Snapshot A 55-year-old woman presents to the emergency department with acute pain in the left proximal interphalangeal (PIP) joint of the second digit. She reports that the pain is excruciating and has happened once a few years ago but self-resolved over the course of 2 weeks. She states that she recently increased her alcohol and red meat consumption and was recently started on hydrochlorothiazide. On physical exam the PIP joint is swollen, erythematous, warm, and tender to palpation. Preparations are made for an arthrocentesis to be performed. Introduction Clinical definition deposition of monosodium urate crystals leading to a crystal-induced arthropathy Epidemiology Demographics more common in men and the elderly Risk factors conditions that increase serum urate levels (hyperuricemia) Etiology Hyperuricemia defined as a serum urate level > 6.8 mg/dL causes of hyperuricemia include dietary habits login to view 3 more bullets medications login to view 5 more bullets disorders of urate overproduction login to view 5 more bullets Pathogenesis purine catabolism results in uric acid production factors that influence serum uric acid level include login to view 3 more bullets conditions that increase the serum uric acid concentration increases the risk of crystal formation deposition of uric acid crystals lead to an inflammatory response login to view 1 more bullet Presentation Symptoms acute gout extreme pain of the affected joint (e.g., foot or ankle) chronic tophaceous gout stiff or swollen joint deformity of the affected joint (e.g., nodules) Physical exam acute gout typically mono-articular login to view 1 more bullet sudden onset of joint login to view 3 more bullets chronic tophaceous gout subcutaneous nodules typically non-tender overlying skin can be taut abnormal color login to view 1 more bullet Studies Labs hyperuricemia (> 6.8 mg/dL) not sufficient for the diagnosis the level may be lower during an attack Synovial fluid analysis joint fluid aspiration and crystal analysis is the gold-standard negatively birefringent needle-shaped crystals under polarized light login to view 1 more bullet Differential Septic arthritis a highly important differential diagnosis to exclude since this changes management distinguishing factors a synovial fluid analysis will demonstrate login to view 3 more bullets Pseudogout distinguishing factors caused by deposition of calcium pyrophosphate crystals crystal analysis will demonstrate weakly positive birefringent rhomboid crystals under polarized light login to view 1 more bullet DIAGNOSIS Making the diagnosis demonstrating monosodium urate crystals in an affected joint via polarizing light microscopy when this is not possible, the diagnosis can be clinically made Treatment Management approach acute attacks can be managed with nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, or colchicine acute gout attacks typically self-resolve in 1-2 weeks; however, treatment will hasten recovery choice of treatment is dependent on certain patient factors (e.g., comorbidities, gout history, attack characteristics, availability, and cost) preventing future attacks are managed by urate-lowering therapy Conservative lifestyle modification indication login to view 1 more bullet examples login to view 3 more bullets Medical medical management of acute attacks NSAIDs login to view 2 more bullets colchicine login to view 2 more bullets corticosteroids login to view 5 more bullets urine alkalization - reduces kidney stones login to view 2 more bullets medical management for preventing a future attack urate-lowering therapy login to view 7 more bullets Prognosis Acute attacks typically self-resolve Patients have an increased risk of recurrence Advanced gout and tophi may result without proper treatment