IC17 Gout Flashcards
What are the RF of gout? (10)
RF:
- Alcohol
- Sugary beverages
- Red meat
- Sedentary lifestyle
- Obesity
- Male
- > 40y/o
- Genetics/renal disease (if male<30y/o & premenopausal women)
- HTN, diabetes, hyperlipidemia
- Drugs e.g. thiazide/loops, low dose aspirin, ciclosporin
What are the compartments of the immune system involved in gout?
Compartments of the immune system involved in gout:
- Innate immunity
o Phagocytes e.g. neutrophils and macrophages
Cytokine production
Adhesion and trafficking
o Cytokines & chemokines
What is gout and its patho? (may want to explain the normal physio 1st)
Gout
- Imbalances in purine metabolism (hyperuricemia)
- Deposition of monosodium urate crystals in articular & periarticular tissues
Normal physio:
Glutamine de novo synthesis → nucleic acids breaks down into
→ guanine & adenine
→ this can come from diet (purine rich food)
→ guanine, adenine & hypoxanthine can be recycled to be used as nucleic acid “salvage pathway”
→ hypoxanthine (then xanthine oxidase convert it into)
→ xanthine (then xanthine oxidase convert it into)
→ uric acid
→ excreted in humans
Patho:
- Overproduction of uric acid
a. Drug/diet-induced e.g.
i. alcohol,
ii. purine diet,
iii. fructose ingestion,
iv. cytotoxic drugs - Under excretion of uric acid (majority)
a. Drug/diet-induced e.g.
i. alcohol,
ii. diuretics,
iii. low dose aspirin,
iv. ethambutol,
v. nicotinic acid
- These leads to ↑[uric acid] → deposition of urate crystals in periarticular fibrous tissues of synovial tissues
- 1) Hyperuricemia → ppt of urate crystals in joints → complement activation → neutrophils chemotaxis → phagocytosis of crystals by neutrophils → lysis and activation of neutrophils → release lysosomal enzymes → tissue injury & inflammation
- 2) Hyperuricemia → ppt of urate crystals in joints → macrophages/monocytes phagocytose → release TNF, IL-1, IL-6 → release proteases → tissue injury & inflammation
- Positive feedback loop
Why is it that the most common location for gout to occur is the MTP of the big toe?
Uric acid
- Weak organic acid (pKa 5.75 in blood)
- Soluble in normal arterial pH of 7.4
- Solubility limit at 6.8mg/dL → ppt when > this [ ]
- Less soluble at lower temp (peripheral joints e.g. big toe)
What is the S&S of gout?
Recurrent acute gouty arthritis (urate crystals in synovial fluids)
Tophi (deposits of monosodium urate crystals in tissue & surrounding joints, white growth)
S&S:
- Monoarticular (1 joint at a time), mainly big toe (others: foot, ankle, knee)
- Pain
a. Rapid onset of pain at night
b. Excruciating Nocturnal pain, wake up from it
c. last several hrs - Tender, hot, swollen and red
a. Swelling and discomfort continues for days to weeks - Other problems: renal disease, kidney stones and Tophi
How to diagnose gout?
Diagnosis:
-
Presence of monosodium urate crystals in synovial fluid (Joint aspiration) & tophi (biopsy)
a. Yellow
b. Cloudy
c. ↓ viscosity
d. ↑WBC
e. No microbes
f. Crystals - S&S
- Hyperuricemia alone is NOT gout
- Further investigations: FBC, CRP, ESR, antibodies, xray
What are the goals of treatment for gout?
- SAFE & effective pain relief of acute gouty attack
- ↓future attacks (by ↓SU conc.)
When do you treat gout?
Out of these 4:
Asymptomatic Hyperuricemia
Acute gout (1st attack)
Inter-critical phase
Chronic Gout
- Acute gout (1st attack)
Features:
- Acute arthritis
- Typical 1st MTP big toe
- Excruciating pain
Medications:
- Colchicine
- NSAIDs
- Corticosteroids
- Chronic Gout
Features:
- Hyperuricemia
- Develop Tophi
- Recurrent attack of acute gout
Medications:
- Allopurinol
- Febuxostat
- Probenecid
see pg 56 of notes
How to treat acute flares? Give the dose.
If you are already on ULT, and an acute flare occurs can you continue it?
Acute flares:
- Treat asap (within 24 hrs)
-
(1st line) PO Colchicine loading dose 1mg, then 1hr later take 0.5mg (1 off treatment)
OR PO Colchicine 0.5mg BD/TDS daily till acute flare is resolved - (2nd line) Loading dose PO celecoxib 400mg, then 200mg BD for 5-7 days
OR PO prednisolone 30-40mg QD daily for 2-5days / till acute flare is resolved, then taper down for another 7 days by halving the dose then stop - Combination of colchicine + NSAIDs/coxib OR colchicine + prednisolone for 5-7days
- (3rd line) Intra-articular corticosteroids
- If already on ULT, continue ULT during flare
-
Ideally, start ULT 2-4wks after resolution of acute flare, but possible to start ULT during flares as well
o Risk of not returning
o Highly motivated to get prophylaxis
When to start ULT (criteria)?
When to start ULT (criteria):
- Frequent acute gout flares (2 or more per year)
- Tophi
- Gouty arthropathy
- Urolithiasis (kidney stones)
What is the treatment target when use ULT?
Treatment target:
- Non-tophaceous gout: <6mg/dL (<360umol/L)
- Tophaceous gout: <5mg/dL (<300umol/L)
How to start ULT?
Prophylaxis:
- Start low, go slow
- (1st line) PO Allopurinol 100mg/day, then increase to 300mg/day
- If CKD > stage 3 (<60mL/min), PO Allopurinol 50mg/day, then increase to 300mg/day
- (2nd line) PO febuxostat 40mg/day, if target <6mg/dL not met after 2-4wks, then 80mg/day
- (3rd line) PO Probenecid 250mg BD for 1 wk, then 500mg BD (drink a lot of water to prevent kidney stone formation)
+ PO Colchicine 0.5mg QD for 3-6 months
OR PO celecoxib 200mg QD / PO prednisolone 5-7.5mg QD
- Monitor Serum Urate, ADR, CI, DDI (ic13)
What is the non-pharm for gout during acute and long term phase?
Non-pharmacological management
- (During acute flare) Topical ice
↓flares - ↓alcohol
- ↓purine-rich foods
a. Red meat
b. Seafood
c. Ikan bilis
d. Peanuts, liver, cauliflower, durian - ↓high-fructose corn syrup
- Weight management
What’s the MOA of NSAIDs/coxibs?
What’s the place in therapy for NSAIDs?
NSAIDs e.g. naproxen, indomethacin
Coxibs e.g. celecoxib, etoricoxib
- Anti-inflammatory & analgesia
- inhibit PGE2 & urate crystal phagocytosis
Naproxen: BD dosing
Indomethacin: broader spectrum of anti-inflammatory action & similar to steroids can ↓leukotrienes action
Place in therapy:
- 1st line when >24-36hrs (symptomatic relief of pain)
Why does indomethacin have a broader spectrum of anti-inflammation?
Indomethacin: broader spectrum of anti-inflammatory action & similar to steroids can ↓leukotrienes action