Fever

Question 1

Describe the effect of body site on temperature

Answer 1

Pulmonary artery > tympanic membrane > oral

Question 2

What is the gold standard for measuring core body temperature?

Answer 2

Pulmonary artery temperature

Question 3

When should axillary temperature be used?

Answer 3

Unreliable in adults and should NOT be used

Question 4

What factors may impact oral temperature?

Answer 4

Site within mouth

Whether mouth previously open or closed

Question 5

List 8 signs of a severe infection

Answer 5

RR >24

HR >120

SBP 120

T 39C

SpO2 under 95%

Hypothermia (common in elderly pts with severe infection) less than 35.5

Altered conscious state

Pallor, mottled skin, cool peripheries

Question 6

How many blood cultures should be taken and where from? How much blood in each bottle?

Answer 6

2 sets from 2 sites

10mL of blood from adults

Question 7

Define PUO

Answer 7

Illness >3 weeks

Fever >38.3C

No diagnosis after intelligent assessment

Question 8

What is the most common cause of PUO?

Answer 8

Infection

Question 9

When is temperature lowest throughout the day? When is it highest?

Answer 9

Early morning

Highest around late afternoon/evening

Question 10

What are the key questions to ask when assessing a patient with fever?

Answer 10

Duration, and rate of evolution of Sx

Localising Sx (detail essential)

Immunosuppression (including DM and its control)

Recent hospitalisation

Recent illness of contacts

Any foreign bodies or prostheses

SHx: occupation, recreation, hobbies (including animal contact)

Rx (esp new)

Recent travel (detail essential: need to know geographical Hx, setting i.e. if rural or urban, type of accommodation, time of onset and duration of Sx, activities undertaken, food Hx, sexual activity, prior vaccinations, malaria prophylaxis, fresh or salt water exposure)

Injecting drug use

Sexual Hx

Question 11

What constitutes a temperature?

Answer 11

>37.1 in early morning

>37.7 in late afternoon/evening

Question 12

List 5 warning bells on Hx in patients with fever

Answer 12

Pt presents within 1st 24 hrs of illness

Pt presents for 2nd time within a short period

Severe muscle pain

Severe localised pain

Repeated vomiting but no diarrhoea

NB The elderly frequently have non-localising Sx despite serious bacterial infection

Question 13

What are the key findings to look for O/E in a patient with fever?

Answer 13

Abnormal vital signs (note not all pts with significant infection have fever)

Signs related to local Sx

Areas commonly missed in cursory examinations: entire skin (for petechiae, rashes), nails (for splinter haemorrhages), conjunctivae (for petechiae), soft heart murmurs, retinae (for haemorrhages and exudates), tenderness in loins/spine/temporal arteries/thyroid/teeth (+ look for caries)/prostate

Should always perform urinalysis/FWT!

Repeated examinations are often necessary if source of fever is unclear

Question 14

List 6 warning bells in examination of patients with fever

Answer 14

Vitals: lower BP than usual for that pt (or septic frank shock), tachypnoea

Patient now incapicitated (e.g. unable to walk or stand)

Altered conscious state, behavioural change

Petechiae

Jaundice (remember that fever has subsided in most patients with viral hepatitis by the time they become jaundiced), but an exception to this “warning sign” is the patient with Gilbert’s syndrome (can be normal for them to become mildly jaundiced with minor infections)

Question 15

6 non-specific Ix in patient with fever (may not all be necessary, depending on initial clinical assessment)

Answer 15

FBE

UEC

LFTs

BGL

Blood gases (if patient shocked, in possible acidosis or respiratory failure)

CRP

Question 16

9 more specific Ix in patient with fever (dependent on initiSaveal clinical assessment)

Answer 16

Urinalysis/FWT (should be routine part of physical exam!)

