Fever By Larry M Bush, MD, FACP, Charles E Schmidt College of Medicine, Florida Atlantic University Reviewed / Revised Aug 2022 | Modified Sep 2022 View Patient Education Pathophysiology Etiology Evaluation Treatment Geriatrics Essentials: Fever Key Points Topic Resources Some Causes of Acute Fever Fever is an elevated body temperature that occurs when the body's thermostat (located in the hypothalamus) resets at a higher temperature, primarily in response to an infection.