Fever is an increase in body temperature over an individual's normal temperature, which is typically considered above 100.4°F rectally. Fever is caused by pyrogens like bacteria, viruses, fungi or other pathogens that stimulate the immune system to produce endogenous pyrogens like interleukin-1, TNF, and interferons. Fever evaluation includes a medical history, examination to localize the source of fever, and determining the fever pattern and duration to identify the probable cause. Fever management involves environmental measures, hydration, and antipyretic drugs. Fever of unknown origin (FUO) is defined as fever over 38°C for more than 3 weeks without a diagnosis after initial investigations, and requires extensive

1. FEVER

2. WHAT IS FEVER ?
• Increase in body temperature over the normal
value of an individual
• Normal 97-100° F on rectal measurement with
diurnal variation
• Fever when rectal temp >100.4° F (38 °C)
oral temp > 99.5° F (37.5 °C)
axillary temp > 99 °F (37.2° C)
• Hyperpyrexia temp > 107 °F ( 41.5 °C)

3. Fever
Pyrogens ( bacteria, virus, fungi,
malignancy, connective tissue disorders , trauma )
Endogenous pyrogens  IL-1 , TNF ,interferons,
IL-6, IL-11,
stimulates
Exogenous pyrogens bacterial cell wall
components (LPS) , enterotoxins , exotoxins

4. EVALUATION OF FEVER
Detailed history
Clinical examination
Localize the fever to a particular system by
presenting complaints
 identify the probable etiology of fever
depending upon duration & type of fever,
clinical examination

5. Types of fever
• Continuous fever
• Remittent fever
• Intermittent fever (Quotidian ,Tertian, Quartan)
• Relapsing fever (Pel Ebstein fever)

6. Localizing the focus of fever
• Exanthematous fevers  rash, erythema, pustules ,
nodules
• URTI  cough, cold, throat pain, running nose,
dysphagia, earache, horse voice , stridor , regional
lymphadenopathy
• LRTI  cough, difficulty & fast breathing , wheezing,
crepitations, chest pain, sputum
• UTI (upper) pain abdomen,vomiting,renal angle
tenderness (lower)  burning micturition, urgency,
frequency, hematuria

7. • Hematological  pallor, bleeding spots , bleeding
from any site, lymphadenopathy, bone pain
• CVS  dyspnea, palpitation, pedal edema,
precordial pain & buldge, prominent neck veins
• Hepatobiliary  jaundice, vomiting, diarrhea, pain
abdomen, abdominal distension, hepato-
spenomegaly
• CNS  vomiting, headache, seizures, lethargy,
altered sensorium, neck rigidity, irritability,
abnormal tone, abnormal movement,

8. Etiology of fever
Short duration fever
• lasting for less than 2 weeks
• Usually due to infection (bacteria, viral, fungus,
protozoa)
Prolonged duration fever
• lasting more than 2 weeks
• Both infectious & non-infectious causes

9. Management of fever
Two methods of antipyresis
Non-pharmacological
• Environmental measures
• Hydration (fluids)
• Hydrotherapy (sponging)
Pharmacological therapy
• Drugs  paracetamol, ibuprofen,mefenemic acid

10. FUO
Definitions
Fever (rectal temp > 38° C) more than 3 weeks
duration documented by health care provider, for
which the diagnosis could not be established
even after 1 week of investigations in a hospital
setting.
Nosocomial FUO  pt developed fever after
hospital admission
Neutropenic FUO fever in a pt with ANC < 500

11. Etiology
• Infections
Enteric fever, TB, HIV, chronic hepatitis, occult
abscess, osteomyelitis, infective endocarditis ,
kala-azar , brucellosis
• Malignancy
Leukemia(AML,CML,ALL), Hodgkins lymphoma ,
NHL ,LCH
• Autoimmune
JRA , SLE , PAN , IBD, Kawasaki disease

12. Approach to FUO
• Evaluation of fever -- onset, type, duration ,
character, pattern, course of illness
• Clinical examination
• Laboratory tests
1st line – CBC, peripheral smear, malaria parasite,
widal, CXR , ESR , urine routine & cultute,blood
culture, mantoux test, LFT , RFT, USG abdomen,
special investigation depending on the clinical
clue

13. • 2nd line – HIV , CT chest and abdomen ,bone
marrow examination , 2D echo , dSDNA ,ANA ,RF,
complement levels, Ig levels,specific tissue biopsy,
serological tests for HBsAg , brucellosis, infectious
mononucleosis
• Usually possible to determine the etiology in most
cases
• In small number cases no cause is found. In such
cases periodic assessment is done .

14. Thank u
Fever is not a disease……… just a
symptom of the underlying illness
Treat the underlying disease not the
thermometer