Lecture 4 Pyrexia of Unknown Origin Flashcards
What is a fever?
An elevation of body temperature above normal (37C)
What are pyrogens
Substances which cause fever
Name an endogenous pyrogen
Cytokines
Name an exogenous pyrogen
Endotoxins from gram negative bacteria
Petersdork and Beeson definition of PUO
o Temp >38.3C
o Recorded on multiple occasions
o Present for at least 3 weeks
o Defied diagnosis after one week of hospital evaluation
Modern definition of PUO
o 3 outpatient visits or
o 3 days in hospital or
o One week of outpatient investigations
What is Nosocomial PUO
Develops in hospital, undiagnosed after 3 days
What is neutropenic PUO
Undiagnosed fever in patient with neutrophils <500/mm3
What is HIV-associated PUO
Fever in a patient with HIV infection- present and undiagnosed for more than 3 days in an inpatient or four weeks in an outpatient
Mycobacterium tuberculosis
What are the initial investigations
o CXR o Urinalysis and urine microscopy o FBC and WCC o CRP and ESR o Blood cultures taken at times of fevers o Urea, creatinine, electrolytes, LFT
If patient had tropical travel what further investigations would you do
Blood for malarial parasites, Dengue, HIV, bone marrow for leishmaniasis. Less likely if >21 days since return
If patient had a new murmur what further investigations would you do
ECG (transoesophageal echo may be needed) for vegetations
If patient had headaches what further investigations would you do
Temporal artery biopsy (TA)
If patient had micro haematuria what further investigations would you do
Autoantibodies +/- renal biopsy, (polyarteritis) US (renal Ca)
If patient had TB contact what further investigations would you do
Sputum smear, bone marrow, Mantoux
