What are the symptoms of gout?

Gout is a type of crystalline arthritis caused by hyperuricemia, primarily characterized by abnormally elevated levels of uric acid in the body. This leads to deposition of urate crystals in joints, soft tissues, and the kidneys, resulting in acute inflammatory reactions. The symptoms of gout mainly include the following aspects:

1. Asymptomatic phase: Also known as the hyperuricemia phase, during this stage the patient's serum uric acid concentration is elevated, but no clinical symptoms of gout are present. This phase can last for several years or even decades.

2. Acute arthritis: Commonly affects the joints of the lower limbs, especially the first metatarsophalangeal joint. It often suddenly develops at night, presenting as redness, swelling, heat, pain, and functional impairment in the affected joint. The pain is severe, sharp, and unbearable, similar to a cutting sensation.

3. Tophi: Long-standing hyperuricemia can lead to deposition of urate crystals in subcutaneous tissues, forming tophi. These tophi commonly appear on the earlobes, elbows, knees, and toes. They present as white or yellow nodules under the skin and may sometimes rupture, discharging a white substance.

4. Kidney involvement: Long-term hyperuricemia can also lead to kidney damage, such as uric acid kidney stones and gouty nephropathy, presenting with symptoms including hematuria, proteinuria, and oliguria.