- only one joint involved
chronic- multiple joints
why can chronic gout cause renal impairement?
uric acid crystallisation can occur in the glomeruli and damage the kidneys
what is the gold standard way to diagnose gout?
polarising microscopy of synovial fluid
what are the 3 main medications used in the treatment of acute gout?
NSAIDs
Colchicine
Steroids
what treatments are used in the prophylaxis of recurring gout?
allopurinol febuxostat uricosurics (2-4 weeks after acute attack) initiially treat acute attack with NSAID, colchine or steroids
what crystals are deposited in joints in pseudogout?
calcium pyrophosphate
compare the shape of calcium pyrophosphate crystals to uric acid crystals?
calcium pyrophosphae- blunt
uric acid crystals- long and sharp
what is the treatment of acute pseudogout?
NSAIDs
Colchicine
Steroids
Rehydration
what is the treatment of chronic pseudogout?
no long term treatment, treat acute episodes
what is milwaukee shoulder?
destructive shoulder arthropathy due to hydroxyapatite crystal deposition in/around joint
what is the treatment of hydroxyapatite crystal deposition?
NSAIDs
intra-articula steroid injecionts
physiotherapy (to mobilise joint)
partial or total arthroplasty
what nucleotides are broken down to form uric acid?
purines (adenine and guanine)
what is the name of gout affecting the first metatarsalphalangeal (MTP) joint?
podagra
how does gout present?
intensely painful, red, hot swollen joint
what diagnosis looks similar to gout but is much more serious?
septic arthritis
what are gout tophi?
painless white accumulations of uric acid which occasionally erupt through the skin near a joint
what do uric acid crystals display under polarised microscopy?
negative birefringence
what is chondrocalcinosis?
calcium pyrophosphate deposition in cartilage and other soft tissues
(no acute inflammation)
what are the 2 conditions that can occur in calcium pyrophosphate deposition disease?
pseudogout
chondrocalcinosis
what enzyme do allopurinol and febuxostat work on?
and what is the mechanism?
xanthine oxidase
they are xanthine oxidase inhibitors so prevent xanthine being converted to uric acid
why should patients on azathioprine not be prescribed allopurinol?
interaction causing irreversible bone marrow failure
what should you do when giving allopurinol to a patient with renal impairment?
lower dose of allopurinol
when is febuxostat used over allopurinol in the prophylaxis of gout?
in those who cannot tolerate allopurinol
what patients should febuxostat be used in caution?
patients with ischaemic heart disease
