1. Fever
2nd
commonest symptom
Thermostat- hypothalamus
Part of immune response

2. Definition
 Normal body temperature- 98-100° F
 Core/rectal > oral > axillary by 1° F
 Fever- regulated rise to a new thermoregulatory set-
point mediated by cytokines- IL-1, TNF, IL-6, IFN
 Hyperthermia- an increase in body temperature
over the thermoregulatory set-point, due to excessive
heat production &/or inadequate thermoregulation

3. Types
 Continuous- above normal throughout the day, with
fluctuation <1° F; e.g. viral fever
 Remittent- above normal throughout the day, with
fluctuation >1° F; e.g. IE
 Intermittent- touches normal during the day; e.g.
abscess, bacteremia, malaria
 Relapsing- short febrile episodes between day(s) of
normal temperature; e.g. malaria, typhoid
 Pel-Ebstein- relapsing fever with bouts of fever
lasting 3-10 days; e.g. Hodgkin’s

4. Causes
 Infection
 Inflammation- MI, PE, pancreatitis, polytrauma,
postoperative
 Connective tissue diseases- SLE, GCA,
rheumatic fever, Wegener’s, PAN, sarcoidosis
 Cancer- HCC/liver mets, RCC, lymphoma/leukemia,
atrial myxoma
 CNS- trauma or SOL
 Drugs

5. Pointers for infectious etiology
 Abrupt onset
 High fever +/- chills
 Systemic symptoms- malaise, myalgia
 Specific symptoms- productive cough,
dysentery, dysuria
 Tender LNE

6. Acute fever in OPD
 Viral- continuous fever, chills uncommon,
non-specific systemic symptoms
 Bacterial- intermittent fever, chills +, specific
systemic symptoms
 Malaria- relapsing fever, with chills/rigors,
non-specific systemic symptoms

7. Evaluation
History
&
Physical examination

8. Treatment
Treat fever- paracetamol, cold
sponging
&
Treat etiology/cause

9. PUO/FUO
Pyrexia/Fever of unknown origin

10. Definition- Classic FUO
 Fever >101° F on >1 occasion
 Undiagnosed despite
 3 outpatient visits
 3 days in hospital
 1 week of intelligent & invasive
ambulatory investigation

11. Definition- contd.
 Nosocomial FUO- undiagnosed fever in
patients admitted for at least 24 hours
 Neutropenic FUO- undiagnosed fever in
patient with ANC <500/uL
 HIV associated FUO

12. Important causes
 Tuberculosis
 Lymphoma
 Sarcoidosis
 Pulmonary embolism
 Infective endocarditis
 Abscess
 Drug-induced

13. Work-up
 History
 Physical examination
 CBC, LFT, TFT, urinalysis
 Blood cultures
 CxR
 Ultrasound abdomen
 CT scan- chest & abdomen
 Echocardiography
 Gallium-67 scan
 PET scan with radiolabelled FDG
 Bone marrow aspiration &/or biopsy
 Other serological tests- ANA, ADA, ACE etc.

14. Treatment
Wait till diagnosis, except
Urgent empirical antibiotics in
neutropenic fever