Pyrexia of Unknown origin Flashcards
What is a PUO?
A PUO, or pyrexia of unknown origin is a fever/high temperature in someone, whihc after significant and relevant tests, has no clear underlying cause
Name some examples of each of the following cause of infections that can cause pyrexia
- Viral
- Parasites
- Fungal
- Bacterial
- Viral - CMV/EBV, HIV, Hepatitis
- Parasites - Malaria, amoebic liver abcess, toxoplasmosis
- Fungal - Cryptococcosis, histoplasmosis
- Bacterial - Mycobacteria, TB, NTM, enteric fever e.g. Salmonella typhi
Describe when the following is present in serology for someone with EBV
- VCA IgM
- VCA IgG
- EBNA-1 IgG
- EBV DNA
- Heterophile test
- IgM - positive at symptom onset and remains for 2-4 weeks
- IgG - positive at symptom onset and remains for life
- EBNA-1 IgG - positive at 3-4 weeks after symptoms and remains for life
- EBV DNA - rapidly cleared usually before symptoms if immunocompetent
- Heterophile test - not specific and poorly sensitive, not recommended
What can be useful to do in people with PUO?
PET/CT
What are some of the diagnostic pitfalls of the following:
- Ferritin
- Bone marrow aspirate
- Interferon gamma release assay (IGRA) (TB)
- Ferritin - very high ferritin classically associated with adult onset stills disease and macrophage activation syndrome. However, significant overlap with some infective causes
- Bone marrow aspirate - Histopathological examination helpful in suspected haematological malignancies. However, not helpful in HIV patients
- IGRA (TB) - limited sensitivity and specificity for active TB - looks for latent TB
What is Dukes criteria?
Dukes criteria for endocarditis - need 2 major or 1 major +3 minor criteria
Major criteria:
- Persistent bacteraemia
- echocardiogram - vegetation
- positive serology for Bartonella, coxiella or brucella
Minor:
- Predispostition - murmur, IVDU
- Inflammatory markers - fever, high CRP
- Immune complexes: splinters, RBCs in urine
- Embolic phenomena: Janeway lesions, CVA
- Atypical echo
- I positive BC
Describe the following about Giant cell arteritis:
- Age usually affected
- Symptoms
- Investigation findings
- Gold standard
- complications
- Over 50’s
- Headache, jaw claudication, 50% will have vision change on presentation
- ESR >45, CRP high
- Gold standard investigation is temporal biopsy
- Needs to be treated immediately, as a high risk of sight impairment/stroke
What is Adult onset stills and Macrophage activation syndrome?
- Salmon pink rash
- Can be mistaken for drug eruption/rash
- Ferritin often VERY high in adult onset stills leading to MAS
What are the major and minor criteria for adult onset stills and Macrophage activation syndrome (MAS)?
Major:
- Temperature >39 for more than 1 week
- Leukocytosis
- Typical salmon pink rash
- Arthalgias for more than 2 weeks
Minor:
- Sore throat
- lymphadenopathy
- splenomegaly/hepatomegaly
- abnormal liver function studies
- negative tests for ANA and RhF
What are some malignant causes of PUO?
- Lymphoma -especially Non-Hodgkin’s - raised LDH, weight loss
- Leukaemia - bone marrow biopsy needed
- Renal cell carcinoma - 20% of cases present with fever, haematuria
- Hepatocellular carcinoma or other tumors metastatic to the liver
As well as infectious and malignant causes, what else can cause PUO?
Drugs:
- Beta lactams antibiotics, hyptensive drugs can both cause a raised temperature
- adverse drug reactions
Which of the following details in this ladies history would go against a diagnosis of GCA?
A. ESR = 45
B. No scalp tenderness on palpation
C. Patient is 47 years old
D. Has got perfect visual acuity
E. Ferritin <500
C. Patient is 47 years old
Which of these investiagtions should be performed as part of a patients initial primary work up of an undifferentiated pyrexia?
A. Cryoglobulins
B. dsDNA
C. CT chest/abdo/pelvis
D. HIV test
E. Brucella serology
D. HIV test
Which would be the most useful test in confirming acute EBV infection 2 weeks after possible exposure in an immunocompetent patient?
A. EBV PCR
B. EBV blood cultures
C. EBV IgG
D. EBV IgM
E. Heterophile antibody test (Monospot)
D. EBV IgM
Which of the following malignancies is least likely to be associated with fevers?
A. Lymphoma
B. Renal cell carcinoma
C. Leukemia
D. Hepatocellular carcinoma
E. Adenocarcinoma of the lung
E. Adenocarcinoma of the lung
