FEVER
İstanbul University Cerrahpaşa
Medical Faculty
Department of Pediatrics
Prof. Dr. Ayşe Güler EROĞLU
The purpose of the lesson

Learning
The definition of fever
 The control mechanisms of body
temperature
 The circadian rhythm of body temperature
 Physiological factors that may increase body
temperature
 The pathogenesis of fever
 Normal and abnormal body temperature
 Etiologic classifications of fever
 Treatment of the fever (in high–risk patients)

Definition of fever

Fever is an elevation of body
temperature mediated by an
increase of the hypothalamic heat
regulatory set-point.
Control mechanisms of
body temperature

Hypothalamic
thermoregulatory
center controls body temperature by
 Peripheral
cold and warm neuronal
receptors
 Temperature of blood circulating in
the hypothalamus
Control mechanisms of
body temperature



Heat generation
 Increased cell metabolism
 Muscle activity
 Involuntary shivering
Heat conservation
 Vasoconstriction
Heat loss
 Obligate heat loss (evaporation,
radiation, convection, conduction)
 Vasodilation
 Sweating
Human is “homoioterm”
(has constant temperature)



Normal core body temperature 37o
C within a narrow range of 1-1.5o
C.
Axillary temperature may be 1o C
lower than core temperature cutaneous vasoconstriction
Oral temperature may be falsely
lowered
owing
to
rapid
respirations.
Circadian rhythm of
body temperature


Early morning temperature is low
Highest level occurs at 4.00-6.00
PM
Physiological factors may
increase body temperature






Physical activity (maximum 1.1o C)
Digestion
Changes in environmental
temperature
After ovulation in women
First three months of gestation
Exicement
Important



The body temperature
should be
measured
 at bed rest or physically inactive
for
30
minutes
before
the
temperature is taken
 within one hour after a meal
 prior intake of cold or hot foods
Before 6 years old - rectal or axillary
After 6 years old - oral temperature
measurement
Pathogenesis of fever


Various infectious, immunologic or
toxin-related agents (exogenous
pyrogens) induced the production
of endogenous pyrogens by host
inflammatory cells.
These endogenous pyrogens are
cytokines, such as interleukins (IL1, IL-1, IL-6), tumor necrosis
factors (TNF-, TNF-), and
interferon- (INF).
Pathogenesis of fever


Endogenous pyrogenic cytokines directly
stimulate to hypothalamus to produce
prostoglandin E2, which then resets the
temperature regulatory set point
Endogenous pyrogens induce fever
within 10-15 min. Whereas the febril
response to exogenous pyrogens has a
delayed onset requiring the synthesis
and release of pyrogenic cytokines (6090 min).
Normal
Low grade
fever
Rectal
36.1-37.8oC 38-38.9oC
Axillary
35-37.4oC
High grade
fever
39oC
37.5-38.4oC 38.5oC
Etiologic classification








Most common cause infections of the
upper respiratory tract.
A. Respiratory infections
1.
Common cold
2.
Sinusitis
3.
Pharyngitis: most frequent cause of
fever in childhood.
4.
Otitis media, mastoiditis
5.
Pneumonia
6.
Pulmonary tuberculosis
Etiologic classification








B. Urinary tract infections
C. Exanthemes
In the prodromal phase of exanthmatous
diseases.
D. Enteric infections
1.
Salmonellosis
2.
Campylobacter enteritis
3.
Ascariasis
4.
Amebiazis
Etiologic classification









E.
Infections of the central neural
system
1.
Meningitis
2.
Encephalitis
3.
Poliomyelitis
F.
Infections of the liver and biliary
tract
1.
Infectious hepatitis
2.
Cholangitis
3.
Liver abscess
4.
Granulamatous hepatitis due to
sarcoidosis,tuberculosis,hystoplasmosis,
brucellosis.
Etiologic classification









G.
1.
2.
3.
H.
1.
2.
3.
4.
Infectıons involving the heart
Rheumatic fever
Infective endocarditis
Myocarditis
Systemic infections
Bacteremia
Infective endocarditis
Infectiosus mononucleosus
Epidemic influenza
Etiologic classification









