Fever and PUO Flashcards by Brooke Ward

Define PUO?

Prolonged illness (2-3 weeks)
Fever (>38.3) on several occasions
No diagnosis after intelligent investigations

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What is the normal oral temperature range?

35.8-37.8

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Describe the diurnal variation in body temperature?

Lowest in morning
Highest in afternoon
Varies by 0.5-1

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Where is body temperature regulated?

Anterior hypothalamus

Temperature sensitive neurons

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Define fever?

Early morning oral temp > 37.2

Oral temp > 37.8 at any time

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Describe how measurement of temperature may vary?

Oral: < core body temp by 0.5
Axillary: < core body temp by 1
Ear probe closer to core temp

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What is the optimum temperature for fighting an infection?

39.5

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Describe rigor?

Feeling of intense cold
Uncontrollable shivering
Pallor
Pilo-erection
Exhaustion afterwards with high fever (>39)

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What is the most common cause of fever of short duration?

Infection

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Which life-threatening conditions associated with fever of short duration must be detected and treated immediately?

Meningococcaemia
Falciparum malaria
Bacterial meningitis
Post splenectomy sepsis
TSS
Necrotising soft tissue infections
Head and neck space infections
Febrile neutropaenia
Acute staph aureus endocarditis
Severe pneumonia

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Describe the symptoms of TSS?

Hypotension
Fever
Rash

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Describe the symptoms of necrotising soft tissue infections?

Severe local pains
Fever
Chills

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Which patients presenting with fever are most at risk for a serious illness?

Recent OS travel
Asplenic
Neutropaenic
Elderly
Diabetic
IVDU

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Which signs, along with fever, indicate a serious illness in a patient?

Shock
Impaired conscious state
Cyanosis
Tachypnoea

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What symptoms that present with acute fever are warning bells?

Rapid onset/evolution
Rigors
Severe muscle pain
Impaired conscious state
Vomiting
Severe headache
Rash
Jaundice

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Why is vomiting associated with fever an alarm bell?

Vomiting can be associated with raised ICP

Can be caused by toxins

Why is severe headache associated with fever an alarm bell?

Meningitis

Why is jaundice associated with fever an alarm bell?

Can be a marker of sever illness, especially sepsis

Describe the management of a patient that presents with fever?

Investigations: FBE, CRP, renal function, liver function, blood and urine cultures, CXR
Empirical IV antibiotics (if bacterial infection likely)
Admit or prolonged stay in ED

Describe how the WCC and CRP levels may change through the course of an infection?

takes time for immune system to respond > may take up to 12 hours to see elevation

What should be considered in a patient with prolonged fever?

Occupation/animal exposure 
Country of origin 
Travel - local or OS for past 2 years
Contact with toddlers
Risk for SBE
New sexual contacts
New medications

Why is country of origin important in prolonged infection?

Possibility of TB

Why is any travel in the past two years significant for a patient presenting with prolonged fever?

Vivax malaria has prolonged liver phase

What is the most common cause of prolonged fever in young couples with toddlers?

Acute CMV

Children are fine when infected, but transferred to adults > symptomatic 2-3 weeks later

Describe the investigations that should be carried out on a patient with prolonged fever?

``` FBE ESR CRP LFT CXR Serology for unusual infections Blood and urine cultures ```

What may show up on an FBE of a patient with prolonged fever?

Atypical lymphocytosis: infectious mononucleosis (EBV< CMV, HIV) Neutrophilia: bacterial/inflammatory process EXCLUDE MALARIA

What would a high ESR indicate in a patient with prolonged fever?

Non-specific | High with prolonged bacterial infection or vasculitis

What would a very high CRP in a patient with prolonged fever suggest?

Bacterial infection/inflammation

Why is a CXR performed in a patient with prolonged fever?

Atypical pneumonia

Why aren't empirical antibiotics given to a patient with prolonged fever?

Side effects of antibiotic may confuse clinical picture

When would empirical antibiotics be given to a patient with prolonged fever?

If Q fever or atypical pneumonia were highly likely

Describe the clinical approach to diagnosing PUO?

1) Onset and duration (when were they last well?) 2) Seek localising symtpoms 3) Establish severity (weight loss? night sweats?) 4) Is there really a fever? 5) Obtain information and review all results 6) Past Hx, family Hx, medications 7) Country of origin 8) Travel history (last 10 years) 9) Occupation, animal exposure 10) Sexual history and IVDU

What are the differential diagnoses for PUO?

Infections Connective tissue disorders Malignancies Other: drug fever, factitious fever, benign pyrexia

Which infections could cause PUO?

``` Subacute bacterial endocarditis (SBE) TB Intra-abdominal abscess HIV related opportunistic infection Other: EBV, CMV, brucella, Q fever, malaria ```

Which connective tissue diseases could cause PUO?

``` Polymyalgia rheumatica Giant cell arteritis Vasculitis Adult Still's disease SLE Acute thyroiditis Granulomatous diseases: sarcoidosis, Crohn's ```

Describe the physical examination of a patient with PUO?

``` Eyes Temporal arteries Teeth and gums Thyroid gland tenderness Heart murmur/rub Lymph nodes Hepatosplenomegaly Kidney mass Rash/arthritis ```

Describe the investigations for a patient with PUO?

Repeat and review basic bloods and cultures MSU ANA, RF, ANCA Iron studies LDH, beta 2 microglobulin HIV serology Consider serology for EBV, CMV, brucellosis, Q fever, psittacois, bartonella, syphilis Consider TB Imaging: CXR, CT abdo/pelvis, PET scanning Tissue sample if you still don't have a diagnosis