Belgorod National Research University

Project on Fever

Medical InstituteFaculty of General Medicine and Paediatrics

Department of Intermediate Surgery

Department of Head: Phd, MD, associate professor Kovalenko BS

Chief Practice: Phd, MD, associate professor Volkov DV

Tanya GargStudent of 1st yearGroup number: 03011420

Body Temperature Regulation

The temperature within the deep tissues of the body (core temperature) is normally maintained within a range of 36.0°C to 37.5°C.

Within this range, there are individual differences and diurnal variations: Internal core temperatures reach their highest point in late

afternoon and evening and their lowest point in the early morning hours.

Body temperature reflects the difference between heat production and heat loss. Body heat is generated in the tissues of the body, transferred to

the skin surface by the blood, and then released into the environment surrounding the body.

Body Temperature Regulation

The thermoregulatory center is in the hypothalamus and functions to modify heat production and heat losses as a means of regulating body temperature. The thermoregulatory center in the hypothalamus regulates the

core body temperature, not the surface temperature. This center integrates input from cold and warm thermal receptors

located throughout the body and generates output responses that conserve body heat or increase its dissipation = thermostatic set point. When body temperature begins to rise above the normal range,

heat-dissipating behaviors are initiated; When the temperature falls below the normal range, heat

production is increased; A core temperature greater than 41°C or less than 34°C usually

indicates that the body’s ability to thermoregulate is impaired.

Fever

Fever, or pyrexia, describes an elevation in body temperature that is caused by a cytokine-induced upward displacement of the set point of the hypothalamic thermoregulatory center.

Fevers that are regulated by the hypothalamus usually do not rise above 41°C - safety mechanism.

Fever can be caused by a number of microorganisms and substances that are collectively called pyrogens (many proteins, breakdown products of proteins, lipopolysaccharide toxins released from bacterial cell membranes, etc.). Some pyrogens can act directly and immediately on the

hypothalamic thermoregulatory center to increase its set point. Other pyrogens, sometimes called exogenous pyrogens, act

indirectly and may require several hours to produce their effect.

Causes of fever

Central type fever= neurogenic fever Non – central type fever:

Infectious disorders Noninfectious disorders:

Myocardial infarction Pulmonary emboli Neoplasms (e.g. malignant cells in leukemia, Hodgkin’s

disease produce pyrogens) Trauma Surgery

Neurogenic fever

It usually is caused by damage to the hypothalamus caused by: central nervous system trauma; intracerebral bleeding; an increase in intracranial pressure drugs (e.g. anesthetics)

Neurogenic fevers are characterized by a high temperature that is resistant to antipyretic therapy and is not associated with sweating.

The effects of fever

It enhance immune function; Increases motility and activity of the white blood cells; Stimulates the interferon production and activation of T cells;

Inhibits growth of some microbial agents: Many of the microbial agents that cause infection grow best at

normal body temperatures, and their growth is inhibited by temperatures in the fever range (the rhinoviruses responsible for the common cold are cultured best at 33°C);

Dehydration occurs because of sweating. May cause a febrile seizure, in children between the ages of 6

months and 5 years.

The effects of fever

Metabolic effects: Increased need for oxygen;

Increases the heart rate Increases the respiration rate

Increased use of body proteins as an energy source; During fever the body switches from using glucose (an excellent

medium for bacterial growth) to metabolism based on protein and fat breakdown;

With prolonged fever, there is increased breakdown of endogenous fat stores;

If fat breakdown is rapid, metabolic acidosis may result.

Types of Temperature Curves

Types of Temperature Curves1. Febris continua - permanent fever. Fluctuate between morning and evening

temperature do not exceed 1 °С. Such temperature curve is observed on the first period of abdominal typhus, crupose pneumonia.

 2. Febris remittens - indulgence fever. Fluctuate between morning and evening

temperature exceeds 1-2 °С. Such type of curve observes due to viral infections, sepsis, in second half of abdominal typhus.

