Inflammatory Crystal Induced Arthritides: Gout, Pseudogout

Question 1

Gout
-pathophysiology
-risk factors
-presentation
-management

Answer 1

Prolonged hyperuricemia from purine breakdown => monosodium urate crystals in joint

Men 30-50s
Alcohol, meat, seafood
Loop, thiazides, CKD
Cytotoxics - myelo/lymphoproliferative malignancies

Intense pain, swelling, red, developing within hours
Big toe, ankle, wrist, knee
Tophi

Uric acid
-360+ - support diagnosis
-U360 - repeat uric acid level measurement at least 2wks after the flare has settled
Definitive - joint aspiration
-ve Birefringent needles of MSU

Acute - max dose NSAID until symptoms settle (alts colchicine => CS) + continue allopurinol if already using it
PPI if NSAID used

Maintenance - allopurinol
-when starting, use NSAID/colchicine cover to prevent acute flare
2nd line - febuxostat

Lifestyle
-reduce alcohol, avoid during acute attack
-weight loss
-avoid food high in purines
-CCB and ARB can be protective in HTN management

Question 2

Pseudogout
-pathophysiology
-risk factors
-presentation

Answer 2

Deposition of calcium pyrophosphate crystals in joint

• increasing age
• high PTH (high Ca)
• low Mg, PO4
  -haemochromatosis, Wilsons, acromegaly

Knee, wrist, shoulders

DEFINITIVE - joint aspiriation => positively birefringent rhomboid crystals, rule out septic
Xray - chondrocalcinosis is more specific

Acute - NSAID (alts colchicine => CS)