What is gout?
- Gout is a very common form of inflammatory arthritis that affects 4.5 per cent of Australians.
- Gout specifically refers to arthritis caused by the deposition of monosodium urate crystals in different joints around the body.
- Gout most commonly affects males, with men accounting for nearly eight in 10 total cases of gout.
- The first tarsometatarsal joint of the foot, more commonly referred to as the ‘big toe’, is the most common joint affected by gout.
- Gout is most commonly a monoarticular condition, meaning that it tends to only affect a single joint (‘mono’ = one). However, rarely more than one joint can be affected.
What causes gout?
- Gout is caused by high levels of uric acid in the blood. This is known as hyperuricemia. Uric acid is the breakdown product of purine within the body. Purine is an organic chemical compound that makes up the backbone of the DNA within our cells but is also found in many food and beverage products.
What happens in the body to cause gout?
- When there are high levels of uric acid circulating within the bloodstream, the acid activates the innate immune system.
- A series of complex immune reactions take place that result in the acid precipitating out as crystals. These crystals, known as monosodium urate crystals, then deposit in joints within the body.
What are the risk factors for gout?
As it is high uric acid levels in the blood that cause gout, and uric acid comes about from the breakdown of purines, anything that causes a high level of purines in the body can cause gout. A high level of purines can be due either to under-excretion or over-production/ over-consumption.
- Chronic kidney disease
- High blood pressure
- High cholesterol
- High intake of meat and/or seafood
- High alcohol consumption
- Consumption of high-fructose beverages
- Thiazide diuretics
- Low-dose aspirin
What are the signs and symptoms of gout?
Not everyone with high uric acid levels will be affected by gout. There are many people who have lots of uric acid circulating within the bloodstream but the acid does not form into crystals. In fact, hyperuricaemia is commonly asymptomatic. If you do happen to have symptoms of gout, the most common manifestation is an acute gout flare.
- Acute, sudden onset attack of severe pain in the affected joint
- The most common joint affected in the first metatarsal phalangeal joint, or the ‘big toe’. This is known as podagra. Other common joints affected are the ankles, knees and fingers.
- In addition to the pain, the affected joint is characterised by:
- Inability to walk due to pain
- Waking up at night due to pain
Less commonly, you may experience chronic gout which is known as tophaceous gout. This is characterised by:
- Tophi formation
- Tophi are painless, non-tender, hard nodules that may be yellow or white in colouration. They are caused by urate crystal deposition in and around the joints over a long period of time.
- The most common sites affected are the external ear, foot, knee and elbow.
- Joint deformities
Importantly, chronic tophaceous gout can result in complications for your kidney, such as kidney stones.
What is the natural history of a gout flare?
- In an acute flare of gout, the maximum pain severity is typically reached within 12-24 hours. The acute attack then takes a few days to several weeks to fully resolve.
- After resolution of an acute gout flare, you enter an ‘inter-critical period’ which refers to the time between gout flares.
- During this period, patients are asymptomatic, although monosodium urate crystal can continue to be laid down in joints without you noticing.
- The inter-critical period is of a variable duration but most people left untreated will experience another acute flare within two years.
What factors provoke an acute gout flare?
- Recent viral illness
- Consuming a large amount of purine-rich foods, such as red meat or seafood
- Binge alcohol drinking, including beer, spirits and wine
- Commencing certain medications, such as thiazine diuretics, loop diuretics, low-dose aspirin, cyclosporine, allopurinol
- Note: although allopurinol is the first-line treatment for chronic gout, it is contraindicated in acute gout flares
How is gout diagnosed?
- The gold standard for diagnosing gout is an analysis of the synovial fluid from the affected joint. This is known as an arthrocentesis and is done by your GP if there is clinical suspicion of a gout flare.
- The fluid will look cloudy and may appear paste-like in texture. In order to diagnose gout, the fluid taken from your joint is viewed under the microscope using polarised light. If you have gout, the monosodium urate crystals will be present in the synovial fluid from your affected joint and are said to be negatively infringement. This is 100% specific for gout and, it present, rules out all other diagnoses.
What are the treatments for gout?
Acute gout flares
There are four different options for medications to treat an acute gout flare. The choice of medication must be discussed with your doctor who, with your input, will make a decision about the best treatment for you. No matter which pharmacological agent is chosen, it should be commenced within the first 24 hours of experiencing symptoms and maintained for 3-5 days until the maximum severity of pain is reached and symptoms have resolved.
- Naproxen is a non-steroidal anti-inflammatory drug (NSAID) that is most often used as the first-line treatment because it has no adverse cardiovascular effects.
- Colchicine is second-line treatment for an acute gout attack and is used if NSAIDs are contra-indicated such as for patients with kidney disease or gastric ulcers.
- Systemic corticosteroids
- Oral prednisolone or intra-articular (injectable) methylprednisolone is used as a third-line treatment for a gout flare but should never be taken for long-term therapy due to its many side-effects with chronic use.
- IL-1 inhibitors
- Anakinra, rilonacept and canakinumab is fourth-line therapy and not generally used because of the limited evidence for their efficacy.
The aim of treatment of chronic gout is to reduce the likelihood of you ever having to experience an acute gout flare again and the excruciating pain that comes with it. There is a definite role for medication but you also have a role in terms of lifestyle modifications that will help reduce the risk of a gout flare.
- Weight loss, if overweight or obese
- Limit alcohol consumption, including beer, wine and spirits
- Reducing consumption of purines, such as red meat and seafood
- Reducing intake of high-fructose corn syrup, which is found in products such as sugary foods, juices and soft drinks
- Allopurinol is the first-line treatment to prevent acute gout flares. It is a urate-lowering therapy which, as the same suggests, acts by lowering the amount of urate within your body and hence reducing the likelihood of monosodium urate crystals forming.
- Allopurinol is generally started two weeks after resolution of an acute gout flare and continued indefinitely. Always follow the advice of your doctor when it comes to any medications.
- If possible, avoid medications that are associated with gout flares including:
- Thiazide diuretics
- Loop diuretics
- Low-dose aspirin
Note: there may be circumstances where the need for these medications to manage your other medical conditions outweighs the increased risk of a gout flare. You should always trust your doctor in making these decisions. For example, if you suffer from severe heart failure, you may be required to take thiazide or loop diuretics to manage this condition, and should always follow your doctor’s advice in regards to your medications.