hyperpyrexia

/ˌhaɪpərpaɪˈrɛksiə/
noun
  1. An extremely high body temperature, usually above 106°F (41°C), caused by illness or infection.
    • Hyperpyrexia can be life-threatening and requires immediate medical attention.
    • Doctors treated the child's hyperpyrexia with cooling blankets and intravenous fluids.
    • The patient was rushed to the hospital with hyperpyrexia after collapsing from heatstroke.