What would be your differential for a wrist monoarthritis in an elderly female with erosions on MRI after less than 3 months of symptoms?  

I would put CPPD arthritis high on the differential, as the wrist is a common site for CPPD arthropathy in the elderly. In the right context, septic arthritis is a possibility, particularly if the patient is immunosuppressed. Indolent infections such as fungal or mycobacterial are possibilities. Les...