Gout

1. Gout

2. What are the risk factors for gout? • Hyperuricemia • Male sex • Older age • Obesity • Diet high in animal sources of purines (red meat, shellfish) • Alcohol and high-fructose corn syrup-sweetened drinks • Medications (thiazide or loop diuretics, cyclosporine) • Renal insufficiency • Organ transplantation • Genetic risk factors

3. What comorbid diseases are associated with gout? • Renal insufficiency • Psoriasis • Hypertension • Diabetes • Hyperlipidemia • Metabolic syndrome • Cardiovascular disease

4. Are there effective strategies for prevention? • Dietary changes and weight loss • May lower serum urate levels • Therapy not indicated for asymptomatic hyperuricemia • Not proven to have adverse consequences • Long-term ULT may carry long-term risks • Treatment guidelines may change if there are sufficient evidence to show that hyperuricemia confers increased renal or cardiovascular disease risk

5. CLINICAL BOTTOM LINE: Prevention and Screening... • Risk factors • Hyperuricemia • Age, sex, obesity, renal insufficiency, diuretic use, diet • Genetic variants may increase risk • Common comorbidities • Diabetes, CVD, renal impairment, hypertension, metabolic syndrome, hyperlipidemia • Therapy not recommended for asymptomatic hyperuricemia • Lifestyle modifications appropriate in patients with only 1 gout attack and no other indications for ULT

6. What symptoms and physical examination findings suggest gout? • Acute onset joint pain at night • Swollen, erythematous, warm, exquisitely painful joint • Maximum pain within 24 h and resolves within 2 weeks • First Metatarsophalangeal joint most commonly involved • MSU crystals tend to form in previously diseased joints • With longer-disease duration and unabated hyperuricemia, persistent inflammation may occur • Urate deposition may be evident as subcutaneous nodules • Imaging may reveal tophaceous deposits

7. What tests can diagnose gout? • Examination of synovial fluid or tophus aspirate • Polarized microscopy, cell count, culture • MSU crystals in synovial fluid or tophus aspiration required to establish diagnosis • Other useful tests in diagnosing gout • Serum urate level • CBC with differential (if considering septic arthritis) • Radiography (to rule out other causes or to look for gouty erosions when symptoms are long-standing) • US or DECT imaging (to identify findings specific for gout)

8. What is the value of imaging? • Plain radiography • Show gout-related bone erosion, tophi • Show conditions coexisting with or confused for gout • Ultrasonography • Facilitate joint aspiration • Identify articular urate deposition, tophi, inflammation • DECT (not yet used in practice) • Differentiate calcium from urate • MRI (not routinely used in practice) • Show joint inflammation, damage, tophi—but cannot necessarily distinguish gout from CPP arthritis

9. What are the differential diagnoses? • Calcium pyrophosphate deposition • Septic arthritis • Cellulitis • Rheumatoid arthritis • Osteoarthritis • Psoriatic arthritis • Sarcoidosis

10. What classification criteria are used for gout in research studies? • MSU in synovial fluid or tophus aspiration is sufficient for classification as gout • ACR/EULAR criteria encompass following parameters: • Pattern of joint involvement during symptomatic episodes • Characteristics of symptomatic episodes • Time course of symptomatic episodes • Clinical evidence of tophus • Highest level of serum urate ever recorded off-treatment • MSU results of synovial fluid analysis • Imaging evidence of urate deposition • Imaging evidence of gout-related joint damage

11. CLINICAL BOTTOM LINE: Diagnosis... • MSU crystals in synovial fluid or tophus confirm diagnosis • Joint pain and hyperuricemia alone do not • Aspirate synovial fluid from joint or suspected tophus • Serum urate measurement is helpful but not diagnostic • Examine aspirated material under polarizing microscopy to differentiate gout from CPP-related arthritis • Examine synovial fluid cultures and clinical features to differentiate from septic arthritis • Radiography and ultrasonography: help identify other joint conditions and gout-specific features

12. When should clinicians consider hospitalizing a patient with gout? • Gout attacks are one of the most painful conditions • Hospitalization is warranted if: • Patient cannot care for self at home • Septic arthritis is a concern (to diagnose definitively and administer antibiotics promptly to prevent joint damage) • To monitor response to therapy, repeated synovial fluid analysis may be warranted for cell count and culture

13. What is the role of nonpharmacologic therapy in managing patients who already have gout? • Adjunct to long-term pharmacologic management • Most patients with gout require pharmacologic therapy • Lifestyle changes may help reduce serum urate levels • Reduce consumption of dietary contributors • Weight loss • Adequate hydration • Don’t blame patients for gout • Renal urate underexcretion, with genetic underpinnings, is the major contributor

14. What is the role of pharmacologic therapy? • Most patients require pharmacologic therapy • Urate-lowering therapy: cornerstone of management • Prophylaxis: when starting ULT to mitigate expected increased risk for attacks during initial phase • Anti-inflammatory therapy: for gout attacks • Indications for urate-lowering therapy • Frequent attacks (≥2 per year) • Tophus on clinical examination or imaging study • Chronic kidney disease stage ≥2 • Past urolithiasis (of any type)

15. When should clinicians consider consulting a specialist? • If a septic joint is suspected • To aid with joint aspiration • When gout is difficult to manage • First-line monotherapy insufficient • Contraindication or caution for gout attack management • Features may be related to other forms of arthritis • Patient is young, with possible inherited metabolic disease • Surgery is not indicated except when tophi pose an urgent function- or organ-threatening risk

16. CLINICAL BOTTOM LINE: Treatment... • Pharamcologic treatment • ULT if the patient has a clinical indication • Prophylaxis when initiating ULT • Anti-inflammatory therapy for gout attacks • Patient education • Causes of gout • Management of hyperuricemia • Adjunctive lifestyle modifications • Hospitalization warranted when gout-related pain and functional limitations cannot be controlled