Gout vs pseudogout

Gout is due to an accumulation of monosodium urate crystals

• Needle shaped
• Negatively birefringent
• Water soluble
• Taken up by polymorphs
• Can stimulate IL-1 (and an inflammatory reaction)

Pseudogout is due to accumulation of calcium pyrophosphate crystals

• Rhomboid shaped
• Positively birefringent