About Body Temperature

 

The human body is very adept at maintaining a normal healthy core body temperature in spite of wide variations in the environment.  Infection, disease, some drugs and significant exposure to extreme temperatures (heat or cold) can, however, cause significant or even life-threatening changes in body temperature.

 

Fever

 

The definition of fever is generally considered to be a body temperature above 38° C (100.4° F).  However, not all physicians even agree on this definition.  In some cases a body temperature >38° C is only considered significant it if persists for 2 or more days.[1] 

 

Fever can be caused by any of the following:

  • Infection, both localized and generalized;
  • Some medications whose side effects interfere with the body’s ability to adjust its core body temperature; this is referred to as drug-induced fever.
  • Certain disease processes or injury (e.g. heart attack, heat stroke, leukemia, lung cancer, etc.).

 

Fever is also one of the body’s defense mechanisms because it can make survival of an invading bacteria or virus more difficult.  For example, fever is commonly seen in post-operative patients during the first 48-hours but rarely indicates infection.  During this period the body is responding to the injury from during the surgical process and the beginning stages of healing, which includes inflammation of damaged tissues.

 

A high fever, however, can be dangerous leading to convulsions or even death.  Rapidly rising body temperatures in infants and children, usually under the age of 5, are more commonly associated with Febrile Seizures.  While the fever needs to be aggressively treated in these cases it is important to remember that brain damage rarely occurs with a body temperature under 107° F.[2]

 

Different types of fever –

 

Fever can be differentiated and described in several ways depending upon its onset and duration.  Some important terms to describe fever include:

 

  • Acute – characterized by a sudden onset and short duration;
  • Chronic – a slow, progressive and recurrent fever seen in some chronic disease conditions;
  • Recurrent – a fever which recurs, often due to failure to adequately treat the initial cause of the fever;
  • Continuous fever – characterized by an elevated body temperature that does not vary more than 1°C and never touches normal in a 24-hour period;
  • Remittent – characterized by an elevated body temperature that varies more than 2°C and never touches the normal level in a 24-hour period;
  • Intermittent – characterized by periods of both elevated and normal body temperatures within a 24-hour period.[3]

 

Treating Fever

 

A low-grade fever may not always require treatment and suppressing a low-grade fever may not be desirable because it is one of the body’s defense mechanisms against infection.  However, when the fever rises to such a degree that the individual becomes uncomfortable, treatment is usually indicated. 

 

Use of an anti-inflammatory, such as acetaminophen or ibuprofen may be helpful while the underlying cause of the fever is treated.  The use of aspirin is usually discouraged, especially in children, due to its association with the development of Reyes Syndrome in cases of viral infection.

Low Body Temperature

When the body’s core temperature drops significantly, it can become a serious, even life-threatening condition.  Low body temperature can be seen in conditions such as:

  • cold exposure,
  • shock
  • some metabolic disorders, such as diabetes,
  • alcohol or drug abuse,
  • overwhelming infections in those who may be frail or immune-compromised such as newborns or the elderly, and
  • gram-negative sepsis

[1] Body Temperature http://www.webmd.com/hw/health_guide_atoz/hw198785.asp, 1995-2006, Healthwise, Incorporated, P.O. Box 1989, Boise, ID 83701.

[2] Palo Alto Medical Foundation. http://www.pamf.org/children/common/fever/

[3] Chidambaranathan, S, MD, Treating Fever. Sept 13th, 2004, http://www.chennaionline.com/health/Homoeopathy/2004/09homoeopathy09.asp

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