Crystals of different substances can accumulate in and around the joints, leading to inflammation and pain. A buildup of uric acid crystals leads to gout, whereas calcium pyrophosphate crystals cause calcium pyrophosphate deposition (CPPD).
According to the American College of Rheumatology, gout affects more than 3 million people in the United States, while CPPD, previously known as pseudogout, affects 3% and 50% of those in their 60s and 90s, respectively.
Both gout and CPPD are types of inflammatory arthritis.
This article discusses what gout crystals are and the different types. It also looks at the medical treatment options and the steps people can take at home to reduce flare-ups.
Gout and CPPD are both inflammatory conditions that affect the joint. In both conditions, tiny crystals form in the joint and surrounding tissues. In some cases, they can deposit in other tissues as well.
These crystals cause inflammation of the joints, which can lead to pain and stiffness. The symptoms may be similar to those of osteoarthritis or rheumatoid arthritis.
Gout occurs when uric acid, or monosodium urate, builds up and forms crystals in the joints.
The crystals responsible for CPPD form when there is a buildup of calcium pyrophosphate in the cartilage. A painful episode of CPPD can happen when the body sheds crystals from the cartilage into a joint.
There are different types of gout crystals:
Monosodium urate, or uric acid, crystals
These crystals are responsible for gout. Uric acid is a waste product from the breakdown of purines, which are present in the body and in foods such as red meat, some seafood, and organ meats.
Usually, the kidneys filter out the excess uric acid. However, when there is an excess, it can build up and form needle-shaped crystals in the joints.
These crystals can rub against the synovium, which is the soft lining of the joint. This rubbing leads to inflammation, pain, and swelling. These symptoms often occur in the big toe, but they can also affect other joints in the body,
Calcium crystals are normally present in the bones and teeth. In people with CPPD, the crystals form in the cartilage.
In many cases, these crystals remain in the cartilage without causing any symptoms. However, the crystals can move into the joint cavity and rub against the soft tissue, causing pain and swelling.
Healthcare professionals refer to the movement of the crystals as crystal shedding.
CPPD crystals have a rhomboid shape with blunt ends.
Gout usually occurs in one joint at a time. A person experiencing a gout flare will have the following symptoms:
- intense pain
- redness, although this may only be apparent on light skin tones
Gout crystals usually affect the big toe, but they can also cause symptoms in the joints in the wrist, ankle, elbow, shoulder, knee, and hip.
CPPD has similar symptoms to gout and can lead to:
- severe pain and stiffness that comes on quickly and reaches its peak in 12–24 hours
- a fever, which can cause a person to sweat and feel generally unwell
The symptoms can last for a few days or up to 2 weeks.
Some home remedies that a person can try using include:
- Rest and cold treatment: Resting the joint as well as applying ice packs can help reduce pain and inflammation when someone is experiencing a flare-up.
- Weight management: Maintaining a moderate weight can reduce the likelihood of gout attacks occurring. Additionally, excess weight can lead to increased inflammation in the body.
- Exercise: Choosing low impact exercises can help reduce the amount of stress on the joints.
The uric acid that forms gout crystals is created when the body breaks down purines.
Foods that have naturally occurring high levels of purines include:
- red meat, including beef, lamb, and pork
- organ meat, such as liver, kidneys, and heart
- seafood, such as shellfish and oily fish
People who experience gout can consider trying to lower the amount of purine-rich food that they eat.
People should also avoid drinking alcohol and sugary drinks.
Medical treatments for gout attacks may include:
- Nonsteroidal anti-inflammatory drugs (NSAIDs): NSAIDs can help with both pain and inflammation of the joints. A person can take these within the first 24 hours of the gout attack to shorten the episode.
- Colchicine: This drug can help reduce some of the swelling and pain that a person may experience during a gout attack.
- Steroids: Corticosteroids, such as prednisone, methylprednisolone, and triamcinolone, may be beneficial for those who are unable to use NSAIDs. A doctor may deliver them via injection to a specific inflamed area, or they might recommend oral medication if the condition is affecting multiple joints.
There are no medications to dissolve CPPD crystals. However, a person can take NSAIDs and corticosteroids to reduce inflammation and pain. Colchicine can also help reduce the interaction between the crystals and the immune system.
A doctor may also insert a needle into the affected joint to remove the joint fluid. They can then inject a corticosteroid into the joint.
Once the initial gout attack has subsided, a healthcare professional may prescribe medications to reduce uric acid levels.
These medications include:
- febuxostat (Uloric) to reduce the amount of uric acid the body creates
- probenecid (Col-Benemid) to help the kidneys eliminate the uric acid
- allopurinol (Zyloprim), which also reduces the amount of uric acid the body creates
- pegloticase (Krystexxa), which can reduce the levels of uric acid quickly
A healthcare professional can administer pegloticase when other medications are ineffective.
It is possible that a person may notice an
With preventive medications, a person can completely dissolve any monosodium urate crystals and, therefore, stop gout from occurring in the future.
The time it takes for the drugs to eliminate the crystals can range between a few months and a few years.
At this time, there is no treatment that can dissolve the deposits of CPPD crystals in the body.
However, if a person experiences bouts of CPPD, a healthcare professional may recommend draining the synovial fluid to relieve pressure and reduce inflammation of the joint.
Surgery may also be an option if the joints become too damaged.
If a person is experiencing intense joint pain, they should contact a healthcare professional.
A person with fever and a joint that is painful and hot to the touch should seek immediate medical attention, as this combination of symptoms could indicate an infection.
A doctor may refer a person to see a specialist called a rheumatologist. The rheumatologist may diagnose gout or CPPD based on the symptoms a person is experiencing and the appearance of their joints. They may also carry out some tests, including:
- Joint fluid test: This test involves removing some of the fluid from the affected joint to look for crystals under a microscope.
- Blood test: The doctor may wish to check the levels of uric acid and other electrolytes, such as calcium, phosphate, and magnesium, in the blood. They will also measure kidney function.
- Ultrasound: These can help locate crystals within or around the joints.
- X-ray: This test can rule out any other causes of inflammation.
Gout and CPPD occur when crystals form and lead to joint pain and inflammation.
Gout crystals form due to a buildup of uric acid, while CPPD crystals form due to an accumulation of calcium pyrophosphate.
Both conditions can cause similar symptoms, including joint pain, swelling, and inflammation. The affected joint or joints will also be warm to the touch.
A person can treat gout and CPPD episodes using NSAIDS and ice packs. A doctor will likely also prescribe medications to help stop gout from reoccurring.
Although there is no way to dissolve CPPD crystals, draining the fluid around the joints can relieve pressure and inflammation.