Crystal Arthropathies Flashcards
what causes Gout
deposition of urate crystals in a joint
what causes urate crystal deposition in joints
high serum uric acid levels (hyperuricaemia)
what is uric acid the final compound of
breakdown of purines in DNA metabolism (adenine and guanine)
what can cause hyperuricaemia
renal underexcretion or excessive intake of alcohol, red meat and seafood
what can cause renal underexcretion
diuretics or renal failure
what can trigger uric crystal precipitation in joints
dehydration, trauma or surgery
what is the common location for gout
first MTP joint (podagra), ankle to knee
how does gout present
intensely painful, red, hot and swollen joint
what is an important differential for gout
septic arthritis
how long does it usually take for symptoms to die down if gout is untreated
7-10 days
what are gouty tophi
painless white accumulations of uric acid occurring in the soft tissues and can erupt through the skin
what can chronic gout cause
destructive erosive arthritis
how is a definitive diagnosis made
analysing a sample of synovial fluid with polarised microscopy (also gram stain and culture to rule out infection)
how do uric acid crystals show
needle shaped and negative birefringement (change from yellow to blue when lined across the direction of polarisation)
what is the treatment for acute attacks
NSAID’s, corticosteroids, opioid analgesics and colchicine if patients can’t tolerate NSAID’s
what is the treatment for recurrent attacks or gouty tophi
allopurinol or other urate lowering therapies (should not be started until an acute flare has settled or can cause further flare)
what crystals cause pseudogout
calcium pyrophosphate crystals
what is the term chondrocalcinosis used
when calcium pyrophosphate deposition occurs in cartilage and other soft tissues in the absence of inflammation
what category do both pseudogout and chondrocalcinosis come under
calcium pyrophosphate deposition disease (CPPD)
where does CPPD tend to affect
knee, wrist and ankle
what conditions can CPPD occur with
hyperparathyroidism, hypothyroidism, renal osteodystrophy, haemochromatosis and Wilson’s disease and OA sometimes
what can CPPD lead to
osteoarthritis change
what is the treatment for acute CPPD
NSAID’s, corticosteroids (systemic and extra-articular) and colchicine
are there any medications to prevent recurrence of CPPD
no
