HYHO: Gout and Pseudogout Flashcards
Purines
PUR-DOUBLE-AG
- Adenine
- Guanine
Pyrimidine
- Cytosine (DNA)
- Thymine (DNA)
- Uracil (RNA)
How is uric acid formed in the body?
Degradation of purines (A,G) => produces uric acid.
Degradation pathway that forms uric acid
Inosine => hypoxanthine => xanthine => uric acid
What enzyme catalyzes the final 2 reactions in the formation of uric acid?
Xanthine oxidase
- Hypoxanthine => Xanthine via XO
- Xanthine => uric acid via XO.
Humans source of purines
- Diet
2. Nucleotide synthesis and breakdown
How do we excrete/get rid of uric acid?
- Kidneys (70%) via pee
2. Gut (30%) via poop
Too much uric acid can form what
MSU crystals
What is gout?
Intermittent painful, inflammatory joint attacks, in response to uric acid crystals due to hyperuricemia
RF for gout
- Males
- Older ppl
- Pacific islander
- HTN/hyperlipidemia/CV disease
- CKD
- Meds: Thiazides
- Diet (alcohol and red meat)
- Lead
Why is gout MC in men than women?
Estrogen increases the excretion of uric acid, making it less common in premenopausal W.
What meds increase risk of gout?
Thiazides
What foods/drinks increase risk of diet?
Alcohol and red meat
_______ = uric acid deposition in tissue
Gouty tophi
Hyperuricemia is due to what?
- Overproduction (hepatic metabolism and cell turnover)
2. Underexcretion (from mostly kidneys)
What is the main cause of hyperuricemia?
Underexcretion
Clinical presentation of gout
- Acute onset joint pain, most painful in 1st 24 hours that often begin at night.
- Joint = swollen, painful red and warm
Gout is MC in what joints?
- 1st MTP (podegra)
- Knee
- Ankle
Provoking factors for gout flare
- Alcohol
- Trauma
- Inflammatory states (infection, surgery, MI)
- Dehydration
Definitive diagnosis of gout
Arthrocentesis of joint’s synovial fluid
Send sample for: cell count, culture, and gram stain
_________ is used to look for monosodium urate crystals, which are
needle shaped, _____ birefringent crystals
Polarized light microscopy
negatively birefringent crystals