What is the Difference Between Gout and Pseudogout?

What is the Difference Between Gout and Pseudogout?
Gout and pseudogout sound very similar. What do they have in common?
 
Gout and pseudogout are both conditions in which substances that should be dissolved in the blood or body fluids becomes a solid chalky white material in tissues. Both of these conditions have the crystals that can build up in joints resulting in pain, swelling and possibly even joint damage. White blood cells called macrophages try to digest the crystals which causes them to release toxic chemicals causing inflammation. Conditions like these are called crystalline arthropathies, because they are joint problems (arthropathies) caused by crystals (crystalline). Normal joints do not have crystals in them. 
 
Does having pseudogout mean “kind of” having gout?
 
Gout and pseudogout, while both joint problems caused by crystals, are caused by different kinds of crystals.  Gout is caused by sodium urate crystals and pseudogout is caused by calcium pyrophosphate crystals. 
 
Who gets gout and pseudogout?  What are the causes?  Are the same joints affected?
 
Gout is most common in middle-aged men and usually starts in the large toe. This is called podagra.  The knee is the most common place for pseudogout to start.  Pseudogout tends to occur more evenly in men and women and usually occurs in older people.  Gout attacks can sometimes be caused by eating lots of red meat, particularly organ meats that are high in purines. Drinking certain types of alcohol, such as beer and distilled liquor may increase attacks. Wine does not seem to cause gout.  Pseudogout is not related to diet.  In both conditions, joints in the hand and wrist can be involved. 
 
How are gout and pseudogout diagnosed? 
 
The best way for your doctor to make the diagnosis is to draw fluid from an affected joint and look at it under a special microscope.  Gout and pseudogout crystals can be seen with the microscope and they look different when viewed in a special polarized light under a microscope. Gout crystals are shaped like a needle and are negatively birefringent. Pseudogout crystals are rhomboid shaped and positively birefingent. X-rays can also be helpful as they show different changes.  Gout eats away at the bones and joints of the hand and wrist. There may be many small cystic erosions in the bones at the joint surfaces.  Pseudogout may be seen on x-ray due to the calcium crystals depositing in the soft tissues around the joints.  Blood levels of urate are often elevated in gout but are normal in pseudogout. 
 
What else can be confused with gout and pseudogout? 
 
Fractures, infection, osteoarthritis and other inflammatory problems such as rheumatoid arthritis can be confused with gout and pseudogout.  Your hand surgeon can help tell these conditions apart and ensure you get the right treatment. 
 
How are gout and pseudogout treated?  Are they treated the same? 
 
Treatment differs and that is why getting the right diagnosis is important. In both cases, steroid injections (cortisone shots), anti-inflammatory medications and colchicine may be useful.  For gout, your medical doctor may prescribe a mediation that decreases urate and may also recommend diet changes to keep gout from coming back. 
 
I think I have one of these problems!  How can I find a hand surgeon to help me? 
 
Please check out the Find a Hand Surgeon tool from the American Society for Surgery of the Hand to find a hand surgeon near you.
 

Ryan Zimmerman, M.D. is a Hand, Shoulder and Elbow Surgeon in Baltimore, Maryland.  He is a member of Greater Chesapeake Hand to Shoulder and an Attending Surgeon at the Curtis National Hand Center.
 
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