Fever

Question 1

What is PUO?

Answer 1

Pyrexia of Unknown Origin

Question 2

how is PUO defined?

Answer 2

Prolonged Illness (2-3 weeks)
Fever (above 38.3C)
No diagnosis after exhaustive investigation

Question 3

what is the normal range for oral temperature?

Answer 3

35.8 - 37.8

Question 4

when is body temperature the lowest?

Answer 4

morning

Question 5

where is body T regulated?

Answer 5

Anterior Hypothalamus

Question 6

mechanisms of heat loss include?

Answer 6

peripheral vasodilation, sweating and reduced physical activity

Question 7

heat production mechanisms include?

Answer 7

shivering and increasing metabolic rate
release of thyroid hormone
glucocorticoids
catecholamines [epinephrine, norepinephrine, dopamine]

Question 8

what is the definition of fever?

Answer 8

oral morning Tem > 37.2

oral Temperature > 37.8

Question 9

what is the difference between oral and axillary Temps with core Temp?

Answer 9

oral <1

Question 10

why is increasing temperature a physiological mechanism?

Answer 10

because some immune activities are best functional at 39.5 [immune, endocrine, physiological]
also bacteria tend to work less effectively at higher temps

Question 11

main inducers of fever?

Answer 11

TNFa
IL-1ß
IL-6
IFN-y

Question 12

how is the effect of cytokines mediated in the anterior hypothalamus?

Answer 12

inducing of COX-2 and breaking down of membrane arachidonic acid to produce PGE2 (prostaglandin)

Question 13

Describe Rigor

Answer 13

feeling of uncontrolled shivering and intense cold sensation with pallor and pilo-erection. Main mechanism used to INCREASE BODY TEMP

Question 14

during the rigor phase of a fever temp is high T/F

Answer 14

F, temp is normal and increases afterwards

Question 15

sudden sustained fever with the patient coming into the ER must be treated by

Answer 15

Resuscitation
stabilisation
Empirical Antibiotics (check for risks in order to establish this)

Question 16

some of the alarm bells that indicate serious infection in re: fever

Answer 16

rapid onset/evolution
rigors
severe muscle pains
impaired conscious state
vomiting (sign of ICP)
severe headache 
rasch
jaundice

Question 17

investigation of acute serious fever

Answer 17

FBE, CRP, renal/liver function
blood culture, urine culture
CXR

Question 18

if WCC and CRP are fine then the patient does not have an infection, specially if it recedes with panadol and IV fluid T/F

Answer 18

F, some parameters only increase around 12 hours

Question 19

for prolonged fever empirical antibiotics are recommended?

Answer 19

NOT, unless Q fever or atypical pneumonia likely

BETTER to test the patient first UNLESS Hx of travel to plasmodium vivas country (2 years B4)

Question 20

clinical approach to PUO

Answer 20

start again
1 onset and duration
2 seek localising symptoms
3 establish severity
4 is there really a fever?
5 obtain info and review all results
6 look for clues, past Hx Fx Mx
7 country of origin
8 travel Hx
9 occupation, animal exposure
10 Secual Hx and IV drug use

Question 21

pyrexia associated with a history of handling cattle

Answer 21

Q fever caused by Coxiella burnetii
respiratory disease The most common manifestation is mild flu-like symptoms with abrupt onset of fever, malaise, profuse perspiration, severe headache, myalgia (muscle pain), joint pain, loss of appetite, upper respiratory problems, dry cough, pleuritic pain, chills, confusion and gastrointestinal symptoms, such as nausea, vomiting and diarrhea. The fever lasts approximately seven to 14 days. can also produce atypical pneumonia

Question 22

what are the most common causes PUO?

Answer 22

30 infectious
30 autoimmune
30 malignancies
10 other

Question 23

what is benign pyrexia?

Answer 23

mild fever with no apparent cause

Question 24

what is the most common cause of malignancy PUO

Answer 24

lymphomas

Question 25

PUO in people with HIV

Answer 25

Mycobacterium avium complex (MAC), CMV or cryptococcus, histoplasma