Fever is caused by an increase in heat production or a decrease in heat dissipation by the body due to various reasons. The clinical course of fever includes a first phase of rising body temperature, a second phase of hyperthermia, and a third phase of falling body temperature. Chills usually precede the fever, i.e. the period of rising temperature, and disappear during the period of hyperthermia. Fever with chills is commonly associated with various infectious diseases such as infectious respiratory diseases, malaria, acute pyelonephritis, septicaemia and acute suppurative cholangitis.