What to Know About Calcium Pyrophosphate Crystals

Calcium pyrophosphate (CPP) crystals are microscopic, crystal-like formations that can accumulate in certain people’s joints, particularly older individuals.

While pyrophosphate is a naturally occurring chemical in the body, when it is coupled with calcium, the resulting crystal formations can collect in your cartilage and lead to a form of arthritis called calcium pyrophosphate dihydrate deposition disease (CPPD)—also known as pseudogout.

The sections below provide more information about this frequently misidentified condition, including its potential causes and the treatment options that are available.

What Are Calcium Pyrophosphate Crystals?

Our bodies produce the energy needed to fuel our daily tasks from a chemical called adenosine triphosphate (ATP). As we go about our daily activities and use ATP, a waste product called pyrophosphate is left over and is normally broken up or catalyzed by the body.

In some cases, however, too much pyrophosphate is produced or not enough is catalyzed. When this occurs, the leftovers can bind with calcium in the body and form calcium pyrophosphate crystals (CPP).

These microscopic rhomboid-shaped structures typically accumulate in the smooth, slippery cartilage that coats the ends of the bones in a joint. Unfortunately, the resulting crystal buildup can result in significant symptoms developing.

Complications

The accumulation of CPP in the body’s cartilage does not always cause issues; however, serious complications can arise in some cases. The sections below detail the most commonly seen problems that can occur as a result of this crystal buildup.

CPPD

One of the most frequent issues resulting from excess CPP crystal formation is calcium pyrophosphate dihydrate deposition disease (CPPD). This condition arises when the buildup of crystals in a joint’s cartilage irritates the area and causes sudden, sharp pain to occur.

This can also be accompanied by swelling or warmth, and the flare-up may last anywhere from a few days to several weeks.

CPPD’s symptoms closely mimic those of gout, and the two conditions are often confused. Gout, however, is caused by the buildup of a different type of crystal (called monosodium urate) and is treated as a separate disease.

CPPD usually causes sharp pain in the wrists or knees, though it may also impact the hips, shoulders, elbows, hands, feet, or ankles. In rarer instances, the second cervical vertebra is affected (referred to as crowned dens syndrome) and severe neck pain and a fever can develop.

Typically, CPPD impacts only one joint, though in some cases multiple areas may be afflicted simultaneously.

Asymptomatic CPPD

While CPP crystal buildup in an area can lead to the symptoms noted above, this is not always the case. In fact, most joints that show evidence of crystal accumulation on an X-ray are actually asymptomatic and are neither painful nor swollen.

Having no symptoms in spite of evidence of the disease on an X-ray is called asymptomatic CPPD. Interestingly, it is possible to have this form of the condition even if you have previously experienced acute pain from CPPD in other areas of your body. 

Chondrocalcinosis

People who undergo chronic bouts of CPPD may eventually experience physical changes within their affected joints. This process, called chondrocalcinosis, refers to the hardening or calcification of the smooth cartilage tissue.

While this condition can also occur as a result of aging or after a traumatic injury, it is frequently seen on an X-ray in the joints of individuals with CPPD. This finding is often thought of as a precursor to arthritis, though chondrocalcinosis itself does not always cause joint pain or swelling.

Joint Damage

As CPP crystals accumulate and cause acute pain, they can also accelerate the degeneration and breakdown of a joint’s cartilage. This process is known as osteoarthritis (OA).

While OA occurs frequently in older individuals, there is evidence to suggest that chronic CPPD can accelerate this process within an affected joint.

The arthritic damage from CPPD is most common in the wrists and knees, but can also be seen in the hands, feet, shoulders, elbows, and hips. In rarer cases, the joints in the spine may also be affected. 

Risk Factors

It is not always clear what causes CPP crystals to develop and accumulate within a joint. That said, there are several risk factors that can make CPPD more likely to occur.

One of the most common yet unavoidable risk factors is advanced age. It is estimated that up to 3% of people in their 60s and up to 50% of people in their 90s experience this painful condition.

Other individuals at greater risk include those with:

• Thyroid issues
• Parathyroid syndrome
• Low magnesium levels
• Kidney failure

In addition, disorders that affect the body’s ability to metabolize calcium, iron, or phosphate can also increase your likelihood of developing CPPD.

Diagnosis

Because the symptoms of CPPD can closely mimic those seen in several other diseases, proper diagnosis is the key to selecting an effective treatment. The most accurate diagnostic process is detailed below.

Laboratory Testing

Laboratory testing is needed to truly identify CPPD. To make a proper diagnosis, the synovial fluid from an affected joint is aspirated with a needle and the liquid is studied under a microscope. If the rhomboid-shaped calcium pyrophosphate crystals are present in the sample, then a positive diagnosis can be made.

Chondrocalcinosis is also commonly seen on the X-rays of individuals with CPPD. In spite of this fact, however, the presence of this radiographic finding should be considered supporting evidence and not the sole means of diagnosing the disease.

Diagnosis Difficulties

Differentiating CPPD from other conditions can be extremely challenging.

For example, gout is also caused by the buildup of a microscopic crystal (monosodium urate) in the body’s joints and can lead to sharp, debilitating pain in areas like the feet, knees, elbows, and wrists. Additionally, diseases like osteoarthritis or rheumatoid arthritis can also cause intermittent flare-ups of pain and swelling in one or several regions in the upper or lower extremities.

The many similarities between these diagnoses make it difficult to identify CPPD based on symptoms alone. Because of this, microscopic testing of the joint fluid in a laboratory becomes that much more important to accurately rule in the disease.

Treatment

From at-home options to skilled medical interventions, there are several treatments available to address the symptoms of CPPD. The sections below detail the most commonly utilized and effective choices.

Home Remedies

Early on after a flare-up of CPPD, following the RICE (rest-ice-compression-elevation) principle can help reduce the symptoms associated with this condition.

Immediately after you start to feel symptoms, take a break from any activities that cause increased pain and rest the affected area. Icing the joint can also help alleviate any pain or swelling by reducing inflammation. This can be done three or more times each day for 10 to 20 minutes per session.

Joint Drainage

While draining the joint fluid from a region is necessary to definitively diagnose CPPD, it can also help alleviate the disease’s symptoms.

This symptom reduction occurs because drawing fluid from the area, also known as arthrocentesis, reduces the pressure within the joint. This in turn can alleviate the pain associated with a CPPD flare-up.

Medication

Acute bouts of CPPD can be managed with several types of medication. These include:

• Corticosteroid injections: This is typically the first line of defense and can provide significant pain relief during a flare-up by reducing inflammation in the joint.
• Oral nonsteroidal anti-inflammatory drugs (NSAIDs): NSAIDs like ibuprofen or aspirin may also be utilized to decrease your inflammation. Unfortunately, these medications cannot always be taken by individuals with kidney or stomach issues, bleeding disorders, or heart disease.
• Colchicine: This medication can be taken orally to lessen the buildup of CPP crystals in a joint during an attack of the disease. This drug is frequently prescribed during a flare-up, but may also be given in lower doses on a long-term basis to prevent future attacks.

A Word From Verywell

CPPD is a condition that is difficult to properly identify and sometimes frustrating to deal with. Because of this, it is crucially important to work with a knowledgeable healthcare provider who has experience in treating this disease.

While you cannot always predict when a joint flare-up will occur, your healthcare provider can provide treatments to manage your symptoms and reduce the pain you are experiencing. Taking control of your CPPD is the key to minimizing the impact it has on your daily life!