Final answer:
The fever from pyelonephritis usually starts to resolve within 2 to 3 days after starting antibiotics, but it is crucial to complete the full course of treatment.
Step-by-step explanation:
The fever associated with pyelonephritis generally will start to resolve within 48 to 72 hours (2 to 3 days) of initiating antibiotic treatment. However, it's important to continue taking the prescribed antibiotics for the full duration to ensure complete eradication of the infection and prevent resistance.
In some moderate to severe cases, symptoms including fever can recur several hours or days later, and other symptoms such as jaundice, rash, and confusion may persist for about 7 days. If a patient's symptoms do not improve within this time frame, further medical evaluation and potentially different antibiotic strategies based on sensitivity testing may be necessary.