Pyrexia of Unknown Origin

Question 1

What is the diagnostic criteria for PUO?

Answer 1

Fever recorded on multiple occasions with no diagnosis after

• 3 days of hospital investigations
• or one week of outpatient investigations/3 visits

Question 2

Major disease categories which can present with a PUO?

Answer 2

Infection
Malignancy
Inflammatory

Nosocomial
Neutropenic
HIV-Associated - fever in those known to have HIV: TB, mycobacterium avium

Question 3

Important aspects to cover in history?

Answer 3

Travel
Occupation
Hobbies
FH/PMH/DH
Pattern of Fever

Question 4

What parts of the body should you pay special attention to when examining?

Answer 4

Skin
Eyes
Oral cavity
Nails
Lymph nodes

Question 5

Preliminary Investigations?

Answer 5

CXR
Urinalysis and urine microscopy
FBC/WCC
CRP, ESR
Blood cultures at times of fever
Urea, creatinine, electrolytes, LFTs

Question 6

What more specific imaging/investigations may be done if certain symptoms/risk factors are present?

Answer 6

Tropical travel - blood for malarial parasites/dengue/HIV
New murmur - ECHO (trans-oesophageal sometimes required)
Headaches - Temporal artery biopsy
Microhaematuria - USS (renal cancer), autoantibodies, renal biopsy
TB - sputum, bone marrow, mantoux
Drug misuse - BBV search

Question 7

When is a ‘therapeutic trial’ used?

Answer 7

Suspected mycobacterial infection (anti-TB therapy)

Suspected vasculitis or connective tissue disorder (Steroids)