Pyrexia of Unknown Origin Flashcards

1
Q

Describe fever

A

Elevation of body temp above normal (37)

Variation of up to 0.8 daily; low in early morning, high in early evening

Part of systemic inflammatory response syndrome (SIRS)

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2
Q

Describe fever

A

Elevation of body temp above normal (37)

Variation of up to 0.8 daily; low in early morning, high in early evening

Part of systemic inflammatory response syndrome (SIRS)

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3
Q

Describe pyrogens

A

Substances which cause fever

  • endogenous e.g. cytokines
  • exogenous e.g. endotoxins from G-ve bacteria
  • act at hypothalamic thermoregulatory centre to cause reduced heat loss and hence fever
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4
Q

Describe pyrexia of unknown origin

A

Petersdorf and Beeson (1961)

  • temp > 38.3
  • recorded on multiple occasions
  • presented for at least three weeks
  • defied diagnosis after one week of hospital evaluation

Modern definition is broader

  • 3 outpatient visits
  • 3 days in hospital
  • or one week of outpatient investigation
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5
Q

Different types of PUO

A

Classical PUO

Nosocomial PUO; develops in hospital, undiagnosed after 3 days

Neutropenic PUO; undiagnosed fever in patient with neutrophils <500/mm3

HIV-associated PUO; fever in a patient with HIV infection - present and undiagnosed for more than three days in an outpatient or four weeks in an outpatient

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6
Q

PUO history and examination

A

Take your time

Travel, occupation, hobbies, FH, PM and Surgical history, drug history, pattern of fever

Examine skin, eyes, oral cavity, nails and lymph nodes

Repeated examination often worthwhile

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7
Q

PUO initial investigations

A
  • CXR
  • Urinalysis and microscopy
  • FBC and differential WCC
  • CRP and ESR
  • Blood cultures taken at times of fevers
  • Urea, creatinine, electrolytes, LFTs
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8
Q

PUO tropical travel investigation

A

Blood for malarial parasites, dengue, HIV, bone marrow for leishmaniasis

Less likely if >21days since return

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9
Q

PUO new murmur investigations

A

Echocardiography

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10
Q

PUO headache investigations

A

Temporal artery biopsy

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11
Q

PUO micro hameaturia

A

Auto-antibodies +/- renal biopsy

US

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12
Q

PUO TB contact investigations

A

Sputum smear

Bone marrow

Mantoux

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13
Q

PUO drug misuse investigations

A

Screen for blood-borne viruses

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14
Q

PUO imaging techniques

A

More valuable if they have direction

cannot always differentiate between infection and inflam

Anatomical changes may not develop in immunocompromised

CT-PET

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15
Q

Describe pyrogens

A

Substances which cause fever

  • endogenous e.g. cytokines
  • exogenous e.g. endotoxins from G-ve bacteria
  • act at hypothalamic thermoregulatory centre to cause reduced heat loss and hence fever
How well did you know this?
1
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2
3
4
5
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16
Q

Describe pyrexia of unknown origin

A

Petersdorf and Beeson (1961)

  • temp > 38.3
  • recorded on multiple occasions
  • presented for at least three weeks
  • defied diagnosis after one week of hospital evaluation

Modern definition is broader

  • 3 outpatient visits
  • 3 days in hospital
  • or one week of outpatient investigation
17
Q

Different types of PUO

A

Classical PUO

Nosocomial PUO; develops in hospital, undiagnosed after 3 days

Neutropenic PUO; undiagnosed fever in patient with neutrophils <500/mm3

HIV-associated PUO; fever in a patient with HIV infection - present and undiagnosed for more than three days in an outpatient or four weeks in an outpatient

18
Q

PUO history and examination

A

Take your time

Travel, occupation, hobbies, FH, PM and Surgical history, drug history, pattern of fever

Examine skin, eyes, oral cavity, nails and lymph nodes

Repeated examination often worthwhile

19
Q

PUO initial investigations

A
  • CXR
  • Urinalysis and microscopy
  • FBC and differential WCC
  • CRP and ESR
  • Blood cultures taken at times of fevers
  • Urea, creatinine, electrolytes, LFTs
20
Q

PUO tropical travel investigation

A

Blood for malarial parasites, dengue, HIV, bone marrow for leishmaniasis

Less likely if >21days since return

21
Q

PUO new murmur investigations

A

Echocardiography

22
Q

PUO headache investigations

A

Temporal artery biopsy

23
Q

PUO micro hameaturia

A

Auto-antibodies +/- renal biopsy

US

24
Q

PUO TB contact investigations

A

Sputum smear

Bone marrow

Mantoux

25
Q

PUO drug misuse investigations

A

Screen for blood-borne viruses

26
Q

PUO imaging techniques

A

More valuable if they have direction

cannot always differentiate between infection and inflam

Anatomical changes may not develop in immunocompromised

CT-PET

27
Q

PUO Invasive investigations

A

Obtain tissue for culture and histology

Bone marrow and liver often examined as part of blind investigation; malignancy, TB, lymphoma

Diagnostic laparotomy
- rarely necessary

28
Q

Describe fabricated fever

A

Fever real but self-induced

Self injection common

Microbiology may be strongest clue

Patient often continues despite being very sick

Psychiatric expertise should be sought rather than direct confrontation

29
Q

Outcome of PUO

A

Spontaneous resolution more common in young than old

Some patients with no diagnosis respond to NSAIDs or steroids

Regular re-appraisal required; answer may not become apparent for many months