Hyperuricemia and Its Causes

Hyperuricemia occurs when the blood contains too much uric acid. This excess can lead to gout, kidney issues, cardiovascular problems, and more. Uric acid is the product of the metabolic breakdown of purines and is a standard element of urine. The many causes of hyperuricemia mean symptoms may be different from person to person, causing either increased or decreased production of uric acid, or a combination of the two.

Purine-Rich Diet

One of the simplest causes of hyperuricemia is eating and drinking too many high-purine foods and beverages. These include

• All types of alcoholic beverages
• Fish and shellfish such as mussels, scallops, haddock, trout, sardines, herring, anchovies, and herring
• Game meats such as venison and turkey
• Organ meats like liver
• Bacon

Some foods have moderate purine levels but can still contribute to hyperuricemia. These include

• Common meats like beef, chicken, duck, pork, and ham
• Shellfish, including oysters, lobsters, crab, and shrimp

Kidney Disease

Hyperuricemia has an interesting relationship with the kidneys. Kidney issues can lead to hyperuricemia, and hyperuricemia can cause kidney issues. As the kidneys filter blood, they also filter uric acid. Over time, uric acid can accumulate and form large urate crystals, a combination of urate and calcium. When these move through the kidneys, their size and shape damage the passageways, even leaving scars in some cases. With enough damage and scarring, the crystals can cause kidney disease and failure.

Visceral Fat

Some medical experts list obesity as a cause of hyperuricemia, but this is not entirely accurate. A 2015 study found that people who were not obese but had high visceral fat levels were more likely to have gout than other individuals. Bodies with high fat levels produce more insulin. An excess of insulin traveling through the body can inhibit the kidneys’ ability to eliminate uric acid. Additionally, people with high levels of visceral fat tend to have diets that include more purine-rich foods. This leads to a natural accumulation of uric acid.

Psoriasis

Doctors frequently find that patients with psoriasis have high levels of serum uric acid. Psoriasis is a condition that causes skin cells to rapidly build up on the skin’s surface, leading to itchy and often painful scales and red patches. The exact relationship between uric acid and psoriasis remains unknown, but some physicians believe they influence each other. Researchers have not yet found a causal relationship between the two, but it is possible that understanding this connection will lead to better psoriasis treatments in the future.

Paget’s Disease

Normally, new bone tissue slowly replaces old bone tissue as part of the body’s recycling process. Paget’s disease interferes with this process and can cause bones to become fragile or misshapen. Though researchers do not yet understand the relationship, people with active Paget’s disease tend to have higher uric acid levels. Some studies suggest that Paget’s disease may be causing metabolic issues that then lead to excess purine breakdown.

Medications and Vitamins

Several medications and vitamins tend to cause hyperuricemia. Diuretics prompt the kidneys to release more sodium into the urine. This draws excess water from the blood, leading to lower blood pressure and an increase in urination. However, because the body is losing fluid, the concentration of the remaining fluid increases. As a result, uric acid levels that were once healthy become dangerously high. Certain vitamins, such as B3, can also lead to high uric acid levels.

Purine Metabolism Issues

Complex purine metabolism failures can also cause hyperuricemia. Certain enzymes play central roles in the metabolism and breakdown of purines. If there is a deficiency of one of these enzymes, such as hypoxanthine-guanine phosphoribosyltransferase (HGPRT), then the body will overproduce uric acid. Overactivity of phosphoribosyl pyrophosphate (PRPP) can cause similar issues. Both of these problems are symptoms of Lesch-Nyhan Syndrome.

Down Syndrome

Many studies show that people with Down syndrome tend to have hyperuricemia. This excessive increase of uric acid appears to begin in early childhood. As the child ages, uric acid levels continue to increase, leading to hyperuricemia. Research reveals the excess uric acid is the result of an overproduction of urate. A 1979 study in the Journal of Rheumatology found that this may be due to glomerular dysfunction. Glomerular refers to the glomerulus, a small ball that helps make up the functional unit of the kidney.

Thyroid Issues

Research shows that both hypothyroidism and hyperthyroidism can lead to hyperuricemia. The thyroid is a small gland that produces hormones that control many of the body’s metabolic activities. Hyperthyroidism means the body is creating too many of these hormones, while hypothyroidism means it is not creating enough. In hyperthyroidism, hyperuricemia is the result of an increase in urate production. Hypothyroidism causes excess uric acid due to poor blood flow through the kidneys and glomerular dysfunction.

Tumor Lysis Syndrome

When cancer cells break down, they release various substances into the blood. Occasionally, this break down occurs so rapidly that the kidneys cannot filter all of the new substances, and the individual develops tumor lysis syndrome (TLS). Large-scale cell breakdown and death leads to high levels of various nucleic acids. Among them, purines become uric acid through the normal process. However, because the concentration is so much higher, the body cannot excrete uric acid in the urine. This results in a dramatic increase of urate crystals in the blood, kidneys, and joints.