Pyrexia of unknown origin Flashcards
What is fever?
Elevation of body temperature above normal
What is normal variation in body temperature?
Around 0.8
What is a pyrogen?
Substance which causes fever
How do pyrogens raise temperature?
Act at hypothalamic thermoregulatory centre to cause reduced heat loss
What exogenous substances are pyrogens?
Endotoxins from gram negative bacteria
How is pyrexia of unknown origin defined?
Pyrexia with no diagnosis after 3 outpatient visits, 3 days in hospital, or one week of outpatient investigation
What is nosocomial pyrexia of unknown origin?
Pyrexia develops in hospital, undiagnosed after 3 days
What is neutropenic pyrexia of unknown origin?
Undiagnosed fever in patient with neutrophils <500
What is HIV associated pyrexia of unknown origin?
Fever in a patient with HIV infection, present and undiagnosed for more than 3 days in hospital or 4 weeks in outpatient
What should be asked about in the history?
Travel Occupation Hobbies Family history Past medical and surgical history Drug history Pattern of fever
What should be examined?
Skin Eyes Oral cavity Nails Lymph nodes
What are initial investigations for pyrexia of unknown origins?
CXR Urinalysis Urine microscopy FBC and differential white cell count CRP ESR Blood cultures taken at times of fevers Urea Creatinine Electrolytes LFTs
What additional investigations should be done in somebody who has travelled tropically recently?
Blood for malarial parasites
Dengue
HIV
Bone marrow for leishmaniasis
What additional investigations should be done in somebody with a new heart murmur?
ECHO
What additional investigation should be done in someone with headaches?
Temporal artery biopsy
