Rheumatology: Crystal Arthroplasties Flashcards
Give a general definition of gout
Gout is a group of diseases where there is a tissue deposition of monosodium urate crystals due to hyperuricemia.
What’s the difference between gout and asymptomatic hyperuricemia?
Gout is an acute or chronic arthritis that arises as a result of MSU crystals whereas asymptomatic is exactly what it sounds like, you have elevated uric acid without any resulting symptoms.
What are the 4 stages of gouty arthritis?
1) Asymptomatic hyperuricemia
2) Acute gouty arthritis
3) Intercritical gout
4) Chronic tophaceous gout
What are the classic symptoms of acute gouty arthritis?
Usually it’s an abrupt onset of a red swollen joint, commonly the first MTP joint (termed podagra, like viagra but for a joint). They tend to resolve within 3-10 days. The common joints where this occurs are “cold” joints (more peripheral joints) because the crystals are less soluble there.
What’s intercritical gout?
This it the time inbetween acute attacks of gout
What are the clinical symptoms of chronic tophaceous gout?
You get subcutaneous, synovial, or subchondral deposits of MSU crystals on bone that form tophi, or bump like structures. Tophi are common on fingers/toes, the olecranon process, and the extensor surface of the forearm.
Is gout more common in males or females? When does it commonly occur in males? Females?
More common in males. In males, most commonly after the 3rd decade, most common in 5th decade. In females, more common after menopause. It occurs in about 2% of males and females in those age brackets.
Describe the typical synovial fluid findings in gout
The synovial fluid will have MSU crystals that are needle shaped and yellow. It will also show signs of inflammation, with 20,000-100,000 WBC/mm.
What is the major issue in terms of uric acid management in gout?
In 90% of cases, patients are UNDEREXCRETERS of uric acid (as opposed to over producers)
What percentage of filtered uric acid is normally excreted?
10%
What 2 mutations can lead to overproduction of uric acid?
1) Superactive PRPP synthetase
2) Deficiencies of HGPRT (complete HGPRT deficiency leads to Lesch-Nyhan syndrome)
Where are MSU crystals typically more soluble?
In warmer joints, just compare it to solubility in general. Things typically dissolve better in warmer solutions.
Why do the MSU crystals lead to inflammation?
They interact with the synovial lining tissues, such as mast cells and monocytes which promote inflammation. This process is dependent on PMNs. The crystals may also activate complement.
What kind of bases are associated with gout? How can the intake of these bases be modified to treat gout?
Purines. Foods such as shellfish and meats as well as alcohol can be decreased to try to decrease the chance of a gout flare up. However, diet isn’t too significant of a factor.
What is the best way to treat acute gouty arthritis?
NSAIDS
How should you treat chronic gout?
With specific anti-hyperuricemic drugs such as a uricosuric or a xanthine oxidase inhibitor
What demographic is at an increased risk of gout and what genetic marker should they have tested?
Koreans with stage 3 kidney disease and patients of Han Chinese or Thai descent.
They should be screened for HLA-B*5801
What is CPDD and how does it relate to pseudogout?
CPDD is an arthritis associated with the buildup of CPPD crystals in LARGE joints (like the knee).
Pseudogout refers to an acute flare up of CPDD.
T or F?
CPDD and gout both frequently involve the MTP joint
False. Only gout does. CPDD spares it.
T or F?
CPDD is strongly associated with rheumatoid arthritis
False. CPDD is strongly associated with concurrent osteoarthritis.
What are the classic characteristics of CPDD synovial fluid?
CPPD crystals in the fluid which are blue when examined. There should be anywhere from 2,000-80,000 WBC/mm
How does the formation of CPPD crystals differ from that of MSU crystals?
MSU crystals precipitate spontaneously whereas CPPD crystals are the result of cartilage matrix shedding, so those crystals are whatever the cartilage has shed off.
How is CPDD treated?
NSAIDS. Unlike gout, you can’t really remove the crystals.
What are common risk factors for gout?
Obesity, hypertension, and alcoholism
What cytokines are commonly released in gout?
TNF-alpha, IL-6, IL-8
What happens when MSU crystals engage the NLRP3 inflammasome?
IL-1beta production
