Hyperuricemia - Causes, Effects, Diagnosis, and Treatment

What Is Uric Acid?

Uric acid is an acid produced as a result of purine metabolism. Purines are normally present in the body and can be contained in various foodstuffs like peas, beans, beer, and liver. It is a water-insoluble acid. A maximum part of the uric acid is dissolved in the blood, filters in the kidneys, and leaves the body through urine. The normal range of the uric acid in the blood is 3 to 7 mg/dL.

What Is Hyperuricemia?

Elevation in uric acid level to more than 7 mg/dL is called hyperuricemia. The normal pH of uric acid is 7.4. The uric acid circulates in the ionized form of urate. Various conditions can lead to this elevation. The main reason behind elevation may be kidney function impairment. 90% of the excretion of uric acid occurs by the kidneys. Acute or chronic kidney diseases lead to a decrease in the glomerular filtration rate and result in hyperuricemia. 65% of the uric acid produced is excreted by the kidneys. The purine production is accelerated by a purine-rich diet or high cell breakdown. Conditions such as hemolysis and tumor lysis can be a source of purine and increased urate production. The insoluble form of the uric acid is converted into a soluble form by the enzyme uricase.

What Are the Causes of Hyperuricemia?

• Increased Purine Degradation - Purine is a source of uric acid, which, when degraded, releases urate ions.

• High Cell Turnover Rate - Certain conditions like hemolysis lead to severe breakdown of the cells, which in turn produces uric acid.

• Hemolysis - Severe degradation of the red blood cells.

• Rhabdomyolysis - It is a disease in which there is a breakdown of the muscle tissue releasing myoglobin (protein).

• Renal Insufficiency - Impairment of the normal renal function.

• Metabolic Acidosis - Increase in the hydrogen ion concentration in blood is acidosis.

• Diabetes Mellitus - A disease characterized by hyperglycemia (increased level of sugar in the blood).

• Cardiovascular Diseases - Diseases related to the heart.

• Chronic Renal Disease - Long-term untreated kidney disease.

• Metabolic Syndrome - Consists of a group of diseases, including diabetes and high blood pressure.

• Foodstuff That Can Cause Hyperuricemia - Red meat, drinks that has high amount of fructose, bacon, seafoods like mussels, tuna, and green leafy vegetables like asparagus.

What Are the Effects of Hyperuricemia on the Body?

• Uric Acid Stones - Hyperuricemia can cause the formation of the uric acid crystals, which is the largest form of uric acid inside the kidney. Uric acid deposition generally occurs in the acidic environment, which is the distal tubule of the nephron.

• Damage - Permanent damage to the tissues, joints, and bone.

• Gout - It is a disease caused due to the excessive position of uric acid in the synovial fluid of the joints. It is characterized by severe pain and inflammation in the joints, redness, and tenderness.

• Type 2 Diabetes Mellitus - A condition in which the cells in the muscle, fat, and liver become intolerant to insulin. It is the adult-onset of diabetes mellitus which always occurs in middle and late adulthood.

• High Blood Pressure - Elevation in the normal blood pressure.

• Fatty Liver Disease - It is a condition caused by the deposition and storage of extra fat in the liver.

• Pain in Joints - Stiffness and difficulty in movement.

• Swelling - Redness and swelling around the joints can be seen.

• Chronic Gout - The uncontrolled uric acid level can lead to chronic gout.

How to Diagnose Hyperuricemia?

• Blood Tests - This can reveal serum uric acid is more than the normal range, which is more than 6.8 to 7 mg/dL. A complete blood profile like complete blood count (CBC), lipid profile, and calcium and phosphate levels can indicate the presence of any underlying disease leading to the elevation of the uric acid in the body.

• Urine Sample - 24-hour urine uric acid collection of more than 600 mg per day indicates elevated uric acid production.

• Imaging Tests - X-rays can be used to evaluate the presence of swelling in the joints. A renal ultrasound can be referred to patients with uric acid stones.

• Arthrocentesis - It is a test in which a needle is used to aspirate the synovial fluid from the joints to detect the presence of uric acid deposition and diagnose gout.

How to Treat Hyperuricemia?

• Hyperuricemia remains asymptomatic in most patients and does not require medical attention until it develops into gout or nephrolithiasis.

• Drugs that can lower uric acid levels-

  • Xanthine Oxidase Inhibitors - It is used to treat gouty arthritis, nephrolithiasis, and chemo-related hyperuricemia.

  • Rasburicase - Converts the uric acid into allantoin, which is a water-soluble compound and is readily excreted from the kidneys.

  • Probenecid - Inhibits the increased uric acid production.

• The pain and inflammation in gout can be treated by NSAIDs (non-steroidal anti-inflammatory drugs) like Celecoxib, Naproxen, and Ibuprofen can be used.

• Kidney stones of less than 5 mm can be easily excreted by drinking plenty of water every day. Some medications, such as Tamsulosin, can be prescribed by the physician to relax the muscles of the urinary tract. Other techniques such as extracorporeal shockwave lithotripsy can be used for the non-invasive removal of the stone.

Who Is at Risk of Developing Hyperuricemia?

• Medications such as diuretics and immunosuppressants are found to elevate uric acid levels.

• Obesity.

• Advanced age.

• Family history of gout.

• Prolonged condition of dehydration.

• Patients with a history of gout.

• Excessive alcohol consumption.

• Lead exposure.

• Pesticide exposure.

• Kidney disease.

• High blood pressure.

• Hypothyroidism (condition of decreased level of the thyroid hormone).

• Chronic arthritis.

• Extreme physical activity.

• Hyperglycemia (increase in the level of blood sugar).

How to Prevent Hyperuricemia?

• Hyperuricemia can be prevented by thoroughly following the medications prescribed by the physician. Uric acid-lowering medication dissolves the uric acid crystals and helps to lower the overall load.

• Controlling obesity by losing weight and maintaining a normal and healthy lifestyle.

• Avoid eating foodstuffs that can elevate uric acid levels.

• Oatmeal.

• Sweetbreads.

• Yeast supplements.

• Drinking excessive water in case of uric acid nephrolithiasis.

Conclusion:

The treatment of hyperuricemia does not involve a prolonged medical treatment until it develops into gout or nephrolithiasis. Maintaining a constant weight and overcoming obesity can help in the prevention of diseases like gout. Uric acid-lowering medications can alone help in bringing the elevated levels to the normal along with proper diet and exercise. Knowledge about the foodstuff that can elevate uric acid production is necessary. Diagnosis of any underlying disease and treatment of it can help lower the level of uric acid.