Pseudogout, also called CPPD disease, occurs when calcium crystals form in the joints. These crystals cause joint pain and swelling, and the condition is often misdiagnosed as gout or rheumatoid arthritis. Telling pseudogout vs gout can be tricky. So what is pseudogout, and what should we do about it? 

Pseudogout is closely related to — but distinct from — gout, which is caused by uric acid rather than calcium crystals.

What is pseudogout?

Pseudogout — calcium pyrophosphate deposition disease (CPPD) — happens when calcium pyrophosphate crystals build up in a joint and trigger sudden inflammation. As the name suggests, it looks like gout, but the crystal involved is different: calcium, not uric acid.

Symptoms 

Attacks of calcium pyrophosphate crystals cause sudden pain and swelling of a joint. The joints most often affected are the knees, ankles, and wrists, though the hips, shoulders, or elbows can be involved. An attack can last for days, and sometimes up to three weeks.

Although CPPD can affect people of any age, it usually affects people over 60.

How do we diagnose pseudogout?

You need a doctor to determine whether you have pseudogout or gout. The history, your medical background, and imaging all provide clues.

A pseudogout X-ray often shows calcification of the cartilage, called chondrocalcinosis. Ultrasound often shows bright calcium crystals in the middle of the joint cartilage. Some conditions, such as haemochromatosis (iron overload), can precipitate pseudogout, so we sometimes screen for these.

pseudogout

The joint fluid test is the gold standard.

In most cases, we confirm the diagnosis with a joint fluid test. We draw fluid from the affected, swollen joint and quickly send it to the laboratory to look for the characteristic rod-shaped calcium crystals.

Pseudogout vs gout: how can we tell?

It can be challenging to tell pseudogout vs gout, but there are clues:

  • Age and pattern: Gout typically affects men in their 50s and starts in a single joint, usually a toe or an ankle. Pseudogout affects older adults and can involve several joints, including the knees, wrists, and ankles.
  • Diet: purine-rich diets trigger gout, whereas pseudogout is unaffected by diet.
  • Duration: gout attacks usually last days, rarely weeks; pseudogout can last up to three weeks or more.
  • Crystals and imaging: on ultrasound, uric acid crystals coat the cartilage surface (a ‘double contour’ sign), while calcium sits in the middle of the cartilage. Under the microscope, uric acid crystals are needle-shaped, and calcium crystals are rod-shaped.

Treatment 

There’s no cure, and unlike gout, diet doesn’t affect how often attacks occur. So we focus on treating and preventing symptoms with medication.

For acute attacks, we suggest ibuprofen, colchicine, or steroid tablets — a recent study found colchicine and steroid tablets equally effective. In severe cases, a cortisone injection effectively controls pain and swelling in the affected joint, and we administer it under ultrasound guidance to improve accuracy and effect. Finally, surgery or joint replacement may be needed where there’s severe cartilage damage.

In younger patients who develop pseudogout, it is essential to exclude other possible causes such as haemochromatosis or rare bone diseases or hormone problems (PTH hormone abnormality). 

Frequently asked questions about pseudogout

Can calcium supplements cause pseudogout?

No. Although pseudogout involves calcium crystals, calcium supplements don’t trigger the condition.

Can diet changes prevent pseudogout?

There’s no evidence that dietary changes prevent pseudogout — unlike gout, it isn’t diet-driven. We still suggest weight loss and a generally healthy lifestyle.

Can you get gout and pseudogout together?

Yes. The two can occur together, and a joint fluid test can determine whether you have both.

Is pseudogout more serious than gout?

Neither is inherently more serious, but they’re managed differently — diet and uric-acid-lowering drugs help gout, while pseudogout relies on anti-inflammatory treatment. The main risk with both is misdiagnosis, especially mistaking one for the other.  

Which joints does it affect most?

Most often the knee, then the wrists and ankles — larger joints, unlike gout’s tendency to start in the big toe. This joint pattern is one clue that helps separate the two.

Final word from Sport Doctor London

Diagnosing pseudogout can be tricky, as its symptoms mimic other conditions such as gout and rheumatoid arthritis. See a doctor with expertise in diagnosing and managing crystal arthritis for an accurate diagnosis and the right treatment.

To book an assessment with Dr Masci in London, contact the team here or call +44 (0) 203 488 0350.

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