Chronic gout is a recurrent form of arthritis that is caused by a buildup of uric acid crystals in the fluid around the joints. These crystals can irritate the cartilage and cause inflammation in the joint. Patients suffering from chronic gout may first experience acute attacks of pain, swelling, and restricted movement. After several untreated acute episodes of gout, the condition can become chronic.
Uric acid is a metabolic breakdown product of purines, the nitrogen-containing bases that are found the nucleic acids DNA and RNA. At the time of cell death, purines are released from cell nuclei and uric acid is formed. Excess purine may be present after DNA or RNA synthesis and this purine is also broken down into uric acid. Molecules such as adenosine-5’-triphosphate (ATP) and guanosine-5’-triphosphate (GTP) that transport energy to cells contain purine as well.
Purines are also ingested as part of the diet. They are found in high concentrations in animal-based foods such as liver, brains, herring, and sardines. Some plant-based foods, such as oatmeal and mushrooms, also contain purines.
Patients suffering from chronic gout usually have several outbreaks of acute gout with each outbreak followed by a period of remission. As this condition progresses, the periods between episodes get shorter and shorter. Chronic gout can either develop because the patient produces too much uric acid or because the patient is unable to excrete enough uric acid from the body.
Symptoms of chronic gout can appear in any joint but most commonly occur in the first joint of the big toe. Diagnosis is made by taking a patient history of symptoms and outbreaks. A blood test may be done that can measure uric acid levels. To confirm the diagnosis, fluid can also be extracted from the joint and examined for crystals under a microscope.
During a gout attack, the patient should rest the joint, drink fluids, and eat a diet high in fruits and vegetables. Anti-inflammatory medications may relieve pain during the outbreak. A medication called colchicine may help reduce inflammation by interfering with the ability of immune cells to ingest the uric acid crystals.
Long-term treatment should focus on reducing uric acid levels in the blood and preventing any future attacks of gout. The medication allopurinol may be prescribed because it inhibits the enzyme that converts purine to uric acid. Following a diet high in fruits and vegetables and low in purines may help relieve symptoms of chronic gout.