What is Gout ?

Gout (High Uric Acid/hyperuricemia) (also known as podagra when it involves the big toe) is a form of arthritis, but there's a lot more to it. Gout is a painful form of arthritis that is caused by high uric acid levels in your blood. So, we know that it's a medical condition usually characterized by recurrent attacks of acute inflammatory arthritis—a red, tender, hot, swollen joint. The metatarsal-phalangeal joint at the base of the big toe is the most commonly affected (approximately 50% of cases). However, it may also present as tophi, kidney stones, or urate nephropathy. It is caused by elevated levels of uric acid in the blood. The uric acid crystallizes, and the crystals deposit in joints, tendons, and surrounding tissues. Clinical diagnosis is confirmed by seeing the characteristic crystals in joint fluid. Treatment with nonsteroidal anti-inflammatory drugs (NSAIDs), steroids, or colchicine improves symptoms. Once the acute attack subsides, levels of uric acid are usually lowered via lifestyle changes, and in those with frequent attacks, allopurinol or probenecid provide long-term prevention. Gout has increased in frequency in recent decades, affecting about 1–2% of the Western population at some point in their lives. The increase is believed due to increasing risk factors in the population, such as metabolic syndrome, longer life expectancy and changes in diet. Gout was historically known as "the disease of kings" or "rich man's disease".

Pathophysiology Gout is a disorder of purine metabolism, and occurs when its final metabolite, uric acid, crystallizes in the form of monosodium urate, precipitating in joints, on tendons, and in the surrounding tissues. These crystals then trigger a local immune-mediated inflammatory reaction, with one of the key proteins in the inflammatory cascade being interleukin 1β. An evolutionary loss of uricase, which breaks down uric acid, in humans and higher primates has made this condition common.

The triggers for precipitation of uric acid are not well understood. While it may crystallize at normal levels, it is more likely to do so as levels increase. Other factors believed important in triggering an acute episode of arthritis include cool temperatures, rapid changes in uric acid levels, acidosis, articular hydration, and extracellular matrix proteins, such as proteoglycans, collagens, and chondroitin sulfate. The increased precipitation at low temperatures partly explains why the joints in the feet are most commonly affected. Rapid changes in uric acid may occur due to a number of factors, including trauma, surgery, chemotherapy, diuretics, and stopping or starting allopurinol. Calcium channel blockers and losartan are associated with a lower risk of gout as compared to other medications for hypertension.