I. Stages of gout disease process
(A) Asymptomatic hyperuricemia stage
Blood uric acid concentration increases continuously or fluctuates with age. From the increase of blood uric acid to the appearance of symptoms can last for years to decades, and only when arthritis occurs is it called gout.
Some patients with hyperuricemia do not develop symptoms throughout their lives and are referred to as asymptomatic hyperuricemia.
(B) Acute gouty arthritis (gout attack phase)
Sudden onset of disease at midnight or early morning, with redness, swelling, heat, pain and dysfunction of the affected joints within a few hours. The initial onset is mostly uni-articular, with subsequent involvement of multiple joints. Unilateral bunion and 1st metatarsophalangeal joint are the most common, followed by ankle, knee, wrist, finger and elbow. It may be accompanied by fever, headache, elevated white blood cells and other systemic symptoms.
(C) Intermittent gout attacks
Gout attacks last for a few days to a few weeks and then remit naturally, leaving no sequelae and entering the asymptomatic phase called intermittent phase. If the intermittent period does not lower the blood uric acid concentration to the ideal value (<300μmol/L or <360μmol/L), the gout attacks will become more frequent, last longer and have more severe symptoms as time goes by.
62% of patients relapse within the first year
16% of patients relapsed in 1-2 years
11% of patients have a relapse in 2-5 years
6% of patients relapsed in 5-10 years
5% of patients are seizure-free for 10 years
A minority of patients have only one attack in their lifetime.
(D) Gout stone and chronic gouty arthritis period
1, mostly seen in untreated or poorly treated patients, patients with early prevention of hyperuricemia may not have this phase.
2. Gout stones are sesame-sized to egg-sized yellowish-white gouty nodules formed by uric acid deposits in cartilage, synovium, tendons and soft tissues as a characteristic manifestation. Gout nodules are mostly found in the auricular, metatarsal, interphalangeal, metacarpal, elbow and other joints, and also in the ulnar hawk, talus and Achilles tendon.
3. Excessive formation of gout stones and recurrent inflammation lead to joint stiffness, restricted movement and deformity. The skin on the surface of the gout stone becomes thin, and white powder-like fluid flows from the abrasion, and fistulas may be formed.
4. The lesion has reached a late stage, arthritis attacks are more frequent, the interval is shortened, the pain is increasing, and even the attack cannot be completely relieved afterwards.
(E) Renal lesions
5-12% of patients with hyperuricemia will eventually develop gout, and 1/3 of them may involve the kidneys and develop nephropathy.
1. Uric acid nephropathy
It is caused by the deposition of uric acid in the interstitial tissue of the kidney. In the early stage, it may only show intermittent proteinuria and microscopic hematuria. As the lesion progresses, impaired renal concentration function, chronic renal insufficiency and renal failure (uremia) may occur. Some patients have uric acid nephropathy as the first clinical manifestation.
2. Renal uric acid stones
Renal uric acid stones are present in 20%-25% of patients with primary gout. Small sediment-like stones can be excreted in the urine without symptoms, while larger stones can cause renal colic, hematuria and urinary tract infection. Renal uric acid stones may be the first clinical manifestation in some patients. The incidence of renal uric acid stones is higher in patients with secondary gout who have tumor dissemination or received radiotherapy.
3.Acute renal failure
A large number of uric acid crystals block the urinary tract (renal tubules, renal pelvis or ureter), and the patient suddenly develops oliguria or even anuria, and acute renal failure occurs.
Second, the danger of gout and hyperuricemia
According to the statistics on the causes of death of gout patients in Japan in Asia, uremia is the most common complication due to gout, followed by ischemic heart disease, cerebrovascular disease and malignant tumor. Meanwhile, gout is one of the important risk factors for stroke (stroke), myocardial infarction, and coronary heart disease, and aggravates the poor prognosis of patients.
Common complications (co-morbidities) of gout include obesity (58%); hypertension (58%); hyperlipidemia (45%); diabetes mellitus (20%); gouty nephropathy, kidney stones, renal insufficiency and renal failure (18.6%); ischemic heart disease and atherosclerosis (10%-15%), etc., which are mutually beneficial and promote each other’s deterioration.
1, gouty nephropathy: if gout is not properly treated, long-term persistent hyperuricemia will cause excessive uric acid crystals to precipitate in the kidneys, resulting in gouty nephropathy, which will further develop into uremia.
2, ischemic heart disease: persistent hyperuricemia will cause excessive uric acid crystals to precipitate in the coronary arteries, coupled with hyperagglutination of platelets, both accelerate the progress of atherosclerosis.
3, kidney stones: the more uric acid in the urine, the more acidic the pH, the more likely to occur stones.
4, obesity: obesity will not only make the synthesis of uric acid hyperactive, resulting in hyperuricemia, but also impede the excretion of uric acid, easy to cause gout, combined with hyperlipidemia, diabetes, etc.
5, hyperlipidemia: gout combined with hyperlipidemia a lot, which is very closely related to the occurrence of atherosclerosis.
6, diabetes: oral glucose load test on gout patients, the results found that 30-40% of the combination of mild non-insulin-dependent diabetes. A study of more than 4,000 patients over 10 years found that 25% of diabetes was due to high uric acid.
7. Hypertension: 58% of gout patients are combined with hypertension.
Prognosis of gout disease
1, the prognosis of primary gout without complications and co-morbidities is good.
2, according to statistics, gout patients with nephropathy confirmed by autopsy accounted for 100%.
3.Patients with combined hypertension, coronary artery disease, hyperlipidemia and diabetes depend on the comorbidities and complications.
4.The prognosis of secondary gout depends on the underlying lesion.
5.The mortality rate of hyperuricemia is about 25% when it develops into uremia.
6.About 25% of gout patients die from cardiovascular disease.