MSU for MCS

CXR

Blood cultures (not necessary in all patients with fever)

If relevant, appropriate tests related to travel (e.g. malaria ICT, thick and thin films, stool culture, serology e.g. hepatitis, amoebic, arbovirus, other)

CT abdo/chest/pelvis

Biopsy of relevant tissue (e.g. LN, temporal artery) for histology and appropriate culture

Serology (e.g. HAV, HBV, HCV or if early infection may need HCV PCR, EBV, CMV, HIV, other)

Haemolytic screen (FBE, film, RCC, direct and indirect Coombs, LDH, haptoglobin)

Question 17

What key Mx decisions must be considered in the initial treatment of the patient with fever?

Answer 17

Empiral Abx?

ICU support?

Is an urgent intervention to drain a septic focus or prosthesis required?

Question 18

List 14 syndromes presenting with fever which may require urgent treatment

Answer 18

Septicaemic shock

Suspected bacterial meningitis

Suspected meningococcaemia

Necrotising soft tissue infections

Falciparum malaria

Fever in a splenectomised pt

Focal paraspinal or intracranial infections

Severe pneumonia

Febrile neutropenia

Suspected staphylococcal septicaemia

Acute IE

Deep infections of head and neck

TSS

Neuroleptic malignant syndrome

Question 19

5 common Dx mistakes made in Mx of patients with fever

Answer 19

Failing to collect 2 sets of blood cultures before commencing Abx in pts in whom a source of infection is not clearly apparent

Treating adults with spontaneous septic arthritis without first collecting blood cultures

Making a Dx of viral meningitis before CSF PCR is available or the pt has recovered; viruses are only one cause for an aseptic meningitis syndrome

Not considering meningitis unless the pt has photophobia and neck stiffness

Failure to look for staph aureus septicaemia in a pt in whom staph aureus has grown from a urine culture (i.e. septicaemia came first)

Question 20

Kernig sign

Answer 20

Sign of meningitis (unreliable): severe stiffness of the hamstrings causes an inability to straighten the leg when the hip is flexed to 90 degrees

Question 21

List 5 clinical mistakes made in the Mx of pts with fever

Answer 21

Failures to consider TB in pts who have lived in TB endemic areas

Failure to consider acute HIV infection

Dx of a “viral illness” in the elderly with hidden bacterial sepsis

Failure to consider non-infective causes of fever

Treating fever simply because it’s present

Question 22

In what groups is it particularly dangerous to assume that a pt without a fever does not have a serious infection?

Answer 22

Elderly

Neonates

ESKD

Severe debility

Hypothyroidism

Taking anti-inflammatories

Question 23

3 reasons FOR treating fever

Answer 23

Potential for aggravating HF, or precipitating premature labour if high fever is untreated

Fever >40 degrees confers risk of CNS and other injury

Patient discomfort

Question 24

3 reasons for NOT treating fever

Answer 24

Fever is part of host defence infection

Treatment may obscure response to Abx

Treatment with antipyretics (paracetamol, NSAIDs, aspirin) can have AEs (note that paracetamol can cause sweating, which some pts find worse than a high fever!)

Question 25

Do NSAIDs have an effect on mortality?

Answer 25

Did not improve survival in pts with sepsis even though body temp was reduced

Animal models showed increased mortality with antipyretics

Question 26

What types of conditions can cause temp >41 degrees?

Answer 26

Usually NOT infection

Malignant hyperthermia

Heat stroke

Cerebral bleed or tumour

IV pyrogen reaction

Question 27

MT, 70, attended ED after seeing GP the previous day, complaining of 6/52 of hip and upper arm and neck stiffness, headaches, anorexia and lethargy; has also had recent 3kg LOW but no jaw claudication

Ix from GP: CRP 160, Hb 97 (MCV 88), Plt 428, ALP 425 (WCC, UEC, transaminases all normal)

O/E: temp 37.8

PHx: smoker, HTN, depression, DM, hyperlipidaemia

Rx: enalapril, sertraline, atorvastatin for 6/12, DM controlled by diet (but tests BGLs infrequently)

SHx: lives alone, no recent travel, hobbies, animal contacts

DDx?

Answer 27

Disseminated TB

Myalgia from statin

Bone cancer

GCA