Overview
Pseudogout, also called calcium pyrophosphate deposition disease (CPPD), is a type of arthritis caused by tiny calcium pyrophosphate crystals that build up in joint cartilage and then trigger inflammation. It most often affects large joints such as the knee, and attacks can come on suddenly with intense pain and swelling. The inflammation can make the joint feel hot, stiff, and difficult to move, and it may limit how well you walk or bend the knee. With proper diagnosis and treatment, symptoms usually improve, though some people develop recurrent flares.
Symptoms
Symptoms commonly include sudden severe knee pain, swelling, warmth, and tenderness around the joint. The knee often becomes difficult to bend or bear weight on during an acute flare. Some people notice morning stiffness or reduced range of motion that can persist even after the worst pain settles. In some cases, symptoms can mimic gout or infection, so confirmation is important when a flare is severe or new.
Causes
Pseudogout happens when calcium pyrophosphate crystals form and deposit in the joint, especially in the cartilage and surrounding tissue. When those crystals shed into the joint space, they trigger an inflammatory response that rapidly causes pain and swelling. The exact reason crystals form is not always clear, but it is associated with changes in joint metabolism and certain medical conditions.
Risk Factors
Risk increases with age, because crystal deposition becomes more common over time. People with underlying metabolic or hormonal disorders, such as hemochromatosis or hyperparathyroidism, are at higher risk. Having existing joint damage or osteoarthritis can also make crystal deposition and flare-ups more likely. Family history may play a role in some cases.
Prevention
Because pseudogout involves crystal deposition, there is no guaranteed way to prevent every flare, but you can reduce recurrence risk by managing underlying medical conditions your clinician identifies. Staying well hydrated, maintaining a healthy weight, and using appropriate joint-friendly activity can help reduce stress on the knee. If you have frequent attacks, your clinician may recommend a long-term strategy such as low-dose anti-inflammatory medication for prevention. Avoiding known personal triggers during flares-like intense activity when symptoms begin-can also help.
How the Diagnosis Is Evaluated
Clinicians start with a history of sudden onset pain, swelling, and prior attacks, along with an exam of warmth, tenderness, and range of motion. A key step is joint fluid testing, usually by arthrocentesis, to look for calcium pyrophosphate crystals under a microscope. Imaging such as X-ray or ultrasound may show findings like chondrocalcinosis, but imaging alone cannot confirm the diagnosis. Blood tests may be used to support the evaluation and to help rule out gout or infection when needed.
Nonsurgical Treatment Options
During an acute pseudogout flare, treatment focuses on rapidly reducing inflammation and pain. Oral anti-inflammatory medicines such as NSAIDs are commonly used if safe for you, and colchicine may help in selected cases or early in the flare. Corticosteroids are another option, including oral steroids or an injection into the affected knee to calm inflammation quickly. Rest, ice, and temporarily limiting aggravating activity can help symptoms settle, while physical therapy or guided strengthening can support recovery and improve knee mechanics between flares. Managing contributing conditions, such as metabolic or hormonal disorders, may reduce the likelihood of future attacks.
When to Seek Medical Attention
Seek prompt medical attention if you have a new, very painful, hot, swollen knee, especially if you cannot bear weight or symptoms started suddenly. Go to urgent care or the emergency department if you have fever, feel very unwell, or if the knee swelling is rapidly worsening, because septic arthritis must be ruled out. Contact a clinician quickly if symptoms do not improve with home care within 24 to 48 hours, or if flares are recurring. Immediate evaluation is also needed if you develop numbness, major weakness, or sudden loss of knee function.
Frequently Asked Questions
Pseudogout is caused by calcium pyrophosphate crystals, while gout is caused by urate crystals, so joint fluid testing is often the most reliable way to tell them apart.
Yes, most flares can be treated conservatively with NSAIDs, colchicine, or corticosteroids, and many people improve with anti-inflammatory care and activity modification.
Next Steps
If you suspect pseudogout, especially for a first or severe flare, make an appointment with a clinician for an exam and, when appropriate, joint fluid testing to confirm the diagnosis and rule out infection. In the meantime, rest the knee and use ice while avoiding activities that worsen pain, and do not start high-risk medications without checking safety for your medical history. Seek urgent care if fever is present or you cannot bear weight.