- The risk of CPPD greatly increases with age, but it can occur in young people, too.
- Proper diagnosis depends on detecting calcium pyrophosphate crystals in the fluid of an affected joint.
- CPPD may be hard to diagnose because the joint pain and other symptoms can mimic gout and other types of arthritis.
- Diagnosis is confirmed by using a microscope to see small calcium pyrophosphate crystals in joint fluid.
- Anti-inflammatory medications reduce pain and swelling and can prevent or help relieve symptoms of CPPD, but there is no way to get rid of the crystals.
Joint problems caused by crystals of a calcium salt called pyrophosphate may be one of the most misunderstood forms of arthritis. Joint problems seen with these crystals often are mistaken for gout and other conditions. Proper diagnosis (detection) is important. Untreated calcium pyrophosphate deposition (CPPD) may lead to severe, painful attacks or chronic (long-term) pain and inflammation. Over time, joints may degenerate, or break down, resulting in long-term disability. Some treatment options for the arthritis pain do exist, but these do not treat the underlying crystal deposits. Some of the underlying causes are treatable and should be evaluated in people with CPPD (see causes below).
What is CPPD?
CPPD is a type of arthritis that, as the old name of pseudogout suggests, can cause symptoms similar to gout. Yet, in CPPD, a different type of crystal, called calcium pyrophosphate, triggers the reaction. CPPD can cause bouts of severe pain and swelling in one or more joints, which can limit activity for days or weeks. It also can cause a more lasting arthritis that mimics osteoarthritis or rheumatoid arthritis.The condition most often involves the knees, but can affect wrists, shoulders, ankles, elbows, hands or other joints.
Crystals deposit in the cartilage (the tissue that cushions inside joints) and can damage the cartilage. The crystals also can cause inflammation that leads to joint pain, warmth and swelling.
In most cases, it is not clear why the crystals form, although crystal deposits clearly increase with age. Because the condition sometimes runs in families, genes likely play a role. Experts do not know how to prevent these crystals. If CPPD is due to some other medical problem, treatment of that condition may sometimes prevent CPPD from getting worse.
Other factors that can contribute to CPPD include:
- Excess iron storage (medical term: hemochromatosis)
- Low magnesium levels in the blood (hypomagnesemia)
- An overactive parathyroid gland (hyperparathyroidism)
- Some causes of excess calcium in the blood (hypercalcemia)
- A severely underactive thyroid (hypothyroidism)
Who gets CPPD?
The calcium pyrophosphate crystal deposits of CPPD affect about 3% of people in their 60s and as many as 50% of people in their 90s. The release of the calcium pyrophosphate crystals into the joint fluid can attract white blood cells, leading to a painful attack. Attacks of acute (short-lasting) arthritis can occur after injury to the joint, after surgery, or without a clear reason.
Calcium pyrophosphate crystals often are found in the cartilage and even synovial fluids of older people who have no symptoms. Many people who have these crystal deposits will never have acute gout-like attacks or chronic arthritis. These crystals also are often present in people with osteoarthritis or coincidentally in other types of arthritis such as gout or joint infections.
How is CPPD Diagnosed?
Diagnosis hinges on symptoms and medical test results. Imaging of the joint, including ultrasound, X-ray, CT, or MRI may help detect calcium-containing deposits are present in the cartilage. Your doctor must rule out other potential causes of symptoms. These include gout, rheumatoid arthritis, spondyloarthritis, and joint infection. Your doctor may use a needle to take fluid from a swollen or painful joint, to find out whether any other cause or calcium pyrophosphate crystals are present. Your doctor also may do blood tests.
How is CPPD Treated?
No treatment is available to dissolve the crystal deposits. For patients who have acute attacks, the doctor may prescribe nonsteroidal
anti-inflammatory drugs, which are commonly called
NSAIDs. NSAIDs, like indomethacin (Indocin) and naproxen (Naprosyn), treat pain and swelling during severe attacks.
People with poor kidney function, who have a history of stomach ulcers and/or who are on blood thinners often cannot take NSAIDs.
For these patients, it may help to have your doctor drain the joint fluid and inject a corticosteroid into the affected joint.
To try to prevent further attacks, low doses of colchicine (a medicine used more often for gout) or NSAIDs may prove effective.
Other medicines may help some patients during severe attacks of calcium pyrophosphate crystal arthritis or with the less common
chronic inflammation that these crystals can cause. These drugs include
methotrexate (Rheumatrex, Trexall, Otrexup, Rasuvo), or an “interleukin 1 beta antagonist”
that can decrease inflammation, such as the biologic medicine
anakinra (Kineret). Anakinra is approved by the government for treatment of rheumatoid arthritis.
Surgery to repair and replace damaged joints is an option in severe cases.
What is the Rheumatologist's Role in the Treatment of CPPD?
Rheumatologists are actively researching the causes of CPPD to better prevent and treat this form of arthritis. Because people with CPPD tend to be older and more prone to side effects from anti-inflammatory medications, they may benefit from seeing a rheumatologist, who can offer expertise in using such drugs and other therapies.
Rheumatologists are experts at detecting CPPD and directing a team approach to diagnosis of underlying conditions, treatment, and efforts to help prevent possible joint damage these crystals may sometimes cause. This team approach is important, because the patient may need advice about surgery or may need more information and support from other health care providers. These include physical and occupational therapists and nurses.
Updated December 2021 by the American College of Rheumatology Committee on Communications and Marketing.
This information is provided for general education only. Individuals should consult a qualified health care provider for professional medical advice, diagnosis and treatment of a medical or health condition.