Definition

Pseudogout, also known as calcium pyrophosphate deposition disease (CPPD), is a type of arthritis caused by the accumulation of calcium pyrophosphate crystals in the joints. It is called pseudogout because its symptoms are similar to gout, another form of arthritis caused by the buildup of uric acid crystals in the joints.

Pseudogout typically affects the knees and wrists. However, calcium pyrophosphate crystals can occasionally accumulate in other joints, such as the hips, shoulders, elbows, knuckles, or ankles, causing discomfort. This discomfort can lead to limited mobility for those affected.

Causes

Risk Factor

Underlying Medical Conditions

Pseudogout frequently occurs in individuals with hyperparathyroidism (excess parathyroid hormone). Although the exact mechanism is unknown, it is thought to be related to excess calcium and phosphate production mediated by the parathyroid hormone. This hormone controls blood calcium levels, and an excess can lead to increased calcium production, potentially triggering the formation of calcium deposits in bones or joint spaces.

Other conditions that increase the risk of pseudogout include:

• Gout, a form of arthritis caused by the buildup of uric acid crystals
• Osteoarthritis, a condition that affects multiple joint tissues due to inflammation
• Rheumatoid arthritis, an inflammation of the joints and surrounding bones caused by an autoimmune response against healthy joint cells
• Hypomagnesemia, a condition in which magnesium levels in the blood are lower than normal
• Osteoporosis
• Chronic kidney disease
• Excess calcium supplementation

Advanced Age

The risk of pseudogout increases with age. Most patients experiencing crystal buildup in their joints are over 65 years old. Studies have shown that between 30% and 50% of patients over the age of 85 experience this condition. CPPD or pseudogout is rare in individuals under 60 years of age and is often associated with degenerative diseases such as osteoporosis in older adults.

Joint Trauma

A history of joint injury or abnormalities after surgery can increase the risk of pseudogout. In areas with inflammation, the risk of calcium pyrophosphate crystals forming in the cartilage may increase.

Genetic Abnormalities

Some studies link pseudogout to genetic abnormalities, with the condition sometimes inherited from affected parents. This is more commonly seen in younger patients diagnosed with pseudogout.

Mineral Imbalances

Pseudogout results from calcium buildup in cartilage and joints. Individuals with excess calcium or iron in their bodies, either due to certain medical conditions or over-supplementation, are at risk of developing this condition. On the other hand, those with insufficient levels of other minerals like magnesium may experience elevated calcium levels in the blood, which could contribute to the development of pseudogout. Imbalanced mineral levels in the body can increase the risk of this disease.

Symptoms

Patients experiencing acute arthritis attacks due to calcium pyrophosphate buildup may present with symptoms similar to acute gouty arthritis caused by uric acid accumulation, such as:

• Joint swelling
• Redness around the affected joint area
• Joint pain

Up to 50% of pseudogout patients may also experience chills. The most commonly affected joint is the knee, followed by the hips and shoulders. Some patients may also experience acute symptoms after a joint injury.

Patients with long-standing pseudogout often report mild joint pain. This pain may be felt in joints that do not bear weight, such as the wrists and finger joints.

Diagnosis

Diagnosing pseudogout involves a combination of medical history, physical examination, and diagnostic tests. Informing your doctor of any underlying conditions, such as hyperparathyroidism or other risk factors is essential. The doctor will ask about your symptoms and examine the affected joints.

To confirm the diagnosis, joint fluid may be collected from the inflamed joint and analyzed. This procedure is called arthrocentesis or joint fluid aspiration. Additionally, imaging tests including:

• CT scans or X-rays of the affected joint
• Ultrasound of the cartilage
• MRI to evaluate the extent of calcium crystal buildup in the cartilage and joints may be used

Management

Currently, there is no specific treatment that directly targets calcium pyrophosphate crystal buildup. Treatment focuses on reducing inflammation and stabilizing underlying metabolic conditions, such as hyperparathyroidism. In patients with acute inflammation affecting 1-2 joints, joint fluid aspiration may be performed to reduce joint pressure and relieve pain. Corticosteroids such as betamethasone or dexamethasone can also be injected into the joint to reduce inflammation.

For patients with acute inflammation affecting three or more joints, systemic treatment (functions throughout the body) is usually provided with nonsteroidal anti-inflammatory drugs (NSAIDs).

At home, you can apply cold compresses to the affected joint, rest, and limit movement to reduce inflammation.

Complications

Calcium pyrophosphate crystals can trigger inflammatory responses. One potential complication is the calcification of cartilage (chondrocalcinosis). In rare cases, patients may develop palpable, hard nodules in the joint tissue due to calcium crystal accumulation, which can lead to joint deformity.

Prevention

Preventing pseudogout primarily involves managing modifiable risk factors. If you have a history of hyperparathyroidism, maintaining regular treatment can help prevent conditions associated with calcium imbalances, including pseudogout. A balanced diet that ensures sufficient intake of essential minerals, such as calcium and magnesium, is also recommended

When to See a Doctor?

Acute symptoms, such as joint pain caused by calcium phosphate crystal buildup, can significantly disrupt daily life. If you experience these symptoms, seek medical attention for appropriate treatment.

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