What is gout?
An inflammatory crystal arthropathy
What causes gout?
Deposition of urate crystals within a joint
Gout is usually as a result of what?
High serum uric acid levels
What is uric acid the final breakdown product of?
(formed in the DNA metabolism involving guanine and adenine)
Hyperuricaemia me be caused, or exacerbated by which factors?
- Renal underexcretion (of uric acid)
- Renal failure
- Excessive alcohol intake
- Diet (red meat, seafood)
What is the enzyme within the breakdown pathway of purines which can be acted upon by urate lowering therapies?
(Coverts hypoxanthine to xanthine to uric acid)
How is uric acid excreted from the body?
- Renal (2/3rds)
- GI (1/3rd)
Uric acid crystal precipitation in joints can be triggered by what?
Which joints can be affected by gout?
Most commonly the first MTP joint, ankle joint, knee joint
When gout affects the MTP joint, what is the name of this specific condition?
How does gout present and what does it mimic?
- Intensely painful
- Red, hot and swollen
May mimic a septic arthritis
What are gouty tophi?
Painless white accumulations of uric acid which can occur in soft tissues and occasionally erupt through the skin
If untreated, how long will symtpoms of gout last before resolve?
What can chronic gout result in?
Destructive erosive arthritis
Describe the process by which a definitive diagnosis is made for gout
A sample of synovial fluid is acquired via joint aspirate
The fluid is examined with polarised microscopy and also with a gram stain (to rule out infective arthritis)
Uric acid crystals are needle shaped and display negative birefringence (yellow to blue) when lined aross the direction of polarisation
What is the treatment for an acute gout attack?
- Opiod analgesics
When would colchicine be administered to a patient for an acute gout attack?
When the patient cannot take NSAIDs
What causes pseudogout?
Deposition of calcium pyrophosphate crystals within joints
What is the term used to describe when calcium pyrophosphate deposition occurs in cartilage and other soft tissues in the absence of acute inflammation?
Where does pseudogout tend to affect?
Which conditions does pseudogout commonly coexist with?
- Renal osteodystrophy
- Wilson's disease
Chronic calcium pyrophosphate deposition disease (CPPD) can result in which type of changes in joints?
What is the treatment for an acute attack of calcium pyrophosphate deposition disease?
- Corticosteroids (systemic and intra-articular)
What is the prophylactic treatment for calcium pyrophosphate deposition disease?
There is no such treatment