Pyrexia of unknown origin

Keywords: PUO

Causes

Appropriate Tests

PUO is defined as undiagnosed fever of more than 3 weeks duration.

Careful and repeated clinical history and examination; Full blood count, Blood film, White cell count differential; C-Reactive protein; Bilirubin, Alkaline phosphatase, Aspartate aminotransferase, Alanine aminotransferase, Gamma glutamyltransferase, Lactate dehydrogenase.

Note whether and where patient has been travelling (see Guideline on Pathology testing in the Emergency department: Appendix 2.).

Bacterial infection, especially

Blood culture (repeated); MCS urine; Faeces MCS and antigen.

Endocarditis

See Endocarditis (infective)

Abscess, especially

  • Intra-abdominal

 

Ascending cholangitis

See Cholestasis

Urinary tract infection

 

Osteomyelitis

 

Typhoid fever

 

Tuberculosis

Urine for mycobacteria testing; collect early morning specimens (three).

Brucellosis

 

Fungal infection

 

Cryptococcal infection

Cryptococcal Ag, Cerebrospinal fluid examination, if appropriate.

Protozoal infection

 

Malaria

Malaria, Parasites blood - repeated thin and thick blood films, if indicated.

Toxoplasmosis

 

Viral infection

 

Cytomegalovirus infection

 

HIV infection

 

Drug fever

 

Malignancy, especially

Fine needle aspiration biopsy, Lesion biopsy; as appropriate. Tumour markers are unreliable as a screening test for occult malignancy.

Renal cell carcinoma

 

Hepatocellular carcinoma

 

Disseminated carcinoma

 

Hodgkin lymphoma

 

Lymphoma (non-Hodgkin)

 

Atrial myxoma

 

Other

 

Connective tissue diseases

 

Vasculitis

 

Granulomatous hepatitis

See Hepatitis - Granulomatous

Sarcoidosis

 

Crohn's disease

 

Familial Mediterranean fever

Clinical diagnosis.

C-Reactive protein (intermittent elevation); biopsy of appropriate tissue only if clinical features suggest amyloidosis.

Occult haematoma, especially

  • Retroperitoneal haematoma

 

Factitious fever