A 35-year-old man comes to the office due to recurrent foot pain. In the last 6 months, the patient has had 3 episodes of pain at the base of the left great toe. The pain awakens him from sleep and is associated with redness and swelling but no fever. The first 2 episodes resolved spontaneously, but the current episode has been more severe, and ibuprofen has not provided adequate pain relief. The patient has a history of prediabetes and takes metformin. He works as a butcher and spends much of his time in an air-conditioned room. His diet consists primarily of fried foods and salty, carbohydrate-rich snack foods. He drinks 8-10 cups of coffee and 2 L of diet soft drinks daily and 3 or 4 beers nightly. The patient does not use tobacco or illicit drugs. Temperature is 37.5 C (99.5 F), blood pressure is 142/86 mm Hg, and pulse is 92/min. BMI is 29 kg/m2. Examination shows erythema and tenderness at the left first metatarsophalangeal joint. Aspiration of joint fluid reveals many leukocytes and scattered needle-shaped, negatively birefringent crystals. Which of the following is most likely to have contributed to this patient's condition?
Risk factors for gout | |
Increased uric acid production |
|
Decreased uric acid clearance |
|
Rapid decline in uric acid levels |
|
HGPRT = hypoxanthine-guanine phosphoribosyltransferase. | |
This patient has acute gout, an episodic inflammatory arthritis triggered by deposition of monosodium urate crystals in synovial fluid. Gout usually presents in a single lower extremity joint, most commonly the first metatarsophalangeal joint. The diagnosis is confirmed when joint aspiration reveals an elevated leukocyte count and needle-shaped, negatively birefringent monosodium urate crystals.
Gout arises in the setting of hyperuricemia. Although the underlying cause of hyperuricemia is most commonly unknown (>90% of cases are considered idiopathic), some patients have modifiable risk factors that increase uric acid production (eg, intake of purine-rich foods) or reduce uric acid excretion (eg, diuretic medications). The excessive intake of alcohol is considered one of the most common modifiable risk factors for gout. Alcohol is thought to both reduce urate excretion and increase urate production. In addition, beer is particularly likely to cause gout as it contains high amounts of absorbable purines that are metabolized to uric acid.
(Choice B) Coffee is associated with a lower risk of gout, possibly due to inhibition of xanthine oxidase and reduced breakdown of purines. This effect is also seen with decaffeinated coffee but not with tea.
(Choice C) Heavy consumption of fructose-sweetened soft drinks is associated with an increased risk of gout (due to increased hepatic production of uric acid), but the intake of artificially-sweetened beverages is not.
(Choice D) Patients with diabetes have an increased risk of gout, at least in part due to shared risk factors (eg, obesity). However, metformin use is not associated with an increased risk of gout.
(Choice E) High salt intake may increase the risk of a kidney stone but not gout.
(Choice F) Foods that contain high amounts of trans-fatty acids (eg, commercial baked snack foods, hardened margarines) increase the risk of atherosclerotic heart disease but are not a major risk factor for gout. Gout is provoked by foods rich in purines such as organ meat, red meat, and seafood.
Educational objective:
Moderate to heavy alcohol consumption increases the risk of gout due to increased production and decreased excretion of uric acid. Beer in particular can trigger a gout flare, as many beers contain significant quantities of absorbable purines that lead to increased blood uric acid levels.