86 year old female with uti infection getting antibiotics body temp normal then a sudden rise 102.7 then goes down happens again next to2 days what can cause that?

Recurring fever: Thank you for your question. I would encourage you to be seen immediately. If you were being treated with oral or IV antibiotics for a serious infection and you have recurring fever, the origin of that fever needs to be determined. You need to have blood and urine cultures, sputum if you have symptoms. I would go to the ER tonight if I were you at age 86. Best of luck to you.