Elevated Uric Acid: Main Causes

Elevated uric acid on a blood test is not a diagnosis but a signal that purine metabolism has outpaced the body's ability to excrete them. The next question is a single one: where exactly did the imbalance occur — at the input or at the output. We break down the mechanism so that the result stops being a frightening number without context.

What uric acid is and why it is measured

Uric acid is the end product of purine metabolism in humans: it forms when xanthine is oxidized by the enzyme xanthine oxidase. Purines are the building blocks of nucleic acids, and they come from two sources: from the body's own cells, which are constantly being renewed, and from food. Normally the acid dissolves in the blood, is filtered by the kidneys, and is excreted in urine.

A blood test, and less often a 24-hour urine test, is ordered for symptoms of gout, for certain types of anticancer treatment, for kidney stones, and when taking certain medications. Reference values from guidelines: in men — no higher than 420 µmol/L, in women — no higher than 360 µmol/L.

Disordered uric acid metabolism: main mechanisms

Imagine the body as a boiler room that burns purines: fuel comes from food and from renewing cells, and uric acid is the ash. As long as the ash pit works properly, the ash leaves with the urine and no one notices it. A failure can occur on two sides: the furnace burns too much (overproduction) or the removal has broken down (the kidneys excrete less than is formed). The result is the same — hyperuricemia.

Uric acid crystals are poorly soluble in water: when in excess, they form needle-shaped crystals in and around the joints — this is how gout arises. The same process leads to kidney stones and, at extremely high values, to kidney failure. At the same time, hyperuricemia occurs in about a third of the world's population, while joint problems develop far from in everyone.

Why the kidneys do not excrete uric acid

Removal of the ash depends on the kidneys: they filter urates and send them into the urine. Therefore kidney disease and kidney stones are a common cause of uric acid being retained in the blood. The second group is conditions with accelerated formation: massive cell breakdown in leukemia, myeloma, metastatic cancer, and during chemotherapy, and less often inherited enzyme abnormalities such as Lesch–Nyhan syndrome.

Diet, excess weight, and other risk factors

Even with properly functioning kidneys, the ash pit overfills if there is too much fuel. Risk factors are broader than food alone: excess weight, alcohol, menopause, diuretics and certain blood pressure medications, high cholesterol, high blood pressure, kidney disease, osteoarthritis, diabetes, recent surgery or injury.

• Red meat and organ meats — liver, kidneys
• Some seafood: shellfish, anchovies, sardines, trout, tuna
• Alcohol of any type
• High-fructose corn syrup in soda and sweets
• Dehydration, a very large single portion of food, fever, joint injury

Test results are also affected by medications, including aspirin and niacin (vitamin B-3). The doctor knows this, but telling them about everything you take is your part of the work.

Which diseases are associated with high levels

The best-known target of hyperuricemia is gout: sudden severe pain in one joint, most often in the big toe, with swelling and warmth around it; without treatment an attack lasts one to two weeks. The list of associated conditions includes kidney disease and stones, leukemia, myeloma, metastatic cancer, side effects of anticancer treatment, alcohol dependence, and preeclampsia. Long-standing untreated gout leads to joint damage, tophi (firm nodules under the skin on the ears, fingers, elbows), and chronic arthritis.

When an elevated value warrants a doctor visit

A reason to see a doctor is a persistent elevation, especially together with symptoms or with a first attack of joint pain. The doctor may measure uric acid levels, ask about diet and alcohol, refer you to a rheumatologist, take a joint fluid sample with a thin needle, or order a scan. The scope of examination is determined by the doctor.

Elevated uric acid by itself is not a reason to call an ambulance. 103 or 112 — if sudden pain and swelling in a joint are accompanied by a very high fever or a feeling of heat, chills and shivering, nausea or inability to eat, and the pain is increasing: such signs may indicate an infection inside the joint.

Uric acid is one of those values that decide nothing on their own: the number only hints at where to look next. This material is for reference and does not replace a doctor's consultation.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer