Pyrexia of Unknown Origin (PUO) Flashcards
What is normal body temperature?
37 degrees
When is someone considered to be having a fever?
If temperature above 38
Pyrogens?
Substances which cause fever
Give an example of a endogenous pyrogen.
Cytokines
Give an example of a exogenous pyrogen.
Endotoxins from gram negative bacteria
Pyrexia?
Fever, raised temperature
What are some of the criteria for pyrexia of unknown origin?
Prolonged fever for
3 outpatient visits
or
3 days in hospital
or
One week of outpatient investigations
all in which a diagnosis cannot be made
What is meant by nosocomial pyrexia of unknown origin?
PUO which develops in hospital and is undiagnosed within three days
What is meant by neutropenic pyrexia of unknown origin?
Undiagnosed fever in a patient with neutrophils <500/mm3
What is meant by HIV-associated pyrexia of unknown origin?
Fever in a patient with HIV which has been present and undiagnosed for more than three days as in inpatient or four week as an outpatient
What are the four main areas of causes of PUO?
Infection
Neoplasm
Inflammatory
Miscellaneous
In a patient with PUO, what is important to do initially?
Thorough history and examination
What travel related condition can present with PUO?
Malaria as can have benign relapsing malaria even 5 or 6 years after leaving an endemic area
What should a thorough examination in a patient with PUO include?
Looking at skin, eyes, oral cavity, nails and lymph nodes
List some potential investigations to consider in someone with PUO.
CXR
Urinalysis
FBC and WCC
C-Reactive Protein and ECR
Blood cultures
Urea
Creatinine
Electrolytes
LFT’s
->basically, all the simple stuff as often these can get missed
If a patient has PUO and a history of tropical travel, which investigation may get carried out?
Bloods for malarial parasites
Dengue (a mosquito-borne tropical disese)
HIV
Bone marrow
->less likely if >21 days since return
If a patient has PUO and a new murmur, which investigation may get carried out?
ECHO
If a patient has PUO and headaches, which investigation may get carried out?
Temporal artery biopsy
->may be giant cell arteritis
If a patient has PUO and microhaematuria which investigation may get carried out?
Auto-antibodies +/- renal biopsy, ultrasound
If a patient has PUO and TB contact in their history, which investigation may get carried out?
Sputum smear
Bone marrow
Mantoux test (test which sees if patient has been exposed to TB)
If a patient has PUO and a history of drug misuse which investigation may get carried out?
Screen for blood borne viruses
What is the treatment for patients with PUO if a diagnosis cannot be made?
Therapeutic trial based on clinical suspicion
e.g. if history raises suspicion of TB, they would be given antituberculotic therapy
What is the risk of offering patients with PUO a trial of treatment?
May mask new signs which could help with making a diagnosis
Patient may develop toxicity
At what stage would the therapeutic trial of treatment be stopped?
If there was no response, certainly after two weeks of treatment
Some issues, like vasculitis or connective tissue disorders do not have a diagnostic test ad the only way to treat is by giving a therapeutic trial of which kind of drug?
Steroids
What is meant by a fabricated fever?
A fever which is real but self-induced
->e.g. someone with healthcare knowledge may inject themselves with soap or contaminated debris to precipitate a fever
What should be done in patients with fabricated fevers?
Seek psychiatric help…do not confront directly
What is the prognosis like for young patients with PUO?
Tend to recover spontaneously
What is the prognosis like for older patients with PUO?
Tend to not improve and typically is due to a hard to diagnose malignancy
