Fever Flashcards
Describe the effect of body site on temperature
Pulmonary artery > tympanic membrane > oral
What is the gold standard for measuring core body temperature?
Pulmonary artery temperature
When should axillary temperature be used?
Unreliable in adults and should NOT be used
What factors may impact oral temperature?
Site within mouth
Whether mouth previously open or closed
List 8 signs of a severe infection
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
How many blood cultures should be taken and where from? How much blood in each bottle?
2 sets from 2 sites
10mL of blood from adults
Define PUO
Illness >3 weeks
Fever >38.3C
No diagnosis after intelligent assessment
What is the most common cause of PUO?
Infection
When is temperature lowest throughout the day? When is it highest?
Early morning
Highest around late afternoon/evening
What are the key questions to ask when assessing a patient with fever?
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
What constitutes a temperature?
>37.1 in early morning
>37.7 in late afternoon/evening
List 5 warning bells on Hx in patients with fever
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
What are the key findings to look for O/E in a patient with fever?
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
List 6 warning bells in examination of patients with fever
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)
6 non-specific Ix in patient with fever (may not all be necessary, depending on initial clinical assessment)
FBE
UEC
LFTs
BGL
Blood gases (if patient shocked, in possible acidosis or respiratory failure)
CRP
9 more specific Ix in patient with fever (dependent on initiSaveal clinical assessment)
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)
What key Mx decisions must be considered in the initial treatment of the patient with fever?
Empiral Abx?
ICU support?
Is an urgent intervention to drain a septic focus or prosthesis required?
List 14 syndromes presenting with fever which may require urgent treatment
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
5 common Dx mistakes made in Mx of patients with fever
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)
Kernig sign
Sign of meningitis (unreliable): severe stiffness of the hamstrings causes an inability to straighten the leg when the hip is flexed to 90 degrees
List 5 clinical mistakes made in the Mx of pts with fever
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
In what groups is it particularly dangerous to assume that a pt without a fever does not have a serious infection?
Elderly
Neonates
ESKD
Severe debility
Hypothyroidism
Taking anti-inflammatories
3 reasons FOR treating fever
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
3 reasons for NOT treating fever
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!)
Do NSAIDs have an effect on mortality?
Did not improve survival in pts with sepsis even though body temp was reduced
Animal models showed increased mortality with antipyretics
What types of conditions can cause temp >41 degrees?
Usually NOT infection
Malignant hyperthermia
Heat stroke
Cerebral bleed or tumour
IV pyrogen reaction
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?
Disseminated TB
Myalgia from statin
Bone cancer
GCA
