Painful symptoms can occur when calcium pyrophosphate (CPP) crystals collect in the soft tissues of a joint and trigger an inflammatory immune system response, called pseudogout. These symptoms strike quickly and without warning.
Pseudogout most commonly affects 1 to 4 joints. It is less likely to cause pain in 5 or more joints.1 Any joint can be affected, most likely the knee, wrist, and/or large knuckles of the hand (metacarpophalangeal joints).1 The hip, shoulder, and spine can also be affected.1,2
Signs and Symptoms of a Pseudogout Attack
The typical signs and symptoms of pseudogout are described below. Note that although pseudogout symptoms normally resolve within several weeks, they should not be left untreated. Over time pseudogout can lead to permanent joint damage.
The most notable symptom of pseudogout is pain at the affected joint. If more than one joint is affected, it is possible for the pain to be more severe in one joint and moderate or mild in other joints.
Fluid can build up in the joint, causing noticeable swelling.
Read about How to Care for a Swollen Knee
Changes to the skin
As the joint becomes inflamed, the skin over the joint may appear red or purple (erythema) and may be warm to the touch. The skin may also appear stretched due to swelling.
Significant swelling and pain may make it difficult to bend and flex the joint. In addition to feeling stiff, the joint’s range of motion may be reduced.
Pseudogout can develop suddenly and without warning, taking 6 to 12 hours for pain and swelling to peak in severity.3 (In contrast, chronic CPP crystal arthritis has a more gradual onset, resembling osteoarthritis.1)
Fever and other flu-like symptoms
Pseudogout may cause a fever, chills, and/or other body-wide symptoms, such as a general feeling of being unwell. These inflammatory symptoms may be triggered as part of the immune system’s reaction to the calcium pyrophosphate crystals.
Duration of weeks or months
Left untreated, an episode of pseudogout can last days, weeks, or even months.1
Pseudogout Symptoms Differ from Gout Symptoms
While the immune system reactions that lead to gout and pseudogout produce similar symptoms, there are differences:
- Unlike gout, which often strikes in the middle of the night, pseudogout may occur at any time of day.
- While pseudogout pain can be severe, it is typically less extreme than the pain caused by an acute gout attack.1
- Recurrent cases of pseudogout do not result in tophi. Tophi (sing. tophus) are small white or yellow chunks of uric acid crystals that can be visible through the skin. They occur in people who have suffered from chronic gout for several years.
- An untreated episode of pseudogout can last several weeks or months. In contrast, an untreated episode of gout typically lasts a couple of weeks or less.
In addition, the symptoms of gout can have an obvious trigger, such as eating certain foods, drinking alcohol, or a change in medication. An episode of pseudogout is less likely to have a clear cause. Researchers are continuing to learn about the disease’s underlying causes and triggers.