Common biochemistry blood tests- uric acid Flashcards
1
Q
Uric acid
A
- End product of purine metabolism
- Excreted by kidneys (2/3rds) and hut hyperuricaemia caused by:
- Increase formation of uric acid e,g. cancer chemotherapy
- Decreased excretion of uric acid e.g. diuretics, often idiopathic; genetic or CKD
- Or combination of both
2
Q
Gout
A
- Severe joint pain of rapid onset
- Swelling and redness of joint
- Typically affects MTP joint of big toe
- Urate crystals in synovial fluid
- Serum urate variable
- First acute attacks usually subside within 5-10 days
- Normal uric acid doesn’t exclude: CRP and neutrophils are normally raised in gout
3
Q
Gout- complications
A
-Serum uric acid levels >360 mcmol/L are associated with increased risk for recurrent gout attacks
COmplications of gout are uncommon but can include
-Kidney stones
-Tophus formation
-Permanent joint damage
4
Q
Gout- Acute attack
A
- Relieving symptoms- acute attack
- Rest and elevated limb
- Keep joint cold
- NSAID
- If cannot take NSAID< colchicine (500mcg 2-4x day with max 6mg a day)
- If cannot take NSAID or colchicine, system corticosteroids
- IL-1 inhibitor
5
Q
Gout-preventing further attacks
A
- Maintain ideal body weight
- Restrict red meat and avoid high protein intake
- Avoid purine rich food- liver, kidneys and seafood
- Avoid dehydration (2L per day)
- Alcohol to a minimum
- Fizzy drinks containing fructose
- Exercise
6
Q
Gout preventing further attacks
A
- If >2 attacks per year or high risk
- Start allopurinol 1-2 weeks after inflammation settled
- Allopurinol is a xanthine oxidase inhibitor which prevents xanthine being converted into uric acid
- Titrate dose until SUA is <300mcmol/L
- Need to commence low dose NSAID or colchicine to cover first week of allopurinol, to prevent flare ups of acute gout
- Urosuric (probenisid)
- Febuxostat if allopurinol not tolerated/ COntra indicated
7
Q
Most common tests
A
- U&E
- LFT
- TFT
- Glucose
- BONE SCREEN
- Uric acid
- Cardiac enxymes
- ChE
- Haematology
