A 70yr old female complain of swelling in knees with pain ,pain in both shoulder and back with cyanosis of distal fingers of left hand  What can be the cause of cyanosis ? No h/o injury  Inv.cbc,bs fasting .pp. Bt,ct  What else can I do for  the patient?

I gave antibiotics and analgesic to relieve pain. P.s.no pain in cynosed area mild  loss of sensation.