Causes and risk factors of gout
Gout results from increased uric acid in the blood, which leads to the deposition of monosodium urate crystals in the joint or any other tissue. Uric acid is the product of the metabolism of purine proteins (nucleoproteins that contribute to DNA synthesis). Kidneys get rid of the uric acid in the urine and prevent its deposition in the body tissues. But in certain conditions, hyperuricemia may occur due to increased production or decreased excretion of the uric acid.
1) Increased uric acid production may be:
- Primary: It results from a defect in the HGPRT(Hypoxanthine-Guanine-Phosphoribosyl-Transferase) enzyme, which contributes to purine metabolism. This enzyme reduces uric acid production. It converts the hypoxanthine into Inosine monophosphate, which reverses the direction of purine metabolism.
- Secondary: Some medical conditions may increase the purine metabolism and uric acid production, such as leukemia, lymphoma, sarcoidosis, and psoriasis. Also, chemotherapy of leukemia and lymphoma increases the release of uric acid into the blood due to increased purine turnover.
2) Reduced uric acid excretion may be:
- Primary: Idiopathic isolated tubular deficiency
- Secondary:
- Renal failure
- Dehydration -due to decreased renal blood flow-
- Hypothyroidism and hyperparathyroidism
- Acidosis: such as ketoacidosis in diabetes mellitus, lactic acidosis as in alcohol, and starvation
♦ Besides the causes, some risk factors increase the risk of gout, such as:
- Age and gender: Gout is more common in males who are 40 or 50 years old. Before menopause, the risk of gout is low in females, but it increases postmenopausal.
- Positive family history of gout.
- Diet: Purine-rich foods increase the gout risk, such as red meat, organ meat, shrimp, dried mushrooms, dried anchovies, and other seafood like scallops, tuna, and sardines. Also, fructose-rich foods and drinks increase the risk of gout.
- Alcohol: It is one of the most potent risk factors of gout; more alcohol consumption means a higher risk of gout.
- Health problems, such as hypertension, diabetes mellitus, obesity, dyslipidemia, lead poisoning, and heart failure, may increase the risk of getting gout.
- Surgery and trauma
- Infection
- Dehydration and starvation
- Medications: such as diuretics, pyrazinamide, the low dose of aspirin, the high dose of niacin (vitamin B3), angiotensin-converting enzyme inhibitors (ACEIs), beta-blockers, and immunosuppressive drugs like cyclosporine
⇒ Now, we will discuss the clinical presentation of gout.
