Is it gout or pseudogout in my knee, and does the difference matter?

How they differ

• Crystal: gout is monosodium urate; pseudogout is calcium pyrophosphate, also called CPPD disease
• Who gets it: gout is more common in men from middle age and in women after menopause; pseudogout mainly affects people over 60
• Usual joints: gout favours the big toe, ankle and knee; pseudogout most often affects the knee and wrist
• Triggers: gout flares can follow dehydration, heavy meals, alcohol or sugary drinks; pseudogout can follow an illness, surgery or a knee injury
• Blood test: uric acid is often high in gout, though it can read normal during a flare; there is no equivalent blood test for pseudogout

How the diagnosis is made

The reliable way to tell them apart is to draw fluid from the knee and look at it under a polarising microscope. Urate crystals are needle-shaped; pyrophosphate crystals are shorter and rhomboid. The same sample is checked for infection, which can coexist with crystals.

An X-ray may show chondrocalcinosis, a fine line of calcium within the knee cartilage or meniscus, which supports pseudogout. In longstanding gout, X-rays can show erosions. Blood tests for uric acid, kidney function and sometimes calcium and other minerals help complete the picture.

Why the difference matters for you

The acute attack is managed in a similar way for both, usually with anti-inflammatory medicines, colchicine or a steroid, sometimes as an injection into the knee once infection is excluded.

Prevention is where they part. Gout can usually be controlled long term with medicines that lower uric acid, plus hydration, weight management and diet changes. Pseudogout has no equivalent crystal-dissolving treatment, so the focus is on treating flares, looking for associated conditions and managing any arthritis that develops alongside it.

Getting it checked in Doha

If your knee has flared without injury, especially more than once, it is worth establishing which crystal is responsible. At Aman Hospital Dr. Gelber examines the knee, can aspirate it in clinic, reviews the X-ray and works with your GP or a rheumatologist on long-term control when needed.