Stages of Fever:

There are 3 stages in fever:

• First stage:
  • In this stage, temperature of body rises as a result of spasm of blood vessels in skin
  • Ratio of heat production increases to heat loss.
  • This phase of rapidly rising temperature is accompanied by chills (feeling of cold) and shivering (rigors).
  • As internal temperature remains high, but extremities remains cold.
  • As result of shivering, there is more heat production due to spasm of muscles.
  • Chills are due to stimulation of cutaneous nerve endings following fall in body temperature caused by spasm of superficial blood vessels.
• Second stage:
  • In this stage, temperature remains highest
  • Ratio of heat production to heat loss remains at definite level
  • There is cessation of shivering
• Third stage:
  • In this stage, there is decline in body temperature.
  • Heat loss is increased compared to heat production
  • Heat loss occurs as profuse sweating or dilatation of blood vessels.
  • Body regains its normal temperature.