5.
6.
7.
8.
9.
10.
11.
12.
13.
Enterovirus infections
Cytomegalovirus infection
Psittacosis
Epidemic myalgia
Malaria
Toxoplazmosis
Tuberculosis in nonpulmonary form
Brucellosis
Others
Etiologic classification









I.
1.
2.
3.
4.
5.
6.
7.
8.
Abscesses, localized infections
Osteomyelitis
Intracranıal abscess
Lung abscess
Retropharyngeal abscess
Alveolar abscess
Perinephritic abscess
Appendiceal abscess
Pelvic abscess
Etiologic classification








9.
10.
11.
12.
13.
14.
15.
16.
Mediastinitis
Liver abscess
Subpherenic abscess
Spinal epidural infection
Purulant pericarditis
Empyema
Immunodeficiency diseases
Thrombophlebitis
Etiologic classification









II. Collagen-vascular or connective
tissue disease
A. Rheumatic fever
B. Serum sickness
C.
Dermatomyositis
D. Periarteritis nodosa
E.
Polyarteritis nodosa
F.
Lupus erythematosus
G. Juvenile romatoid artritis
H. Mixed connective tissue disease
Etiologic classification









III. Neoplastic diseases
A. Leukemia
B. Hodkin’s disease
C. Ewing tumor
D. Neuroblastoma with bone metastasis
IV. Dehydration
A.
Especially in newborn and young
infants
B. Hypertonic dehydration
C. Diabetes insipitus
Etiologic classification






V. Drugs, immunization
A. Disappears after 72 hours (after the
drug is stopped)
B. Immunuzation reactions
VI. Blood diseases
A. Hemolytic anemia, especially during
a crisis
B. Transfusion reactions
Etiologic classification





VII. Hemorrhage
A. If bleeding occurs into a viscus or
other body tissue in hemorhagic
disorders
B. Intracranial hemorrhage in the
newborn
C. Adrenal hemorrhage in the newborn
D. Hemorrhage into a tumor
Etiologic classification







VIII. Miscallenous causes
A. Kawasaki disease
B. Familial mediterranean fever
C. Takayasu’ arteritis
D. Virilizing adrenal hyperplasia
E.
Inflammatory bowel disease (Crohn
disease)
F. Others
Treatment


Other than providing symptomatic
relief, antipyretic therapy does not
alter the course of common infectious
diseases in normal children, and thus
its use is controversial in these
patients.
Antipyretic therapy is beneficial in
high-risk patients
 Chronic cardiopulmonary diseases
 Metabolic disorders
 Neurologic diseases
 Febrile seizures
Treatment







Acetaminophen
Aspirin
Nonsteroidal anti-inflammatory
agents (e.g., ibuprofen)
Aspirin - Reye syndrome
High dose acetaminophen - renal injury
and hepatic failure
Ibuprofen - dyspepsi, gatrointestinal
bleeding, reduced renal blood flow, and
rarely aseptic meningitis, hepatic
toxicity, or aplastic anemia
Bathing in warm water (not alcohol)
Hyperthermia


High body temperature not caused by
hypothalamic
thermoregulatory
mechanisms
Increased heat production
Vigorous exercise
 Malignant hyperthermia
 Neuroleptic malignant syndrome
 Hyperthyroidism


Decreased heat loss
Wrapping in multiple blanket layers
 Atropine intoxication
 Prolonged
exposure
to
high
environmental temperatures(heat stroke)

Malignant hyperthermia

Autosomal dominant disorder
 A history of drug exposure
 Previously affected family members
 Exposure the high environmental
temperatue
 Absence
of
the
hypothalamic
regulated circadian rhythm
 It also occurs in patients with various
myopathic disorders.
Neuroleptic malignant
syndrome

Occurs following exposure to
phenothiazine-like agents and is
indistinguishable from malignant
hyperthermia.