HESI Makeup Day Practice Test

Fever develops through a stepwise immune-driven process. First, a strong systemic immune response releases pyrogens (cytokines) into the bloodstream. These pyrogens travel to the hypothalamus and raise the hypothalamic set point. With the set point elevated, the body activates heat-generating mechanisms—shivering, increased metabolism, and vasoconstriction—to raise core temperature. After the pyrogens are neutralized or destroyed, the elevated set point begins to return to normal, and heat-dissipating responses such as vasodilation and sweating kick in to lower the temperature. This sequence—systemic response, raised set point, temperature rise, pyrogens destroyed, and heat loss responses—best fits the progression of a fever.