Pyrexia of unknown origin Flashcards
What is a normal temperature?
37’C
What is fever?
Elevation of body temp above normal (37)
How much can temperature vary normally?
0.8’C
What is SIRS?
Systemic inflammatory response syndrome (SIRS)
What are pyrogens?
Substances which cause fever
What are the two types of pyrogens?
Endogenous
Exogenous
What is an example of endogenous pyrogens?
Cytokines
What is an example of exogenous pyrogens?
Endotoxins from G-ve bacteria
What is the old definition of pyrexia?
Temp >38.8
Multiple occasions
At least 3 wks
One wk hospital evaluation
What is the modern definition of pyrexia?
3 outpatient visits OR
3 days in hospital OR
1 week outpatient investigation
What is nosocomial PUO?
Develops in hospital, undiagnosed after 3 days
What is neutropenic PUO?
Undiagnosed fever in patient with neutrophils <500/mm^3
What is HIV-associated PUO?
Fever in patient with HIV infection, present and undiagnosed >3days inpatient, >4wks outpatient
What are causes of classical PUO?
Infection Malignancy Inflammatory Other No diagnosis
What bacteria is the most common cause of PUO?
Mycobacterium
What are initial investigations for PUO?
CXR Urinalysis and urine microscopy FBC, WCC CRP, ESR Blood cultures Urea, creatinine, electrolytes, LFTs
What investigations would be indicated for tropical travel?
Blood for malarial parasites, dengue, HIV
Bone marrow for leishmaniasis
(less likely >21 days return)
What investigations would be indicated for new murmur?
ECHO
TOE
What investigations would be indicated for headaches?
Temporal artery biopsy (TA)
What investigations would be indicated for micro-haematuria?
Auto-antibodies +/- renal biopsy (polyarteritis)
US (renal Ca)
What investigations would be indicated for TB contact?
Sputum smear
Bone marrow
Mantoux
What investigations would be indicated for drug misuse?
Screen for blood-borne viruses
What are invasive investigations for PUO?
Tissue for culture and histology
Bone marrow and liver biopsy
Diagnostic laparotomy
When would a therapeutic trial happen in PUO?
Suspected mycobacterial infection
What is the response of temporal arteritis to steroids?
Dramatic - within 48hrs
What is a fabricated fever?
Real but self-induced
Self-injection
What is the treatment for PUO?
Young - often spontaenous
NSAIDs/steroids