Acute Pseudogout (Calcium Pyrophosphate Dihydrate Crystals) Polarized light microscopy showing calcium pyrophosphate dihydrate crystals. Note the positive bifringence (blue) of rhomboid-shaped crystals versus the needle-shaped and negatively birefringent (yellow)...
Acute Gout (Monosodium Urate Crystals) Polarized light microscopy showing monosodium urate crystals. Note the negative birefringence (yellow) of needle-shaped crystals versus the rhomboid-shaped and positively birefringent (blue) crystals of crystal pyrophosphate...
Acute Gouty Arthritis Classic inflammation resembling cellulitis of the first metatarsophalangeal (MTP) joint, referred to as podagra. The first MTP is the most common site of initial involvement. (Courtesy Dr. A. Fam)
