Pyrexia of Unknown Origin Flashcards
Diagnostic criteria of PUO.
Pyrexia > 3 weeks with no identified cause after evaluation in hospital for 3d or 3 or more out-patient visits.
Nosocomial PUO - Patient hospitalised for > 48h with no infection at admission
Immunodeficient PUO - Pyrexia in patient with < 500 neutrophils/microlitre
HIV PUO - Pyrexia in HIV infection lasting 3d as an in-patient or > 4 weeks as an outpatient.
Classical definition of PUO.
Temp > 38 degrees on multiple occasions
Fever > 3 weeks of duration
No diagnosis despite > 1 week’s worth of inpatient.
History of PUO
Chronology of symptoms
Travel
Diet
Animal contact
Changes in medication
Recreational drug use
Obstetric/sexual history
Family History
Occupation
Vaccination history
Examination of PUO.
Mouth
Genitals
Skin
Thyroid
Lymph nodes
Eyes including retina
Temporal arteries
Stigmata of endocarditis
Evidence of weight loss
Joint abnormalities
Investigations of PUO.
Bloods
Micro/virology/immunology
Imaging
Biopsies
Bloods done in PUO.
FBC, U&Es, LFTs, Bone profile, CRP, Clotting, TFT, Multiple sets of blood cultures, LDH, Ferritin, B12, folate, Immunoglobulins, autoimmune screen such as RF, ANA, dsDNA, pANCA, cANCA, C3, C4
Micro/virology done in PUO.
HIV
Hep B and C
Syphilis
MSU
Sputum cultures
Malaria films
Atypical pneumonia screen
Viral swabs
CMV+EBV serology
Brucella serology
Coxiella serology
ASO titre
Fungal serology/PCR
Imaging done in PUO.
CXR
CT thorax/abdo/pelvis
Transthoracic echo
MR head
MR spine
Radiolabelled white cell scans
PET scan
Biopsies done in PUO
MC+S
TB culture
HIstology on all samples
Bone marrow, lymph nodes, abscesses, liver
Causes of PUO.
Infective such as TB, abscess, infective endocarditis, brucellosis.
Autoimmune/connective tissue such as adult onset Still’s disease, temporal arteritis, granulomatous polyangiitis, polymyalgia rheumatica.
Neoplastic such as leukaemias, lymphomas, renal cell carcinoma, HCC.
Others such as drugs, thromboembolism, hyperthyroidism, adrenal insufficiency.
Management of PUO.
Aim to establish a diagnosis instead of treating blindly.
Do not start empirical antibiotics/steroids/antifungals without speaking to a registrar or consultant. These can be detrimental if initiated.
Ask rheumatology and haematology to see PUO depending on presentation.
Try and stay up to date on what tests have been done.
Stable patients can be managaed as outpatients following a period of observation in hospital.
In patients with no diagnosis despite prolonged investigation, the prognosis tends to still be good.
Infectious causes of PUO
Extrapulmonary TB
Abscesses
Q fever
Endocarditis
Osteomyelitis
Infected thrombosis
Malaria
Brucellosis
Malignant causes of PUO
Haematological malignancies like;
Lymphoma
Leukaemia
Multiple Myeloma
Solid Tumours;
Pancreatic Adenocarcinoma
HCC
Renal cell carcinoma
Non-infectious causes of PUO
SLE
RA
Temporal arteritis (and other vasculites)
Sarcoidosis
Adult-onset Still’s disease
Familial mediterranean fever
Miscellaneous causes of PUO
Drug fever
Factitious fever
Hypothalamic dysfunction
Idiopathic (most common cause worldwide)
