Calcium pyrophosphate deposition disease (CPPD) is a type of arthritis. It is caused by deposits of calcium phosphate crystals in the joints and has similar characteristics to gout. A CPPD attack can occur suddenly and cause intense pain, inflammation, and disability.
CPPD is known by other names including pseudogout, an older term still used in many medical practices, and chondrocalcinosis is a related term that specifically refers to the calcium deposits that develop in the cartilage of joints.
With CPPD, the progressive formation of calcium in the joints can trigger occasional flare-ups of inflammatory arthritis symptoms including pain, stiffness, swelling, fatigue, low-grade fever, and restricted movement.
The risk of CPPD tends to increase with age. According to statistics from the American College of Rheumatology, the development of calcium crystals occurs in almost 3% of adults in their 50s. That number increases to nearly 50% by the time a person reaches 90.
Not everyone who develops CPPD crystal will experience symptoms. Of the 25% who do, most will have painful episodes involving the knees or experience pain and inflammation of the ankles, elbows, hands, wrists, or shoulders. CPPD attacks can last from a few days to several weeks.
CPPD attacks may be triggered by a severe illness, surgery, trauma, or extreme overexertion. Over the course of years, the disease can cause progressive deterioration of joints, resulting in long-term disability.
Around 5% of people who have CPPD will develop a chronic rheumatoid arthritis-like condition involving peripheral joints and affecting the same joints on different sides of the body, such as the wrists or knees.
The diagnosis of CPPD is often delayed because the symptoms are commonly mistaken for more common types of arthritis, including osteoarthritis, rheumatoid arthritis, and gout (a disease characterized by the formation of uric acid crystals).
The diagnosis will usually involve the aspiration of fluid from the affected joint and analysis of the crystalline deposits in the lab.
The doctor may also order imaging tests such as an ultrasound, a computed tomography (CT) scan, or a magnetic resonance imaging (MRI) scan to help identify calcified masses around the joint.
Unlike gout, in which the uric acid crystals can be dissolved with medications, the crystals involved in CPPD are insoluble (meaning they are unable to be dissolved).
Treatment, therefore, is focused on alleviation of symptoms and avoidance of future attacks.
Pharmaceutical options include:
- Nonsteroidal anti-inflammatory drugs (NSAIDs) to control pain and inflammation
- Low-dose Colcrys (colchicine), commonly used for gout, for people who are unable to tolerate NSAIDs
- Cortisone (steroid) injections into the affected joint to provide sustained, short-term relief from inflammation
- Plaquenil (hydroxychloroquine) or methotrexate (MTX) in more severe cases to temper the immune response and reduce inflammation
Surgery may be considered to remove a calcified mass from a joint, although it is still considered experimental, with limited data to support its use.