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GOUT. Wayne Blount, MD, MPH Professor, Emory Univ. S.O.M. OBJECTIVES. Identify diagnostic criteria for gout Identify 3 treatment goals for gout Name the agents used to treat the acute flares of gout and the chronic disease of gout. Why Worry About Gout ?. Prevalence increasing
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GOUT Wayne Blount, MD, MPH Professor, Emory Univ. S.O.M.
OBJECTIVES • Identify diagnostic criteria for gout • Identify 3 treatment goals for gout • Name the agents used to treat the acute flares of gout and the chronic disease of gout
Why Worry About Gout ? • Prevalence increasing • May be signal for unrecognized comorbidities : ( Not to point of searching) Obesity (Duh!) Metabolic syndrome DM HTN CV disease Renal disease
URATE, HYPERURICEMIA & GOUT • Urate: end product of purine metabolism • Hyperuricemia: serum urate > urate solubility (> 6.8 mg/dl) • Gout: deposition of monosodium urate crystals in tissues
HYPERURICEMIA & GOUT • Hyperuricemia caused by Overproduction Underexcretion • No Gout w/o crystal deposition
THE GOUT CASCADE • Urate • Oevrproduction Underexcretion • Hyperuricemia • ________________________________________ • Silent Gout Renal Associated • Tissue manifestations CV events & • Deposition mortality
GOUT: A Chronic Disease of 4 stages • Asymptomatic hyperuricemia • Acute Flares of crystallization • Intervals between flares • Advanced Gout & Complications
ACUTE GOUTY FLARES • Abrupt onset of severe joint inflammation, often nocturnal; Warmth, swelling, erythema, & pain; Possibly fever • Untreated? Resolves in 3-10 days • 90% 1st attacks are monoarticular • 50% are podagra
SITES OF ACUTE FLARES • 90% of gout patients eventually have podagra : 1st MTP joint
Sites • Can occur in other joints, bursa & tendons
INTERVALS SANS FLARES • Asymptomatic • If untreated, may advance • Intervals may shorten • Crystals in asx joints • Body urate stores increase
FLARE INTERVALS • Silent tissue deposition & Hidden Damage
ADVANCED GOUT • Chronic Arthritis • X-ray Changes • Tophi Develop • Acute Flares continue
ADVANCED GOUT • Chronic Arthritis • Polyarticular acute flares with upper extremities more involved
TOPHI • Solid urate deposits in tissues
TOPHI • Irregular & destructive
TOPHI RISK FACTORS • Long duration of hyperuricemia • Higher serum urate • Long periods of active, untreated gout
DIAGNOSING GOUT • Hx & P.E. • Synovial fluid analysis • Not Serum Urate
SERUM URATE LEVELS • Not reliable • May be normal with flares • May be high with joint Sx from other causes
GOUT RISK FACTORS • Male • Postmenopausal female • Older • Hypertension • Pharmaceuticals: Diuretics, ASA, cyclosporine
GOUT RISK FACTORS • Transplant • Alcohol intake Highest with beer Not increased with wine • High BMI (obesity) • Diet high in meat & seafood
SYNOVIAL FLUID ANALYSIS (Polarized Light Microscopy) • The Gold standard • Crystals intracellular during attacks • Needle & rod shapes • Strong negative birefringence
DIFFERENTIAL DIAGNOSIS • Pseudogout: Chondrocalcinosis, CPPD • Psoriatic Arthritis • Osteoarthritis • Rheumatoid arthritis • Septic arthritis • Cellulitis
Gout vs. CPPD • Similar Acute attacks • Different crystals under Micro; Rhomboid, irregular in CPPD
RA vs Gout • Both have polyarticular, symmetric arthritis • Tophi can be mistaken for RA nodules
REDNECK MEDICAL TERMS • “BENIGN” : WHAT YOU BE AFTER YOU BE EIGHT
TREATMENT GOALS • Rapidly end acute flares Protect against future flares Reduce chance of crystal inflammation • Prevent disease progression Lower serum urate to deplete total body urate pool Correct metabolic cause
ENDING ACUTE FLARES • Control inflammation & pain & resolve the flare • Not a cure • Crystals remain in joints • Don’t try to lower serum urate during a flare • Choice of med not as critical as alacrity & duration EBM
Acute Flare Med Choices • NSAIDS • Colchicine • Corticosteroids
MED Considerations • NSAIDS : Interaction with warfarin Contraindicated in: Renal disease PUD GI bleeders ASA-induced RAD
MED Considerations • Colchicine : Not as effective “late” in flare Drug interaction : Statins, Macrolides, Cyclosporine Contraindicated in dialysis pt.s Cautious use in : renal or liver dysfunction; active infection, age > 70
MED Considerations • Corticosteroids : Worse glycemic control May need to use mod-high doses
TREATMENT GOALS • Rapidly end acute flares Protect against future flares Reduce chance of crystal inflammation • Prevent disease progression Lower serum urate to deplete total body urate pool Correct metabolic cause
PROTECTION VS. FUTURE FLARES • Colchicine : 0.5-1.0 mg/day • Low-dose NSAIDS • Both decrease freq & severity of flares • Prevent flares with start of urate-lowering RX Best with 6 mos of concommitant RX EBM • Won’t stop destructive aspects of gout
TREATMENT GOALS • Rapidly end acute flares Protect against future flares Reduce chance of crystal inflammation • Prevent disease progression Lower serum urate to deplete total body urate pool Correct metabolic cause
PREVENT DISEASE PROGRESSION • Lower urate to < 6 mg/dl : Depletes Total body urate pool Deposited crystals EBM • RX is lifelong & continuous • MED choices : Uricosuric agents Xanthine oxidase inhibitor
URICOSURIC AGENTS • Probenecid, (Losartan & fenofibrate for mild disease) • Increased secretion of urate into urine • Reverses most common physiologic abnormality in gout ( 90% pt.s are underexcretors)
XANTHINE OXIDASE INHIBITOR • Allopurinol : • Blocks conversion of hypoxanthine to uric acid • Effective in overproducers • May be effective in underexcretors • Can work in pt.s with renal insufficiency
WHICH AGENT ? Allopurinol Uricosuric Issue in renal disease X X Drug interactions X X Potentially fatal hypersen- sitivity syndrome X Risk of nephrolithiasis X Mutiple daily dosing X
WHICH AGENT • Base choice on above considerations & whether pt is an overproducer or underexcretor : Need to get a 24-hr. urine for urate excretion: < 700 --- underexcretor (uricosuric) > 700 --- overproducer (allopurinol)
NEW AGENTS • RX gaps : • Can’t always get urate < 6 • Allergies • Drug interactions • Allopurinol intolerance • Worse Renal disease
URICASE ENZYMES(Stay Tuned) • Catabolize urate to allantoin: More soluble, excretable form • Currently approved for hypoeruricemia in tumor lysis syndrome • Some concerns: fatal immunogenicity & unknown long-term effects