 3. Febris intermittens. It is alternating fever. It is characterized that by the

rising periods of temperature (paroxysmuses) right alternate with the periods of normal temperature (apirrhexions). Temperature of the body rises to the level of 40 °С and higher, holds for a few hours, goes down to the norm and rises again. This fever type is observed in the malaria. The paroxysmuses can arise every fourth day (febris quartana), every third day (febris tertiana) or daily (febris quotidiana). Periodicity of the temperature rise depends on duration of development cycle of malarial Plasmodium. Paroxysmuses coincide in course of the time of erythrocytes destruction   (after completion of cycle).

 

Types of Temperature Curves4. Febris hectica. It is exhausting fever. Daily fluctuation of it is equal 3-4 °С and more. Sometimes

temperature goes down below the norm. Such fever is typical for sepsis, tuberculosis, malignant tumors. 5. Febris inverse. It is inverted fever. Maximum of the temperature is observed in the morning, temperature

decreases in the evening, sometimes to normal range. It is typical for sepsis and serious types of tuberculosis. 6. Febris recurrens. It is recurrent fever. There are periods of rising temperature (5-8 days) and normal

level of temperature (nonfever periods). Example is recurrent typhus, malaria. 7. Febris undulans. It is undulating fever. There is slow increasing of body’s temperature during some term

after that there its decreasing with period of normal temperature. It is typical for brucellosis. 8. Febris irregularis. It is irregular fever (atypical). It is characterize by nonright and different daily

fluctuations of the temperature. It is typical for chronic bronchitis, chronic cholycystites, rheumatism and leucosis. 

Types of fever Intermittent

Temperature returns to normal at least once every 24 hours; It is commonly associated with conditions such as gram - negative /

positive sepsis, abscesses, and acute bacterial endocarditis; Remittent

Temperature does not return to normal and varies a few degrees in either direction;

It is associated with viral upper respiratory tract, legionella, and mycoplasma infections;

Sustained or continuous Temperature remains above normal with minimal variations; It is seen in persons with drug fever;

Relapsing There is one or more episodes of fever, each as long as several

days, with one or more days of normal temperature between episodes;

It may be caused by a variety of infectious diseases, including tuberculosis, fungal infections, Lyme disease, and malaria.

Manifestations of fever

There are 4 successive stages - not all persons proceed through the four stages of fever development: 1. Prodrome

nonspecific complaints, such as mild headache and fatigue, general malaise, and fleeting aches and pains;

2. Temperature rises generalized shaking with chills and feeling of being cold; vasoconstriction and piloerection usually precede the onset of

shivering; skin is pale; when the shivering has caused the body temperature to reach

the new set point of the temperature control center, the shivering ceases, and a sensation of warmth develops.

3. Flush cutaneous vasodilation occurs and the skin becomes warm

and flushed; 4. Defervescence

the initiation of sweating.

Fever of unknown origin

It is defined as a temperature elevation of 38.3°C or higher that is present for 3 weeks or longer.

Among the causes are: malignancies (lymphomas, metastases to the liver and central

nervous system); infections such as human immunodeficiency virus or

tuberculosis, or abscessed infections; drug fever; cirrhosis of the liver.

Principles of treatment

Because fever is a disease symptom, its manifestation suggests the need for treatment of the primary cause.

Actions: modifications of the external environment intended to increase

heat transfer from the internal to the external environment; support of the hypermetabolic state that accompanies fever; protection of vulnerable body organs and systems; treatment of the infection or condition causing the fever.

Antipyretic drugs

Antipyretic drugs, such as aspirin and acetaminophen, often are used to alleviate the discomforts of fever and protect vulnerable organs, such as the brain, from extreme elevations in body temperature.

These drugs act by resetting the hypothalamic temperature control center to a lower level, presumably by blocking the activity of cyclooxygenase, an enzyme that is required for the conversion of arachidonic acid to prostaglandin E2.

Nursing care for patients with fever Monitoring body temperature: Frequent monitoring and assessment of

body temperature gives information about pattern, duration and course of fever. The aim of measuring body temperature in clinical practice is to estimate the deep body temperature, the core temperature.

A cool environment, exposure of the patient’s skin and sponge baths were medical recommendations.

Antipyretic drugs were introduced during the late 1800s and have since been commonly used.

ice water or cold water immersion should be avoided. Surface cooling should always be combined with antipyretic drugs to

prevent shivering Covering the extremities with cloth before lowering the temperature by

cooling, also prevents shivering