8. Fever Flashcards
where is body temp controlled?
in preooptic area of hypothalamus
how is blood temperature changed?
vasomo change
shivering
change in metabolic heat production
behavioural change
“Significant fever” Rosen’s defn
> 38.3
Hyperthermia defn
elevation of the tem- perature related to the inability of the body to dissipate heat
typically if gr than 41
Fever defn
elevation of body temperature caused by thermoregulatory path- ways in response to infections and certain other medical circumstances
Examples of endogenous pyrogens (causing fever)
ck released by leukocytes in response to inf, inflamm, neoplastic processes
Exogenous pyrogen examples
bacterial and viral products, toxins
How do toxins induce fever?
stimulating cells of imm system to release endog pygorens like CK IL1, 6, TNF and interferon to hypothal to induce PGE2
this then incr set point of temp range
DDX of noninfectious causes of fever - critical ddx 8
AMI
PE or infarct
ICH
cva
NMS
thyroid storm
acute adrenal insuff
transfusion rxn
pulmonary edema
DDX of noninfectious causes of fever - emergent dx
HF
dehydration
recent seizure
sickle cell disease
transplant rejection
pancreatitis
dvt
DDX of noninfectious causes of fever - nonemergent dx 6
drug fever
malignancy
gout
sarcoid
crohn’s
postmyocardiotomy syndrome
what demographics/factors blunt febrile response?
age
malnutrition
immunosuppression
chronic disease
What positive effects does fever add?
incr chemotaxis
decr microbial replication
improve lymphocyte function
inhibit growth of some bacteria and viruses
what causes chills?
mismatch between set point temp of the hypothalamus is incr and body temp remains N
DDX Infectious causes of fever -respiratory - critical
bacterial pneumonia with resp failure