Gout is a common type of inflammatory arthritis that causes sudden and severe swelling, pain, and stiffness in a joint. It typically occurs in the joint in the big toe. However, it also often affects the knee.
There exist more than 100 different types of arthritis and other related conditions that cause joint pain or disease.
In the United States, gout affects around 2% of the population.
This article discusses symptoms of gout in the knee, what causes gout, how doctors diagnose the condition, treatments, how to prevent it, and when to contact a doctor.
Gout of the knee causes inflammation in and around the knee joint.
It can also lead to inflammation in the prepatellar bursa in the front of the kneecap. Bursae are thin, slippery, fluid-filled sacs in the body that act as cushions between soft tissues and bones.
Symptoms of gout in the knee include:
- swelling in the knee and around it
- pain that is often sudden and severe and limits use of the knee
- change of skin color or shiny skin around the knee
- a warm sensation in or around the knee
- tenderness to the extent the joint cannot bear touch, weight, or pressure
- itchy, flaking, peeling skin as inflammation reduces
Symptoms of gout tend to come and go, worsening during flare-ups, which typically last 3–10 days.
After a first gout flare-up, it may be months or years before a person experiences another one. However, without preventive treatment, many people have another flare-up within 2 years.
Over time, gout flare-ups may affect more than one joint at a time and become more severe and frequent.
Gout occurs when uric acid levels in the bloodstream become too high.
If uric acid levels are too high for too long, masses called tophi may form in the joints or surrounding soft tissues. Tophi are white, chalky deposits that create visible skin lumps.
In most cases, proper treatment can prevent gout from becoming chronic.
It normally takes several years for chronic gout to develop. The condition can cause deformity, continuous pain, and permanent joint or soft tissue damage.
High uric acid levels in the blood can cause gout.
The body produces about 66% of uric acid naturally. Uric acid also forms when the body processes purines, which are organic compounds found in some protein-rich foods.
The kidneys usually help control the levels of uric acid by filtering it out of the blood.
Uric acid acts as a strong antioxidant that benefits the body at healthy levels. However, when there is too much of it in the bloodstream, it can lead to hyperuricemia.
This may occur if the kidneys do not filter out uric acid properly or if the body produces too much of it.
When a person develops hyperuricemia, excess uric acid may leave the bloodstream and form microscopic uric acid crystals in soft tissues or joints. These crystals may form around or in the joints because the temperature in these areas tends to be lower.
The immune system recognizes uric acid crystals as foreign particles, causing inflammation that looks and feels similar to that from an infection.
However, not everyone with high uric acid levels develops gout. Around 66% of people with hyperuricemia do not experience the condition.
Several factors seem to increase the likelihood of developing gout, including:
- Age and sex: Males are three times more likely than females to have gout. Males also typically develop gout between the ages of 30 and 45, while females tend to develop it after menopause, around the ages of 55–70.
- Certain medical conditions: Some diseases can increase a person’s risk of gout, such as:
- diabetes and metabolic syndrome
- kidney disease
- high blood pressure and high cholesterol
- some forms of anemia
- Lifestyle factors: Excess alcohol consumption can contribute to developing gout, as can diets rich in purine-containing foods and sugar.
- Medications: Certain medicines can increase the risk of gout, including:
- cyclosporine, which doctors use to treat autoimmune conditions
- diuretics and beta-blockers
- niacin, which doctors use to improve high cholesterol
- certain chemotherapy medications for treating cancer or autoimmune conditions
- Family history: People with a family history of gout are more likely to develop the condition.
A doctor specializing in arthritis, called a rheumatologist, will diagnose gout and help a person treat the condition.
To diagnose gout of the knee, a rheumatologist will physically examine the knee and the surrounding area. They will also ask questions about a person’s symptoms, diet, and lifestyle habits, as well as their personal and family medical history.
The doctor will then use some diagnostic tests to help confirm whether a person has gout or another condition. These may include:
- blood tests to measure uric acid levels during and in between flare-ups
- synovial fluid analysis, during which doctors examine a small amount of fluid from inside the joint for abnormal white blood cells, signs of infection, and uric acid crystals
- X-rays to rule out other joint conditions and examine and assess joint damage
- ultrasound scans to check for the presence of uric acid crystals
During a gout flare-up, treatment focuses on reducing pain by:
- taking over-the-counter anti-inflammatory or pain medications, such as naproxen and ibuprofen
- taking prescription medications, such as the extra-strength nonsteroidal anti-inflammatory medication indomethacin, corticosteroids, or colchicine, as soon as symptoms begin
- applying ice packs wrapped in a towel or cloth to the knee for 20 minutes at a time several times daily
- elevating the knee above the heart frequently
- resting the impacted knee as much as possible
- staying hydrated
- reducing or managing stress
- asking others for help when doing daily tasks
A doctor may also recommend using prescription medications, such as allopurinol, febuxostat, probenecid, or pegloticase, to lower uric acid levels and reduce the risk of further flare-ups.
Foods to limit or avoid
Cutting out or limiting foods that contain purines may help further reduce the amount of uric acid in the bloodstream and the risk of developing gout or experiencing gout flare-ups in the future.
Some foods rich in purines are the following:
- alcohol, especially beer and spirits
- certain meats, such as turkey, bacon, veal, liver, venison, and organ meats
- some types of fish and seafood, such as haddock, trout, scallops, cod, mussels, anchovies, sardines, and herring
Foods moderately high in purines include:
Other lifestyle habits
Adopting other lifestyle habits can also help decrease the risk of further gout flare-ups. These include:
- reaching or maintaining a moderate body weight
- exercising regularly, focusing on low impact exercises
- staying hydrated
- avoiding high fructose corn syrup and too much natural fruit sugar
- taking vitamin C supplements
- avoiding extreme diets, especially diets low in carbohydrates and high in proteins
- eating a healthy diet that reduces the risk of diabetes, high blood pressure, and obesity, such as one that includes a lot of fruits, vegetables, nuts, and plant proteins
People with joint damage or tophi from gout may require surgery.
People who are experiencing symptoms they think might be due to gout should seek guidance from a doctor.
Gout tends to progress and worsen over time. However, early treatment can often help control gout and reduce the risk of severe complications, such as joint damage.
People with gout can also develop infections, which they need to treat as soon as possible. Those who have diabetes are more likely to develop infections with gout.
A person should seek emergency medical care if signs of infection are co-occurring with symptoms of gout.
Gout is a common form of inflammatory arthritis that can often affect the knee.
Contacting a doctor as soon as symptoms of gout occur increases the likelihood of receiving proper diagnosis and treatment.
In addition, a person can manage gout by using home remedies and long-term preventive medications and adopting some changes to their lifestyle.