What causes gout?

What causes gout?

What causes gout?

Urate crystals (which form due to an accumulation of uric acid) in the joint cause symptoms of gout. The body naturally produces uric acid from the food we eat as it breaks down purines (often found in red meat, organ meat and seafood, as well as alcoholic and fructose / sweetened beverages). High sodium (salt) content can also lead to high uric acid build-up.

Uric acid is produced by purines in the liver, it then dissolves in the bloodstream and passes through the kidneys, which then filter out toxins and produce urine for excretion (via the urinary tract – ureters, bladder and urethra). Any uric acid that remains is moved through the intestines and broken down by naturally occurring bacteria.

If there is too much uric acid in the system (hyperuricemia) or the kidneys fail to excrete enough of the substance, a build-up can occur. Sharp, needle-like crystals then develop from the build-up, and white blood cells mistake these urate crystals for a ‘foreign object’ that is invading the body and causing distress to the natural flow and function of the affected joint. These cells then surround the crystals in attempt to neutralise them. Inflammation, pain, heat and swelling soon follow.

Dehydration and undernourishment can make it difficult for the body to be able to eliminate or expel uric acid. A build-up of urate crystal deposits in the joints then occurs. Kidney disorders and abnormal thyroid function, as well as certain medications, like immunosuppressive fungal drugs or diuretics may also make it difficult for the body to expel uric acid.

Excess uric acid does not always result in the formation of crystal deposits in the body, in fact fewer than 20% of hyperuricemia cases lead to arthritic gout disease. (1)

 Uric acid crystal needles in synovial, seen under a microscope.

Factors which contribute to increasing the risk of gout:

  • Diet (consuming a high purine diet rich in red meat and shellfish, beverages which have been sweetened with fruit sugar / fructose, and excessive alcohol consumption, especially beer)
  • Medical conditions (high blood pressure / hypertension, diabetes and insulin resistance, degenerative arthritis, thyroid abnormalities, conditions affecting the heart or kidneys, pneumonia and metabolic syndrome)
  • Medications and medical treatments (thiazide diuretics / water-based medications, low-dose aspirin, beta-blockers, anti-rejection drugs taken following an organ transplant, as well as cancer treatments which lead to the secretion of uric acid when malignant cells are destroyed).
  • Obesity (excess weight can lead to the overproduction of uric acid and difficulties with the kidneys being able to process and expel uric acid from the body)
  • Heredity (a family history of gout can make a person more susceptible to the inflammatory condition)
  • Age and sex (Women tend to experience higher levels of uric acid after menopause and may become more susceptible to gout around this time in life. Men typically have higher uric acid levels post puberty and commonly experience gout attacks between the ages of 30 and 50 years of age)

Gout triggers

Anything that effectively alters the amounts of uric acid on either side of normal (causing too little or too much) can trigger a gout attack or flare (caused by urate crystal deposits in the joints). A change can lead to sudden symptoms. Triggers relate to the most prominent risk factors and include:

  • Dietary overindulgence (excessive alcohol consumption, high intakes of red meat, organ meat, sardines, anchovies, mussels, salmon and vegetables such as spinach etc.)
  • Malnutrition and dehydration (causes a lack of water in the body, thus disabling normal amounts of uric acid excretion)
  • Taking of certain medications known to cause changes in uric acid, including treatments for cancer (chemotherapy)
  • Intravenously administered (IV) contrast dyes used for screening / diagnostic purposes
  • Stress, medical trauma or injury (hospital visits due to illness or injury and surgical procedures)

Not every risk factor associated with gout will trigger an attack or flare. Triggers vary from person to person. For some certain foods will most often trigger an attack. For others, it may be a lack of hydration or even going through a stressful time in their lives. Normally it is reasonably simple to connect the dots between a potential trigger and the resulting symptoms. For instance, overindulging in beers one afternoon may likely result in a triggered attack by the early hours of the next morning.

Reference

1. University of Maryland Medical Center. May 2013. Gout: https://nei.nih.gov/health/cataract/cataract_facts [Accessed 15.10.2017]

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