A crystal-related arthritis that can resemble gout but is caused by a different crystal, and one where ultrasound helps reach the right diagnosis
CPPD, sometimes known as pseudogout, is a form of crystal arthritis. Like gout it is caused by crystals forming in a joint, but the crystal is a different type (calcium pyrophosphate rather than urate). It can cause sudden, painful joint inflammation, often in larger joints such as the knee or wrist, and is easily confused with gout, which is why an accurate diagnosis matters.
Written for patients and reviewed by Dr Liubov Borukhson, Consultant Rheumatologist (GMC 7021928).
CPPD can show itself in different ways. Common features include:
Diagnosis is based on the pattern of symptoms, examination, and where needed examination of fluid drawn from the joint, supported by imaging. Telling CPPD apart from gout and other causes of a hot, swollen joint is important, because the long-term management differs.
Ultrasound is particularly helpful here, as it can show the characteristic appearance of calcium crystals in the joint, helping distinguish CPPD from gout. Dr Borukhson uses point-of-care ultrasound during the consultation, so this can often be assessed in the same visit. You can read more on the ultrasound clinic page.
Treatment focuses on settling an acute attack with anti-inflammatory measures and, where attacks are recurrent, on reducing their frequency. Where a single joint is severely inflamed, an ultrasound-guided injection may help bring it under control. The plan is tailored to your situation and agreed with you.
Because CPPD is so easily mistaken for gout, confirming which crystal is responsible ensures the right long-term approach. If you have had episodes of a hot, swollen joint, a specialist assessment, with ultrasound where helpful, can establish the cause.
A specialist assessment, with ultrasound where helpful, can establish whether CPPD or gout is responsible and agree the right plan
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