FEVER

Fever

 Fever is an ancient term means raised body temperature. Feverish is synonyms for fever. Pyrexia is come from greece word which means increased body temperature.

Normal body temperature- 98.6℉ or 37℃.

Apyrexia:-

  Absence of fever, normal temperature is below the normal body temperature.

Hyper pyrexia:-

  Elevation of body temperature above 106℉ produced by infection caused by micro-organisms.

 Highest temperature recorded - 114℉

 lower temperature recorded- 75℉

Cause:-

i. Infection (viral, bacterial, fungal, parasite)

ii. Infraction

iii. Severe hemorrhage (trauma)

iv. Inflammatory disease

v.  Occasionally a patient has an increased temperature continuously or intermittently called habitual hyperthermia.

vi. Heat stroke

vii. Injury to brain stem may produce fever

Mechanism-

  Fever is the result of breakdown of bacterial toxins liberated by the disease organism that affects the heat regulatory centers. (hypothalamus)

 Heat stroke is caused when heat or humidity are so extreme that the body can no longer cool itself sweating. Which is a major mechanism for loosing heat usually stopped.

         

                    Bacterial virus

                            ⬇release toxins

                  Exogenous pyrogen

                             ⬇ stimulate

                    Macrophages

                             ⬇ secrete

                 Endogenous pyrogen

                             ⬇

             carried in the blood to brain

                             ⬇acts on

           Heat regulatory center in hypothalamus

                             ⬇ 

             Temperature increased (pyrexia)

Symptoms:-

     Flushed face (redness), anorexia (loss of appetite), hot and dry skin, nausea and vomiting, constipation and diarrhoea, scanty and highly colored urine. Delirium is possible if temperature is over 105 degree F. Delusion (disturbed state of mind as restlessness illusion, incoherence)

Clinical representation:-

Clinically fever has 3 stages- Chill, heat, sweat.

   First is chill stage, as the temperature begins to rise, the body conserve the heat, the patient feels the cold. Cutaneous vasoconstriction reduces the loss of heat. The skin is dry often shivering or chill. The teeth chatters.

   Then comes the heat stage, this is peak stage of fever fall in the morning and rise in the evening. After cutaneous vasodilation develops it allows loss of excess heat, though sweating is uncommon the patient feels warm.

   Finally comes the sweat stage, it is also known as the stage of resolution. The heat center is reset, the excess of heat is lost mainly from skin. The patient feels not throws off the covering. 

 Cutaneous vasodilation and sweating is profuse.

Type of Fever:-

i. Intermittent fever

ii.Recurrent fever

iii Remittent fever

iv. Continuous fever

v . Undulent fever

i. Intermittent fever:-

    Any fever characterized by intervals of below normal temperature or touches the normal. Changeable temperature with great chill followed by heat and sweat with in 24 hours. Eg- Malaria.

ii. Recurrent fever:-

     Recurrent fever is also known as "Suppressive fever" or "Replacing fever". After 1-7days or week or a month again temperature rises. Normal person feels better but after a week or a month temperature rises. ie inflammatory conditions, typhoid.

iii. Remittent fever:-

   Fever is always above normal temperature cannot touch the normal level in 24 hours. eg- septicaemia, TB.

iv. Continuous fever:-

   Where the temperature remains above the normal temperature throughout a 24 hour period and do not fluctuate more than 1 ℃.

v. Undulent fever:-

    In this temperature rises after a month, 6 month, a year toxins does not suddenly removed. Eg- Malaria.