Pyrexia of Unknown Origin Flashcards
Define Fever
Elevation of body temperature above normal (37). Part of the systemic inflammatory response syndrome.
What are pyrogens
Substances which cause fever.
What are endogenous pyrogens
Cytokines
What are exogenous pyrogens
Endotoxins from gram - bacteria
How do pyrogens work
Act at the hypothalamic thermoregulatory centre to cause reduced heat loss and hence fever
Define Pyrexia of Unknown Origin
No diagnosis after 3 outpatient visits, or 3 days in hospital or one week of outpatient investigation.
What is nosocomial pyrexial of unknown origin
This develops in hospital and is 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 three days in an inpatient or four weeks in an outpatient
List the possible causes of classical PUO
Infection, neoplasm, collagen, miscellaneous or undiagnose
State the main causes of HIV related PUO
Mycobacteria tuberculosis, mycobacteria avium or more than one causative agent
State the initial investigations conducted into PUO
CXR, urinalysis, FBC and differential WCC, C-reactive protein and ESR, blood cultures, urea, creatinne, electrolytes and liver function tests
State the imaging techniques used in PUO
MRI, PETCT, CT, Radio-isotope scan, ultrasound scan
State the invasive investigations that can be used in PUO
Tissue for culture and histology, bone marrow and liver biopsy, diagnostic laparotomy
State the treatment of PUO
Therapeutic trial - mycobacterial infection try anti-TB therapy, suspected vasculitis try steroids.
