Crystal arthropathies Flashcards
which type of crystal arthropathy has a Tx?
gout
what is the etiology of gout?
men and postmenopausal women, acute inflammatory, complicated by DM, HTN, heart disease
what are the clinical features of gout?
- hyperuricemia (underexcretion)
- acute monoarticular arthritis (over Dx)
- acute polyarticular arthritis (under Dx)
- tophi and chronic arthritis
- nephrolithiasis
where is gout most likely to happen? why?
big toe; high hydrostatic pressure
what are risk factors for gout?
obesity, seafood/meat, ETOH, high fructose corn syrup
what is the main cause of gout?
primary underexcretion (highest incidence in Mauis)
what is the most common cause of secondary underexcretion in gout?
chronic renal failure
where is uric acid excreted?
2/3 kidneys, 1/3 stomach
____is necessary but not sufficient for gout
hyperuricemia
what is the most likely DDx for gout?
septic arthritis
what substance is implicated in pseudogout?
calcium pyrophosphate
what condition is likely to result in pseudogout?
hereditary hemochromatosis
should Dx of gout be based on serum uric acid alone? why?
no; serum rates decreased during acute flare (urate crystals not measured in serum urate, acute inflammation lowers urate)
when should serum urate be measured?
2wks after acute attack
MSU crystals indicate___
CPPD crystals indicate___
gout (negative birefringement)
pseudogout (positive birefringement)
what are the criteria on the score system for gout?
- male
- previous arthritis attack
- onset in <1day
- joint redness
- MTP1 involved
- HTN or CVD
- serum uric acid >350ul
what XR features are found in gout?
erosion w overhanging edges, cloudy XR, rate bite lesions
what tests are used to pick up MSU deposits in gout?
DECT or GSI-CT
what are the goals of Tx for gout?
- prevent attacks
- prevent urate grystal deposition
- prevent complications (amputation)
- prevent comorbidities (CV, metabolic)
what is the goal of acute Tx for gout?
exclude septic arthritis, suppress pain and inflammation
what concentration of serum urate is the target in chronic gout Tx?
<360ul (avoid progression and complication)
what are examples of uric acid lowering agents?
allopurinol, febuxostat, probenecid
what can cause secondary overproduction in gout?
lyphoproliferative diseases, hemolytic anemia, psoriasis
what usually precedes gout attacks?
intra-articular tophi
what are the features of chronic gout?
> 2 flares/yr, tophi, uric acid overproduced, Hx kidney stones, severe polyarticular/persistent flares, chronic synovitis
