Pseudogout? What exactly is pseudogout? We typically divide inflammatory arthritis into the following categories: degenerative arthritis (i.e., osteoarthritis), autoimmune arthritis, arthritis caused by infections (septic arthritis), arthritis caused by cancer (neoplastic and paraneoplastic arthritis), and finally crystal arthopathy.
Pseudogout is a crystal arthropathy. Another common crystal arthropathy is gout. Like gout, pseudogout is very common, occurring in about 3.4% of adults. In fact, it’s the third most common cause of inflammatory arthritis.
What is pseudogout?
Pseudogout is a specific manifestation seen in calcium pyrophosphate deposition disease (CPPD). Basically, pseudogout is when CPPD flares up.
CPPD occurs when calcium pyrophosphate dihydrate deposits in cartilage and other parts of the joints. This leads to all sorts of possible symptoms. The following are just a few:
- Asymptomatic: You see it on x-ray, but you don’t feel it. This is actually quite common.
- Pseudogout: The joint is red, swollen, very tender, and sometimes people can have a fever. Often confused with gout or cellulitis. The knee and the wrists are commonly affected.
- Chronic CPP crystal arthritis: Typically many joints are involved. It can almost look like rheumatoid arthritis or polymyalgia rheumatica.
- Pyrophosphate arthropathy: This happens when people have severe osteoarthritis and then get superimposed pseudogout flares.
CPPD can also cause big deposits of crystals around the joints and bone. It can deposit on tendons, and can also involve the spine including the odontoid process. This is the part of the cervical spine that allows us to turn our neck from right to left and vice versa.
What’s the difference between pseudogout and gout?
Simply put, gout happens when monosodium urate crystals over-accumulate. Pseudogout is caused by calcium pyrophosphate crystals. This is why uric lowering medications like allopurinol or feboxustat, don’t work for pseudogout.
Who’s gets pseudogout or CPPD?
The vast majority of cases occur in people aged 55 years and above. In fact, if it occurs in someone aged less than 55 years, we need to look for other things:
- Primary hyperparathyroidism
- Hemochromatosis
- Hypomagnesemia (from diseases and medications)
- Hypophosphatasia
Other risk factors included dialysis-dependent renal failure and history of joint trauma or meniscus surgery. There are also familial forms. These genetic forms run in families and the first signs of the disease typically occurs in the person’s 20’s or 30’s. They also tend to affect the spine more.
What are the symptoms of pseudogout?
Pseudogout is an acute form of inflammatory arthritis. Look for warmth, redness, swelling, and pain. Sometimes, the joint and the skin looks infected. Sometimes people get a fever.
Usually pseudogout affects one joint at a time. But it can move around and affect more than one joint at a time. It likes the knees and wrists. However, if someone has “a bad” shoulder, pseudogout likes to go to “distressed” joints.
What triggers pseudogout?
Stress, infection, physical trauma, or a serious medical illness like a heart attack.
There are certain medications can cause a flare particularly those than decrease magnesium levels (e.g., certain forms of chemotherapy). Other medications include those that stimulate neutrophils as well as certain forms of intraarticular hyaluronic acid injections (e.g., Synvisc).
How do you diagnose CPPD?
The problem with CPPD is that it can cause arthritis without seeing it on x-ray. This happens in about 20% of cases. Consequently, the only way to 100% confirm CPPD is to pull fluid from the joint and test it for CPP crystals. Unfortunately, sometimes this isn’t possible. This is when the art of medicine really comes into play.
If possible, the joint should always be aspirated and tested. First, to confirm the diagnosis. Second, because the joint can also be infected at the same time. This happens in about 1% of cases. You don’t want to be the 1%!
Lab tests are not too helpful. There isn’t a specific test for CPPD or pseudogout. Inflammation levels are usually high including the CRP. Also about 10% of people have a positive rheumatoid factor. This is because advancing age is a risk factor for a positive rheumatoid factor. I encourage to read the article addressing this blood test in further detail. Please follow this link for further information.
How do you treat pseudogout?
If you do nothing, people typically get better on their own within 7 to 10 days. However, this is kind of brutal. Ice packs, rest, and removing the fluid from the joint may help. But, medications are often necessary. These include:
- Nonsteroidal antiinflammatory drugs (NSAIDs): ibuprofen, naproxen, diclofenac, etc.
- Steroid injection into the joint.
- Steroid injection into the muscle
- Oral steroid: typically tapered over 2 weeks.
- Colchicine can help
- In extreme situations we can use IL-1 blockers like anakinra or canakinumab. This is very expensive and not FDA-approved. I personally use this in rare and extreme circumstances.
The choice of treatment has to be tailored to each person’s medical conditions, allergies, medications, etc. No size fits all.
Can you prevent pseudogout flares?
Unlike gout, this is actually difficult to do. Sometimes colchicine or a very low dose of prednisone can help prevent attacks. You need to weigh the risks and benefits. Again, no size fits all.
If there is something that is predisposing someone to get flares… well address it if possible. For example, if a particular medication is decreasing your magnesium levels, see whether your doctor can replace the medication. If this is impossible, supplementing with magnesium could help. Remember to discuss this with your physician first. This is not medical advice.
Conclusion
I hope this information was helpful. If you would like to learn more about pseudogout, I invite you to follow this link.
References
Rheumatology Secrets, 3rd edition
Medical Disclaimer
This information is offered to educate the general public. The information posted on this website does not replace professional medical advice, but for general information purposes only. There is no Doctor – Patient relationship established. We strongly advised you to speak with your medical professional if you have questions concerning your symptoms, diagnosis and treatment.
