Gout is a systemic disease caused by the buildup of uric acid crystals in the joints of the body, causing inflammation, swelling and pain.

You wake up in the middle of the night, and your big toe feels as if it's on fire. It's hot, swollen and so tender that the weight of the blanket on it is nearly intolerable.

If so, you might be experiencing an acute attack of gout - or gouty arthritis - a form of arthritis that's characterized by sudden, severe attacks of pain, redness and tenderness in joints.

When to seek medical advice

If you experience sudden, intense pain in a joint, call your doctor. Gout that goes untreated can lead to worsening pain and joint damage.

Seek medical care immediately if you have a fever and a joint is hot and inflamed, which could be a sign of infection.

Screening and diagnosis

To help diagnose gout, your doctor may withdraw fluid from the affected joint to check for crystals of uric acid in your white blood cells. Other tests may include:

• Urine test. You may have a urine test to measure the amount of uric acid you're excreting.

• Blood test. Your doctor may have you undergo a blood test to measure the uric acid level in your blood.

Complications

Some people with gout develop a chronic form of arthritis, often with discolored deposits under the skin called tophi. A small number of people with gout develop kidney stones.