HYHO - Gout and Psuedogout Flashcards
Which nitrogen bases build up in gout? What sources are there for these?
Purines adenine and guanine produce uric acids in body.
Diet and NT synthesis/metabolism
What is the degradation pathway for purines?
Inosine -> hypoxanthine -> xanthine -> uric acid
Xanthine oxidase helps w last two steps
Excreted from kidneys (70%) and gut
Definition of gout
Intermittent, painful, inflammatory joint attack responding to uric acid crystals due to hyperuricemia
Risk factors for gout
Male Age (older) Obesity HTN Hyperlipidemia CV disease CKD Medications Diet Lead exposure
What two processes can cause hyperuricemia?
Overproduction of UA - hepatic metabolism or cell turnover
Under excretion of UA from kidneys or gut - main cause
Clinical presentation of gout
Acute onset of joint pain, w max pain in 1st 24hrs
Often begin over night in acute flares
Joint is swollen, red, warm, and hurts
What are the most commonly affected joints in gout?
1st MTP joint, knee joints, ankle joints
What are provoking factors of gout?
ETOH consumption
Trauma
Inflammatory states
Dehydration
What are gouty tophi?
Uric acid deposition w/in tissue
What is the definitive test for gout?
Arthrocentesis of affected joint
send for cell count, culture, and gram stain
Use polarized light microscopy to look for monosodium urate crystals - needle shaped, negatively birfringent crystals
Other than arthrocentesis, what tests should you order if gout is suspected?
Serum uric acid level
CBC w dif - look for left shift to rule out septic arthritis
X-ray isn’t helpful if acute, but could do for chornic to look for bony erosions
Synovial fluid that is characteristic of gout?
WBCs is between 10,000-50,000/ mcg
infectious arthritis also has high WBC, but will use gram stain and fluid culture to rule out
Tx of gout in patients with CKD
Be careful using NSAIDs and colchicine
Intra-articular injection or oral steroid are usually preferred
Acute gouty flare treatment
NSAIDS
Colchicine - inhibits cytoskeletal fxn of neutrophils
Glucocorticoids -preferred for CKD
Chronic gout tx
Xanthine oxidase inhibitors - wait two weeks after flare. allopurinol and febuxostate
Uricosuric agents to inhibit reabsorption of UA in PCT. Probenecid and Lesinuard
Uricase - converts UA to highly soluble allantonin
Goal uric acid for patients with tophi and without?
With tophi - <6 mg/dl
W/o - <5 mg/dl
Uricosuric agents
Probenecid and lesinurad
Xanthine oxidase inhibitors
Allopurinol and febuxostate
Prevention of gout
Avoid factors that contribute, like red meat, seafood, alcohol, high fructose corn syrup
Pseudogout (Calcium Pyrophosphate Deposition)
Deposition of CPP crystal in and on cartilaginous surfaces can provoke acute inflammatory arthritis similar to gout
Epidemiology of CPPD
> 60 tears
Osteoarthritis
Metabolic diseases - hyperparathyroidism, hemochromatosis, hypophosphatasia, hypomagnesemia
Pathophysiology of CPPD
not really known, but probs pyrophosphate made by chondrocytes precipitates calcium forming CPP crystals
Clinical presentation
Typically presents as monoarticular or oligoarticular arthritis.
Swollen, warn, painful
Knee and wrist joints, but not commonly the 1st MTP joint
Can last for weeks or months! Dif from acute gout
What are provoking factors for pseudogout?
Surgery or acute illness
