​Five major hazards of hyperuricemia

*It is only for medical professionals to read for reference.
The hazards of hyperuricemia are potential and continuous, and the long-term hazards are even greater, and sufficient clinical attention must be drawn! Uric acid is a catabolism product of purine nucleotides in the human body.
80% of purine nucleotides are produced by the metabolism of human cells, and 20% are obtained from food.

Purine is oxidized and metabolized by the liver into uric acid, which is excreted by the kidneys and intestines.

Under normal circumstances, the human kidneys can excrete uric acid to maintain the normal concentration of uric acid in the blood.
Hyperuricemia is often caused by purine metabolism disorders and/or reduced uric acid excretion.

In January 2020, the Endocrinology Branch of the Chinese Medical Association officially released the "Guidelines for the Diagnosis and Treatment of Hyperuricemia and Gout in China (2019)".
The diagnostic criteria for hyperuricemia are defined as: regardless of men and women, the fasting serum uric acid level is measured twice on different days.
, When the serum uric acid level>420μmol/L (about 7mg/dl), it is hyperuricemia (HUA).

In order to popularize the knowledge of HUA prevention and treatment and make the public pay attention to the hazards of HUA, remember the diagnostic threshold of "420".
As early as 2017, gout expert Professor Zou Hejian proposed to set April 20 (420) as "420" every year.
All the people pay attention to gout day.
"
Elevated uric acid may "damage" the whole body.
Gout, diabetes, kidney damage, and cardiovascular and cerebrovascular diseases are all related to high blood uric acid levels.

When 420 is about to come, the author refers to the literature and talks about the harm that HUA may bring.

 We all know that HUA is the culprit of gout.
In fact, HUA not only harms joints.
When blood uric acid exceeds saturation, urate crystals will be precipitated and deposited in various parts of the body, such as joints, blood vessel walls, and soft tissues; long-term high uric acid The state may also bring adverse effects on the circulatory system, endocrine and metabolic system, urinary system and many other aspects.

  Hazard 1: Damage to joints and skin connective tissue, causing gout.
HUA is the culprit of gout.
The prevalence of gout increases with the increase of blood uric acid level.
Gout includes gouty arthritis and tophi.

Studies have reported that when serum uric acid is <360μmol/L, 360~479μmol/L and >480μmol/L, the prevalence of gout is 1.
3%, 3.
2% and 17.
6%, respectively.

A study followed up for 2 to 10 years showed that when blood uric acid was greater than 360 μmol/L, 87.
5% of patients had knee joint fluid urate crystals, while when blood uric acid was ≤360 μmol/L, only 43.
8% of patients had crystals.
.

 1.
Acute gouty arthritis Acute gouty arthritis usually occurs in a single joint of the lower limbs, with a typical onset of rapid onset, and the symptoms develop to a peak within a few hours.
The joints and surrounding soft tissues show obvious redness, swelling, heat, pain, and severe pain.
.

When large joints are affected, there may be joint exudation, and may be accompanied by systemic symptoms such as headache, fever, and increased white blood cell count.

More than half of the patients first started at the first metatarsophalangeal joint of the foot, and this joint was involved in about 90% of the patients throughout the course of the disease.
Other metatarsophalangeal, ankle, knee, finger, wrist, and elbow joints are also common sites, while the shoulder, Joints such as the hip and spine are rarely affected.

Local joint injuries (such as trauma), tight shoes, excessive walking, surgery, full meals, drinking, dehydration, fatigue, cold, moisture, and infection may all be predisposing factors.

The natural course of the disease is usually less than 2 weeks, and the symptoms can be relieved within a few hours if the treatment is timely.

 2.
Because patients with chronic gouty arthritis and tophis have not persisted in controlling HUA for a long time, more joints are involved, gout attacks become frequent, and they gradually progress to chronic, bilaterally involved, polyarthritis, and eventually joint deformities.
Gout nodules or tophi are formed near joints, tendons, tendon sheaths, and skin connective tissue (such as the auricle).

 Harm 2: Injury blood vessels and promote arteriosclerosis.
It is an independent risk factor for hypertension and cardiovascular and cerebrovascular diseases.
1.
Atherosclerosis: Soluble uric acid can directly damage vascular endothelial cells.
The higher the concentration of uric acid, the greater the impact on the endothelium.

In HUA patients, urate crystals can be precipitated and deposited on the blood vessel wall, and damage the vascular endothelium by inducing an inflammatory response.

In addition, HUA will also interact with hypertension, hyperlipidemia, hyperglycemia, etc.
, and jointly promote the formation of atherosclerosis.

Studies have found that uric acid-lowering treatment can delay the process of atherosclerosis.

 2.
HUA is an independent risk factor for hypertension: Studies have shown that for every 60 μmol/L increase in blood uric acid level, the relative risk of hypertension increases by 13%.

Hypertension and high uric acid are closely related to atherosclerosis.

3.
HUA is a risk factor for heart failure, which is closely related to its occurrence, development and prognosis: the prevalence of HUA in patients with heart failure is as high as 55%-60%.
The higher the patient's blood uric acid level, the more serious the heart failure; Studies have confirmed that for patients who have been diagnosed with coronary heart disease, the death rate of people with blood uric acid higher than 450 μmol/L is 5 times that of people with blood uric acid lower than 300 μmol/L.

