WebMD explains that fevers can be caused by infections, severe trauma or injury. Other factors that can cause fever are arthritis, hyperthyroidism and certain forms of cancer. Even certain medications can cause fever by specifically raising body temperature or by impairing the body's ability to regulate body temperature.
A high body temperature gone unchecked can lead to heatstroke, which is often considered to be a life-threatening medical emergency, warns WebMD. Any body temperature over 100.4 degrees Fahrenheit is considered to be a fever. If a fever persists or continues to rise, it is strongly advised to consult with a physician.