Lupus is something that your sister has most likely had for many years, yet it has been dormant in your body. I have read may books and articles that state the body can trigger the Lupus from a dormant state by going through a tramatic event, such as surgery, a stressful situation, like a divorce or death of a loved one, a serious virus or infection in the body, you get the idea.
Here is some info I found on the Lupus Foundation of America website. http://www.lupus.org/webmodules/webarticlesnet/templates/new_about
The cause(s) of lupus is currently unknown, but there are environmental and genetic factors involved. Some environmental factors which may trigger the disease include infections, antibiotics (especially those in the sulfa and penicillin groups), ultraviolet light, extreme stress, certain drugs, and hormones.
Scientists believe there is a genetic predisposition to the disease, as lupus is known to occur within families. However, there is no known gene or genes which are thought to cause the illness.
Most likely the infection or the surgery itself from the gallbladder surgery could have triggered your sisters disease.
Lupus - 1997 Fibro - 2001 Sjorens - 2007 Raynauds - 2008
Plaquenil, Imuran, Prednisone, Synthroid, Topomax, Effexor, Norco, Prilsec, Xanex, Elidel, Restasis