Pyrexia of unknown origin Flashcards
When is body temp lowest/highest
Lowest in early morning
Highest in early evening - 4-6pm
Example of an endogenous pyrogen
cytokines released from host cells in response to infection
Example of an exogenous pyrogen
endotoxins of gram negative bacteria
Pyrogens do what to blood vessels
vasoconstriction –> decreased peripheral heat loss –> fever
Define PUI
- historical
- modern
Historically was temp >38.3 recorded on multiple occasions, present for at least 3 weeks
Nowadays, definition is much broader - if no diagnosis after 3 outpatient visits or 3 days in hospital
Types of PUO
Classical PUO
Nosocomial PUO
Neutropenic PUO
HIV-associated PUO
Causes of classical PUO
Infection Malignancy Inflammation Miscellaneous No diagnosis
Big causes of HIV-related PUO
Mycobacterium tuberculosis
Mycobacterium ovium
Unknown
Outline the approach to the PUO patient
History - travel, occupation, FH, PMH, DH, pattern of fever
Examination - skin, eyes, mouth, nails, lymph nodes
Initial investigations
Initial investigations for PUO
CXR Urinalysis FBC CRP/ESR Blood culture U&Es LFTs
Further specific investigations to do for PUO associated with tropical travel
Blood films
Further specific investigations to do for PUO associated with new murmur
ECHO
Further specific investigations to do for PUO associated with headache
Temporal artery biopsy
Contemporary imaging techniques available for use in investigating PUO
CT
PET
USS
Biopsy - temporal artery, bone marrow
Understand the place of the “therapeutic trial” in PUO patients
RARELY USED
-only really for suspected mycobacterial infection or connective tissue disorder
