Pyrexia of Unknown Origin (PUO)

Question 1

What is normal body temperature?

Answer 1

37 degrees

Question 2

When is someone considered to be having a fever?

Answer 2

If temperature above 38

Question 3

Pyrogens?

Answer 3

Substances which cause fever

Question 4

Give an example of a endogenous pyrogen.

Answer 4

Cytokines

Question 5

Give an example of a exogenous pyrogen.

Answer 5

Endotoxins from gram negative bacteria

Question 6

Pyrexia?

Answer 6

Fever, raised temperature

Question 7

What are some of the criteria for pyrexia of unknown origin?

Answer 7

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

Question 8

What is meant by nosocomial pyrexia of unknown origin?

Answer 8

PUO which develops in hospital and is undiagnosed within three days

Question 9

What is meant by neutropenic pyrexia of unknown origin?

Answer 9

Undiagnosed fever in a patient with neutrophils <500/mm3

Question 10

What is meant by HIV-associated pyrexia of unknown origin?

Answer 10

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

Question 11

What are the four main areas of causes of PUO?

Answer 11

Infection
Neoplasm
Inflammatory
Miscellaneous

Question 12

In a patient with PUO, what is important to do initially?

Answer 12

Thorough history and examination

Question 13

What travel related condition can present with PUO?

Answer 13

Malaria as can have benign relapsing malaria even 5 or 6 years after leaving an endemic area

Question 14

What should a thorough examination in a patient with PUO include?

Answer 14

Looking at skin, eyes, oral cavity, nails and lymph nodes

Question 15

List some potential investigations to consider in someone with PUO.

Answer 15

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

Question 16

If a patient has PUO and a history of tropical travel, which investigation may get carried out?

Answer 16

Bloods for malarial parasites
Dengue (a mosquito-borne tropical disese)
HIV
Bone marrow

->less likely if >21 days since return

Question 17

If a patient has PUO and a new murmur, which investigation may get carried out?

Answer 17

ECHO

Question 18

If a patient has PUO and headaches, which investigation may get carried out?

Answer 18

Temporal artery biopsy

->may be giant cell arteritis

Question 19

If a patient has PUO and microhaematuria which investigation may get carried out?

Answer 19

Auto-antibodies +/- renal biopsy, ultrasound

Question 20

If a patient has PUO and TB contact in their history, which investigation may get carried out?

Answer 20

Sputum smear
Bone marrow
Mantoux test (test which sees if patient has been exposed to TB)

Question 21

If a patient has PUO and a history of drug misuse which investigation may get carried out?

Answer 21

Screen for blood borne viruses

Question 22

What is the treatment for patients with PUO if a diagnosis cannot be made?

Answer 22

Therapeutic trial based on clinical suspicion

e.g. if history raises suspicion of TB, they would be given antituberculotic therapy

Question 23

What is the risk of offering patients with PUO a trial of treatment?

Answer 23

May mask new signs which could help with making a diagnosis
Patient may develop toxicity

Question 24

At what stage would the therapeutic trial of treatment be stopped?

Answer 24

If there was no response, certainly after two weeks of treatment

Question 25

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?

Answer 25

Steroids

Question 26

What is meant by a fabricated fever?

Answer 26

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

Question 27

What should be done in patients with fabricated fevers?

Answer 27

Seek psychiatric help...do not confront directly

Question 28

What is the prognosis like for young patients with PUO?

Answer 28

Tend to recover spontaneously

Question 29

What is the prognosis like for older patients with PUO?

Answer 29

Tend to not improve and typically is due to a hard to diagnose malignancy