Gouty Arthritis

1
Gouty Arthritis

• Diagnosis and Treatment

2
Epidemiology

• men women
• mean age of onset 49 60
• incidence (age 32-64) 2.8 1.5
• the lower incidence and later onset of gout in
  women is attributed to more efficient urate
  excretion
• attack before the age of 30 is rare and suggest a
  genetic metabolic disorder

3
Pathophysiology

• Gout is caused by disorders of purine metabolism
  resulting in elevated levels of uric acid
• gt 7 mg/dl in men
• gt 6 mg/dl in women
• prolonged hyperuricemia leads to formation of
  monosodium urate monohydrate crystals

4
Serum Urate Level

• any sudden change in serum urate concentration
  can provoke an acute gouty attack
• sudden increase favors formation of new crystals
• sudden decrease promotes shedding of previously
  formed crystals from the synovial membrane

5
Serum Urate Level

• during a gouty attack, serum urate levels are
  normal in about 20 of cases
• repeat blood tests eventually detect hyperuricemia

6
Manifestations of Hyperuricemia

• subcutaneous tophaceous deposits
• urolithiasis
• nephrolithiasis
• renal diseases involving the tubules,
  interstitium, or glomeruli

7
Treatment

• NSAIDs
• colchcine
• allopurinol
• steroids
• to prevent recurrent attacks, serum urate levels
  should be kept lt 6 mg/dl

8
Differential Diagnosispseudogout

• Goutnegative birefringent needle-shaped
  intraleukocytic crystals
• yellow when parallel
• blue when perpendicular
• Pseudogoutrod- or rhomboid-shaped crystals with
  opposite refractive properties

9
Differential DiagnosisSeptic Arthritis

• Septic and gouty arthritis present with many of
  the same signs and symptoms
• fever and monoarthritis
• Beware both septic and gouty arthritis may
  present in the same joint

10
Differential Diagnosissynovial fluid analysis

• gout septic
• WBC gt 50 k 15 k (5 to 80k)
• PMNs gt 90 70

11
References

• The management of gout.Emerson BT. N Engl J Med
  1996 334445.
• Crystal identification in human synovial fluids
  methods and interpretation.McCarty DJ. Rheum
  Dis Clin North Am 198814253.
• Septic arthritis. In Primer on the Rheumatic
  Diseases 1997 196-200.
• The Inflamed Elbow Afer an Insect Sting.Matfin
  G, Luchsinger A, Martinez J, Adelman H. Hosp
  Practice 1998 33(6)41-44.