fever patho.drjma

FEVER

BODY TEMPERATUREControlled by the hypothalamusnormal range of 36.5–37.5 °C (98–100 °F) Varieties of normal body temperature:

Temperature in the anus (rectum/rectal) is at or over 37.5–38.3 °C (100–101 °F)

Temperature in the mouth (oral) is at or over 37.7 °C (99.9 °F)

Temperature under the arm (axillary) or in the ear (otic) is at or over 37.2 °C (99.0 °F)

Normal body temperatures vary depending on many factors:AgeSexAmbient temperatureActivity levelTime of day

Low levels occur at 6 am: 37.2˚C (98.9˚F)Higher levels at 4-6 pm: 37.7˚C (99.9˚F)

Definition:An elevation of body temperature above normal range

due to an increase in the body temperature regulatory set-point. The increase in set-point is triggers increased muscle tone and shivering.A fever is one of the body's immune responses that

attempts to neutralize a bacterial or viral infection.Can be caused by many different conditions ranging from

benign to potentially serious.

Types:Continuous fever: Temperature remains above normal

throughout the day and does not fluctuate more than 1 °C in 24 hours.  Lobar pneumonia, typhoid, urinary tract infection, brucellosis,

or typhus. Typhoid fever may show a specific fever pattern, with a slow stepwise increase and a high plateau. (Drops due to fever-reducing drugs are excluded.)

Intermittent fever: Elevated temperature is present only for some hours of the day and becomes normal for remaining hours. Malaria, pyaemia, or septicemia. In malaria, there may be a fever

with a periodicity of 24 hours (quotidian), 48 hours (tertian fever), or 72 hours (quartan fever, indicating Plasmodium malariae). These patterns may be less clear in travelers.

Remittant fever: Temperature remains above normal throughout the day and fluctuates more than 1 °C in 24 hours. Infective endocarditis.

Pel-Ebstein fever: A specific kind of fever associated with Hodgkin's lymphoma, being high for one week and low for the next week and so on. However, there is some debate as to whether this pattern truly exists.

HyperpyrexiaFever with an extreme elevation of body

temperature greater than or equal to 41.5 °C (106.7 °F).Such a high temperature is considered a medical

emergency as it may indicate a serious underlying condition or lead to significant side effects.Intracranial hemorrhage (most common cause)Sepsis, Kawasaki syndrome, neuroleptic malignant

syndrome, drug effects, serotonin syndrome, and thyroid storm.

HyperthermiaHigh temperature that is not a fever.Occurs from a number of causes:

Heatstroke neuroleptic malignant syndrome malignant hyperthermia stimulants:

amphetamines cocaine idiosyncratic drug reactions serotonin syndrome.

Signs and symptoms

 Fever is usually accompanied by sickness behavior.LethargyDepressionAnorexiaSleepinessHyperalgesiaInability to concentrate.

Exogenous pyrogens(infectious agents,

toxins, tumors)

+

Monocytes, macrophages,

endothelialcells, other immune

cells

+

PGE 2

Antipyretics

NSAIDs

(-)

Anterior Hypothalamus

(+) Elevated Thermoregulatory set-point

Heat conservation(vasoconstriction,behavior changes)

Heat production(involuntary muscle

contractions)

FEVER

Management:Use of a fan or air conditioning may somewhat reduce

the temperature and increase comfort.Sponging or bathing feverish children with tepid water.Adequately hydration

ice pops juicenon-alcoholic drinks.

Medications:Antipyretic ibuprofen is effective in reducing fevers in

children.Acetaminophen (paracetamol)