Calcium pyrophosphate dihydrate crystal deposition disease (CPPD) occurs when these crystals form deposits in the joint and surrounding tissues. The crystal deposits provoke inflammation in the joint, which can cause the joint cartilage to break down. The disease may take a few different arthritis-related forms: osteoarthritis, a chronic rheumatoid arthritis (RA)-like inflammatory arthritis, or an acutely painful inflammatory condition called pseudogout. The name pseudogout comes from the fact that it resembles another acutely painful condition called gout. The main difference is the type of crystals involved in the inflammation and damage.
In most cases, the cause of calcium pyrophosphate dihydrate crystal formation is unknown, although deposits increase as people get older. Almost half of people over 85 have the crystals, but many of them do not have symptoms. Because CPPD tends to run in families, genes may play a role. Other possible factors in its development include hemochromatosis, a condition when the body stores excess iron; low blood magnesium levels; and an overactive parathyroid or severely underactive thyroid.
About 25 percent of people with CPPD deposition will experience symptoms of pseudogout. Pseudogout comes in episodes, or attacks, that can arrive suddenly and last for days or weeks. It most commonly affects the knee. The affected joint may be hot, red, swollen, and stiff. Fever may accompany an acute attack. Damage to the joint progresses after years of these attacks.
About five percent of people with CPPD deposition will have a chronic rheumatoid arthritis-like condition involving several joints in a symmetric pattern (affecting the same joint on each side of the body, such as both wrists or both knees). Inflammation is low-grade as opposed to the intense swelling and pain of pseudogout. Similar to RA, this condition is characterized by morning stiffness and fatigue and can lead to joint deformities.
As many as half of people with CPPD deposition have osteoarthritis characterized by a progressive degeneration of several joints – most commonly the knees, followed by the wrists, metacarpophalangeal joints (where the finger attaches to the hand), hips, shoulders, elbows and ankles. The joints involved may become deformed over time. Degeneration may be more advanced on one side.
Because CPPD resembles other forms of arthritis, it is difficult to diagnose based on a physical exam alone. When CPPD is expected, doctors often use a joint fluid examination and X-rays to make the diagnosis. Other tests can help rule out other diseases.
For most people with CPPD, a combination of treatments can relieve pain and inflammation and improve joint function. Treatment varies with the different effects of the disease but for most people will include medications such nonsteroidal anti-inflammatory drugs or corticosteroids. For acutely painful and swollen joints, doctors may insert a needle into the affected joint to remove some of the joint fluid and then inject the joint with a numbing medication and a corticosteroid to decrease inflammation.
In addition to taking prescribed treatments, it is important to rest painful joints. Cold packs can help reduce the inflammation associated with flares or periods of intense inflammation.