4.
HUA is an independent risk factor for stroke: HUA promotes the occurrence of ischemic stroke and increases the risk of stroke.

In addition, the long-term follow-up of non-stroke patients found that the blood uric acid level can be used as an indicator for the prognosis of patients with acute ischemic stroke.
Especially in female patients, the increase in blood uric acid level may be the result of asymptomatic cerebral infarction and expected stroke.
Important serological indicators, through long-term management of HUA, can effectively reduce blood uric acid levels, reduce the occurrence of ischemic stroke and poor prognosis, which may have more important significance for preventing stroke in female HUA patients.

 Hazard 3: Injury to the kidneys, leading to gouty nephropathy, kidney stones, etc.
1.
Gouty nephropathy: Long-term HUA patients may have kidney damage, including chronic urate nephropathy, kidney stones, etc.

Among them, chronic urate nephropathy is also called gouty nephropathy, which can be manifested as decreased urine concentration (such as increased nocturia, low specific gravity urine, small molecule proteinuria) or decreased glomerular filtration rate, because gout patients are often accompanied by Hypertension, arteriosclerosis, kidney stones, urinary tract infections, etc.
, so gouty nephropathy may be the result of a combination of factors.

2.
Kidney stones: urate deposits in the kidneys can form kidney stones.
The main components of the stones are uric acid stones and calcium oxalate stones.
The increase in acid urine and uric acid concentration and the supersaturation are the two main factors for the formation of uric acid stones.
In addition, obesity , Metabolic syndrome, chronic diarrhea, and diabetes are also risk factors for the formation of uric acid stones.
Some HUA patients have symptoms of kidney stones even earlier than the onset of arthritis, and patients often have acute attacks of low back pain or hematuria.

3.
Renal failure: A large number of uric acid crystals widely block the lumen of the renal tubules or cause urinary tract obstruction, which may lead to acute uric acid nephropathy, chronic uric acid nephropathy, and renal failure.

Chronic obstruction can cause hydronephrosis and substantial renal atrophy.
If not diagnosed and treated in time, it can eventually develop into end-stage renal disease.

Studies have shown that for every 60 μmol/L increase in blood uric acid, the risk of chronic kidney disease (CKD) increases by 70%, and the risk of worsening renal function increases by 14%.

The prevalence of CKD in patients with normal blood uric acid level is about 11%, and HUA combined with CKD is as high as 32.
7%.

Hazard 4: Disorderly metabolism, aggravating or causing diabetes, obesity and hyperlipidemia 1.
HUA is an independent risk factor for type 2 diabetes: as the level of uric acid increases, the risk of diabetes is higher.
Studies have shown that the level of blood uric acid is higher.
An increase of 60μmol/L increases the risk of new-onset diabetes by 17%, and the risk of diabetes in HUA patients is 95% higher than that of patients with normal blood uric acid.

2.
Exacerbated obesity and hyperlipidemia: The proportion of HUA population with hyperlipidemia and obesity is as high as 68% and 71% in women and men, respectively; obese people have increased blood uric acid levels, which are manifested by different types of obesity Different morbidities; many patients have effectively controlled their weight after effective uric acid-lowering treatment.

Similarly, lipid-lowering therapy can also assist in uric acid-lowering therapy.

Hazard 5: Damage to the hair, leading to increased male hair loss, androgenic alopecia (AGA) is a common type of male hair loss.
The prevalence rate of AGA in men in my country is about 19.
9%-21.
3%.
Over time, until only a small amount of hair remains on the sides and back of the head.

AGA can occur in men between the ages of 20 and 30, and its severity increases with age.
AGA often leads to an increase in the psychological pressure of the patient and a decrease in the quality of life.

Researchers in my country have evaluated the relationship between HUA and AGA.

The results of the study showed that overall, the uric acid level of AGA patients was significantly higher than that of the control group (P<0.
001), and men with AGA had a higher risk of developing HUA.

It shows that there is a significant correlation between Chinese male HUA and AGA, especially in patients with early-onset AGA (<30 years old).

  Concluding remarks The hazards of HUA are potential and continuous.
The long-term hazards are greater, and sufficient clinical attention must be drawn.
Therefore, facing the "fourth highest" of human health, our clinical specialists should be vigilant, early detection and early intervention.

Nevertheless, uric acid is not useless in the human body.
Studies have shown that a high-purine diet can delay the progression of patients with mild cognitive impairment to Alzheimer's disease.

Elevated blood uric acid levels can help reduce the occurrence of Alzheimer's disease and protect the cognitive impairment of patients with Alzheimer's disease.

Low blood uric acid levels increase the risk of cognitive decline in patients with mild cognitive impairment.

In addition, the increase of blood uric acid level also helps to reduce the incidence of Parkinson's disease and delay its progression.

Male patients with high blood uric acid levels or gout have a relatively low risk of Parkinson's disease, while female patients have no significant correlation.

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