Crystal deposition arthritides

Type of crystals found in gout and CPPD

Gout: monosodium urate

CPPD: calcium pyrophosphate dihydrate

1. What are the potential causes of Gout

underexcretion of Uric acid

1) diuretics and antibTB (ethambutol/ pyrazinamide)

2) obesity

3) dec renal function

4) genetic : mutation in URAT1 and ABCG2

Overproduction

1) red meat and seafood

2) Alcoholism

3) Psoriasis

4) Myelo and lymphoproliferstive disease

Chronic hemolytic anemia

Cytotoxic drug (calcineurin inhibitors, ethambutol, pyrazinamide)

Genetic variants

How much the incidence of normal uric acid level during flares

25%

Familial cause of CPPD

ANKH code for an anion transport of ATP and citrate, leading to an accumulation of inorganic pyrophosphate in the tissues. Another mutation associated with familial CPPD is TNFRSF11B.

How is made the diagnosis of gout

• Arthrocentesis gold standard: negative birefringent needle shaped

Acr eular classification criteria 2015 used in research

Treatment of gout

Acute flare:

Colchicine 1.2 mg then 0.6 mg after 1 hour, than bid for 3 days

Or nsaid , or prednisone 0.5 mg/kg/days over 5-10 days

Or anakinra 100 mg sc for 3 days

Continue ULT during attack

For chronic tt:

ULT +

Colchicine low dose for 3 months , or il 1 inh, or nsaids or steroids

What is the first line ULT and the dose

Allopurinol (xanthine oxidoase inhibitor)

Max dose 800

Titrate inc over 2-5 weeks

Risk of allopurinol hypersensitivity syndrome 10-25%

What are the risk factors to develop sensitivity to allopurinol

1) asians with HLAab5801

2) thiazide diuretics

3) pts allergic to penicillin and ampicillin

What is the second line tt of ULT

Febuxostat (nonpurine xanthine oxidase inhb)

Start with 40 mg, max dose 120

What are the other ULT

Pegloticase( recombinant uricase)

Probenecid

What is the major SE of pegloticase

Infusion reaction

Hemolytic anemia