My husband is a heart patient. He has had a fever for about 48 hours. No other symptoms. In the mornings, his fever is low grade (99/100) and in the evenings his temp shoots up to 103. We took him to an urgent care place last night, they checked him out, throat, urine and nothing stood out as being a cause. Was told to drink plenty of fluids and take Tylenol. Today, his temp was really high about 3 hours ago - I gave him Tylenol and he rested. I just checked his temp again and it is 103.2 - we can't figure out why - no sore throat, no chills, - any suggestions?