In pseudogout, material deposited is

Ans: d (calcium pyrophosphate) Ref: Harrison 17th ed/p.2167.In Pseudogout, calcium pyrophosphate is depositedIn Gout, Monosodium urate crystal is depositedAssociations of CPPD (calcium pyrophosphate dihvdrate) crystal deposition:-* Ageing (most common)* Osteoarthritis* Familial* Metabolic diseases-HaemochromatosisHyperparathyroidismHypophosphatasiaHypomagnesaemiaWilson's diseaseCompensated polarised light microscopy of synovial fluids:-Monosodium urate crystals - Bright birefringence (negative sign) and needle shaped morphologyCalcium pyrophosphate crystals - Weak birefringence (positive sign) and rhomboid morphology.Note:-o Osteoarthritis- involvement of PIP, DIP and 1st carpometacarpal joint (base of thumb). Sparing of MCP and wrist.o Rheumatoid arthritis - involvement of any small joints of the hand i.e PIP, MCP, and wrist. Sparing of DIP.o Psoriatic arthritis - involvement of PIP, DIP, MCP and wrist. Sparing of any joint may or may not be present.