[Gout is a crystal-related arthropathy caused by monosodium urate (MSU) deposition. arthropathies, directly related to hyperuricemia due to disorders of purine metabolism and/or decreased uric acid excretion, and belongs to the category of metabolic rheumatic diseases. Gout refers specifically to acute characteristic arthritis and chronic gout stone disease, which can be complicated by renal pathology, with joint destruction and impaired renal function in severe cases, and is also often associated with other components of the metabolic syndrome such as abdominal obesity, hyperlipidemia, hypertension, type 2 diabetes mellitus, and cardiovascular disease. Primary gout is caused by a combination of genetic and environmental factors and has some family susceptibility, but the majority of causes are unknown, except for about 1%, which are caused by congenital defects in purine metabolizing enzymes. Secondary gout occurs in the course of other diseases (such as kidney disease, hematological disease, etc.), or is caused by the use of certain drugs, tumor radiotherapy and other causes. [The prevalence of gout increases with age, but in recent years there is a trend toward younger patients; most female patients appear after menopause. The natural course of gout can be divided into acute attack, intermittent attack, and chronic gouty stone lesion period. Symptoms and signs (1) Acute attack There may be no aura before the attack, and typical attackers are often awakened by joint pain late at night, and the pain increases progressively, reaching a peak in about 12 hours. The affected joints are red, swollen and burning, with tight skin, marked tenderness and limited function. Most of them resolve on their own within a few days or 2 weeks and return to normal. The first attack mostly affects a single joint, with more than 50% occurring in the first metatarsophalangeal joint, and later in the course of the disease, 90% of patients involve this part. The dorsal foot, heel, ankle and knee joints may also be involved. Some patients may have systemic symptoms such as fever, chills, headache, palpitations and nausea, and may be accompanied by elevated white blood cells and increased blood sedimentation. (2) Intermittent attack period Acute arthritis usually has no obvious sequelae after remission, and sometimes there is only skin pigmentation, flaking and itching on the affected area. Most patients relapse within 1-2 years after the initial attack. As the disease progresses, the number of attacks gradually increases, the duration of symptoms lengthens, the asymptomatic interval shortens, and even the symptoms cannot be completely relieved, and the number of affected joints gradually increases, from lower to upper extremities and from distal small to large joints, with involvement of joints such as fingers, wrists, elbows, etc. A few patients may affect the shoulder, hip, sacroiliac, sternoclavicular or spinal joints. Sacroiliac, sternoclavicular or spinal joints may be involved, and the bursa, tendons and tendon sheaths around the joints may be involved, and the symptoms and signs tend to be atypical. (3) Chronic gouty stone lesions Subcutaneous gouty stones and chronic gouty stone arthritis are the result of long-term significant uncontrolled hyperuricemia and significant expansion of the uric acid pool in the body, with large amounts of MSU crystals deposited in the subcutis, synovium, cartilage, bone and soft tissues around the joints. The typical site of occurrence of subcutaneous gout stones is the auricle, but they are also common around recurrent joints, as well as in the hawser, Achilles tendon, and patellar bursa. The appearance is a yellowish-white bulge of varying size under the skin, with a thin skin surface that breaks down and discharges a white powdery or pasty substance that does not heal over time. Subcutaneous gouty stones often coexist with chronic gouty arthritis. Large deposits of gouty stones in the joints can cause joint bone destruction, periarticular tissue fibrosis, and secondary degenerative changes. The clinical manifestations are persistent joint swelling and pain, pressure pain, deformity, and functional impairment. Symptoms are relatively mild in the chronic phase, but there can be acute attacks. (4) Renal lesions ① Chronic urate nephropathy Tiny urate crystals are deposited in the renal interstitium, especially at the papillae of the renal medulla, leading to chronic tubulointerstitial nephritis, causing tubular atrophy and deformation, interstitial fibrosis, and in severe cases, glomerular ischemic sclerosis. The clinical manifestations are decreased urinary concentration function, increased nocturia, low specific gravity urine, small molecule proteinuria, leukocyturia, mild hematuria and tubular pattern. In the late stage, the glomerular filtration function may be decreased and renal insufficiency and hypertension, edema and anemia may occur. The incidence of uric acid urinary tract stones is over 20% in patients with gout and may occur before the onset of gouty arthritis. Smaller stones are excreted in the urine in the form of gravel and can be asymptomatic. Larger stones may block the urinary tract, causing renal colic, hematuria, difficulty in urination, urinary tract infection, dilated renal pelvis, and fluid retention. (3) Acute uric acid nephropathy The level of uric acid in blood and urine rises sharply, and a large number of uric acid crystals are deposited in the renal tubules and collecting ducts, resulting in acute urinary tract obstruction. Clinical manifestations include oliguria, anuria, and acute renal failure; large amounts of uric acid crystals are seen in the urine. This condition is rare in primary gout and is most often caused by secondary causes such as malignancy and its radiotherapy and chemotherapy (i.e. tumor lysis syndrome, tumor lyses syndrome).