Gout

What causes gout

Uric acid is a waste product from breaking down purines, substances found in body cells and many foods. Normally it dissolves in blood and is removed by the kidneys. When levels stay above about 6.8 mg/dL (hyperuricemia), uric acid can crystallize as monosodium urate in joints and soft tissues. The immune system attacks these crystals, causing intense inflammation.

Most people with high uric acid never get gout, but the higher the level, the greater the risk. About 90% of hyperuricemia comes from the kidneys not excreting enough uric acid, rather than the body making too much.

Symptoms

Gout flare

• sudden, severe pain, often starting at night or early morning
• a joint that is red or purple, hot, swollen and extremely tender, so even a bed sheet touching it hurts
• peak within 12 to 24 hours, settling over 1 to 2 weeks
• sometimes low-grade fever

Podagra, gout of the big toe joint, is the classic first attack and happens in about half of people. Other common sites are the midfoot, ankle, knee, wrist, fingers and elbow (olecranon bursa).

Chronic gout

Without treatment, flares can become more frequent and involve more joints. Over years, tophi form: firm, chalky lumps of urate crystals under the skin, on the ears, fingers, toes, elbows and Achilles tendons. Chronic gouty arthritis causes ongoing pain, stiffness and joint damage.

Risk factors

• male sex, and women after menopause
• age over 30 to 40 in men
• obesity and metabolic syndrome
• high blood pressure, diabetes and heart disease
• chronic kidney disease
• diet: red meat, organ meats, shellfish and some fish, sugary drinks and foods high in fructose
• alcohol, especially beer and spirits
• medicines: thiazide and loop diuretics, low-dose aspirin, cyclosporine, tacrolimus
• family history
• dehydration, surgery, illness and fasting, which can trigger flares

Diagnosis

• Joint fluid analysis: removing fluid with a needle and seeing urate crystals under a polarized microscope is the definitive test. It also rules out infection.
• Serum uric acid: helpful, but can be normal during a flare, so it is rechecked 2 to 4 weeks afterward.
• Dual-energy CT or ultrasound: can show urate deposits when fluid cannot be obtained.
• X-rays: normal early, later show characteristic "punched-out" erosions.
• Kidney function, blood sugar and cholesterol checks.

Conditions that look like gout

Treating a gout flare

Start treatment as soon as a flare begins. The earlier, the faster it works.

• NSAIDs such as naproxen or ibuprofen at full anti-inflammatory doses, if safe for your kidneys, stomach and heart. Avoid aspirin, which can worsen gout.
• Colchicine, most effective within the first 12 to 24 hours. Low-dose regimens work as well as high doses with fewer side effects such as diarrhea.
• Corticosteroids, as tablets or a joint injection, for people who cannot take NSAIDs or colchicine.
• Interleukin-1 blockers (anakinra, canakinumab) for difficult cases.
• Self-care: rest and raise the joint, apply ice packs wrapped in a cloth for 20 minutes at a time, and drink plenty of water.

Your doctor can give you a supply of flare medicine to keep at home.

Long-term treatment: lowering uric acid

The American College of Rheumatology recommends uric acid-lowering therapy for people with tophi, joint damage on imaging, or 2 or more flares a year, and it is often considered after a first flare in people with kidney disease, very high uric acid or kidney stones.

• Allopurinol: first choice for most people. It is started at a low dose and increased gradually. People of Southeast Asian (for example Han Chinese, Korean, Thai) or African American descent may be tested for the HLA-B*58:01 gene first, because it raises the risk of a severe allergic rash.
• Febuxostat: an alternative if allopurinol is not tolerated.
• Probenecid: helps the kidneys excrete uric acid, if kidney function is good.
• Pegloticase: an IV infusion for severe, tophaceous gout not controlled by other drugs.

The goal is a uric acid level below 6 mg/dL, or below 5 mg/dL with tophi. This is a "treat to target" approach with regular blood tests. Starting these medicines can briefly trigger flares as crystals dissolve, so low-dose colchicine, an NSAID or prednisone is usually taken for the first 3 to 6 months. Do not stop uric acid-lowering medicine during a flare.

Diet and lifestyle

Diet alone rarely controls gout, but it helps:

• limit: organ meats, red meat, shellfish, anchovies and sardines, beer and spirits, and drinks sweetened with sugar or high-fructose corn syrup
• choose: vegetables (including high-purine vegetables, which do not raise risk), low-fat dairy, whole grains, plant proteins, coffee in moderation
• cherries may reduce flares in some studies
• lose weight gradually if overweight, and avoid crash diets
• drink plenty of water
• ask your doctor about switching from thiazide diuretics to losartan for blood pressure, which lowers uric acid

Complications

• frequent flares and chronic arthritis
• tophi, which can become infected or ulcerate
• joint damage and deformity
• kidney stones made of uric acid
• kidney disease
• gout is linked to higher cardiovascular risk, so heart risk factors should be managed

Outlook

Gout is one of the most treatable forms of arthritis. With consistent uric acid-lowering therapy at target, flares become rare and tophi shrink and can disappear over months to years. Many people stop having attacks entirely.

Frequently asked questions

What triggers a gout attack?

Common triggers include alcohol (especially beer), large meals rich in red meat or seafood, sugary drinks, dehydration, starting or stopping certain medicines such as diuretics, surgery, illness, injury and crash dieting. Anything that suddenly raises or lowers uric acid can trigger a flare.

How long does a gout flare last?

Without treatment, a flare usually peaks within 24 hours and settles over 1 to 2 weeks. Starting anti-inflammatory treatment within the first few hours shortens it considerably, often to a few days.

What is the fastest way to treat a gout flare?

Start a prescribed flare medicine, such as an NSAID, colchicine or a steroid, as soon as symptoms begin. Rest and raise the joint, apply ice wrapped in a cloth, and drink water. Early treatment works much better than waiting.

Do I have to take allopurinol for life?

Usually, yes. Uric acid-lowering medicine works only while you take it, and stopping often leads to flares returning. Some people with major weight loss or lifestyle change may be able to reduce the dose with their doctor's guidance.

What foods should I avoid with gout?

Limit organ meats, red meat, shellfish, anchovies and sardines, beer and spirits, and sugar-sweetened drinks. You do not need to avoid high-purine vegetables like spinach or mushrooms. Low-fat dairy, vegetables and water are helpful choices.