Hyperuricaemia

What Is Uric Acid?

Uric acid is a metabolic waste that is found in the blood. It is formed as a result of purine breakdown. (Purines are substances that occur naturally in the body and are also present in some foods.)

What Is Hyperuricaemia?

When uric acid levels are high, the condition is called hyperuricaemia.

Why Is Uric Acid Checked?

Gout Diagnosis: Elevated uric acid levels can lead to gout, a form of arthritis.

Kidney Disease: High uric acid levels may indicate kidney problems or disease.

Kidney Stones: Uric acid can contribute to the formation of kidney stones.

Monitoring Medication Side-Effects: Certain medications can increase uric acid levels.

What Are the Symptoms of High Uric Acid?

Joint Pain: Often associated with gout.

Kidney Stones: Severe pain in the side or back.

Kidney Disease: Fatigue, or changes in urination.

What Are the Causes of High Uric Acid?

Diet: Consuming purine-rich foods.

Kidney Conditions: Certain kidney problems reduce the ability to filter uric acid.

Medications: Certain diuretics or chemotherapy drugs increase uric acid levels as their drug effect.

Genetics: Family history of gout or hyperuricaemia.

Management of Hyperuricaemia

1. Dietary Changes: Limit purine-rich foods and alcohol.
2. Hydration: Drink plenty of water.
3. Medications: Urate-lowering therapy may be prescribed.

Can Chronic High Levels of Uric Acid Cause Cardiovascular Problems?

Uric Acid and Endothelial Damage

Yes, elevated uric acid levels (hyperuricaemia) have been associated with endothelial dysfunction, which can lead to various cardiovascular and renal issues.

Mechanisms of Endothelial Damage

1. Oxidative Stress: Uric acid can increase oxidative stress, damaging endothelial cells.
2. Inflammation: Hyperuricaemia promotes inflammation, further impairing endothelial function.
3. Nitric Oxide Reduction: Uric acid may reduce nitric oxide availability, crucial for vascular relaxation.
4. Endothelial Dysfunction: Impaired vasodilation and increased vascular tone.

Clinical Implications

– Cardiovascular Disease: Associated with hypertension, atherosclerosis.
– Kidney Disease: Hyperuricaemia linked to CKD progression.
– Gout: Acute inflammatory arthritis.

Management

– Lifestyle Changes: Diet, hydration, weight management.
– Medications: Urate-lowering therapy (e.g., allopurinol).
– Monitoring: Regular check-ups for kidney function, cardiovascular risk.

Research Directions

– Causal Role: Debate on whether uric acid is causal or marker.
– Therapeutic Targets: Exploring uric acid-lowering therapy.

Factors Contributing to Increased Uric Acid Levels

Uric acid levels can rise due to various factors, including:

Dietary Factors

1. Purine-Rich Foods: Consuming foods with high purine content, such as:
   – Organ meats (liver, kidney, etc.)
   – Red meat
   – Seafood (anchovies, sardines, etc.)
2. Sugary Drinks: High-fructose corn syrup can increase uric acid production.
3. Alcohol: Especially beer and spirits, which can impair uric acid excretion.

Medical Conditions

1. Kidney Disease: Impaired kidney function reduces uric acid excretion.
2. Obesity: Excess body weight can increase uric acid production.
3. Metabolic Syndrome: Associated with insulin resistance and obesity.
4. Gout: A form of arthritis caused by uric acid crystal deposition.

Medications

1. Diuretics: Certain diuretics can reduce uric acid excretion.
2. Chemotherapy: Some treatments can increase uric acid levels.
3. Immunosuppressants: Certain drugs may affect kidney function.

Genetic Factors

1. Family History: Genetic predisposition to hyperuricaemia or gout.

Other Factors

1. Dehydration: Inadequate fluid intake can concentrate uric acid in the blood.
2. Stress: Chronic stress may contribute to elevated uric acid levels.

Prevention and Management

1. Hydration: Consume a lot of water to flush out uric acid.
2. Dietary Changes: Minimize intake of foods rich in purine, and sugary drinks.
3. Weight Management: Maintain a healthy weight.
4. Regular Monitoring: Especially if you have a family history.
5. Diuretics in Heart Failure and Uric Acid: Yes, diuretics are commonly used in heart failure to reduce fluid overload, but they can increase uric acid levels (hyperuricaemia) as a side-effect. This raises a question: Could hyperuricaemia indirectly worsen heart problems?

How Diuretics Contribute to Hyperuricaemia

1. Reduced Renal Blood Flow: Diuretics can decrease blood flow to the kidneys, impairing uric acid excretion.
2. Volume Depletion: Excessive diuresis can lead to dehydration, concentrating uric acid in the blood.
3. Increased Uric Acid Reabsorption: Some diuretics (e.g., loop and thiazide diuretics) can enhance uric acid reabsorption in the kidneys.

Hyperuricaemia and Heart Health

1. Vascular Dysfunction: Elevated uric acid can impair endothelial function, contributing to hypertension and atherosclerosis.
2. Inflammation: Hyperuricaemia promotes inflammation, exacerbating cardiovascular disease.
3. Kidney Damage: Chronic hyperuricaemia can worsen kidney function, further complicating heart failure management.

Clinical Considerations

1. Monitoring: Regularly check uric acid levels in patients on diuretics.
2. Dose Adjustment: Consider adjusting diuretic doses or switching to alternatives.
3. Urate-Lowering Therapy: May be necessary in some cases.

Management Strategies

1. Lifestyle Changes: Encourage hydration, weight management, and a balanced diet.
2. Medication Review: Consider alternatives to diuretics or adding uric acid-lowering therapy.
3. Close Monitoring: Regularly assess kidney function and cardiovascular status.

Purine Content in Food

Purines are naturally occurring substances found in many foods. While some purine intake is normal, excessive consumption can increase uric acid levels.

High-Purine Foods

1. Organ Meats
   – Liver
   – Kidney
   – Sweetbreads
2. Seafood
   – Anchovies
   – Sardines
   – Mackerel
   – Herring
   – Trout
   – Tuna
   – Scallops
3. Red Meat
   – Beef
   – Pork
   – Lamb
4. Game Meats
   – Venison
   – Wild game birds

Moderate-Purine Foods

1. Poultry
   – Chicken
   – Turkey
   – Duck
2. Fish (Not Listed as High-Purine)
   – Cod
   – Haddock
   – Snapper
3. Legumes
   – Beans (e.g., kidney beans, black beans, etc.)
   – Peas
   – Lentils

Low-Purine Foods

1. Dairy
   – Milk
   – Yogurt
   – Cheese
2. Vegetables
   – Most are low in purines (e.g., lettuce, tomatoes, cucumbers, etc.)
3. Fruits
   – Most fruits are low in purines
4. Grains
   – Bread
   – Pasta
   – Rice

Beverages

– Alcohol: Beer and spirits can increase uric acid levels.
– Sugary Drinks: High-fructose corn syrup can raise uric acid.

Tips for Managing Purine Intake

1. Balanced Diet: Enjoy purine-rich foods in moderation.
2. Stay Hydrated: Drink plenty of water.
3. Consult a Professional: For personalised dietary advice.