7: Fever Flashcards
(27 cards)
Organ that regulates temperature
Hypothalamus
When is body temp highest and lowest during the day?
Highest in afternoon, lowest in early AM
How much higher is central temp (rectal) than peripheral temp (oral, TM, axillary)?
About 0.5 C higher
Average body temp + definition of fever (according to Carl Wunderlich)
Average temp: 98.6
Fever: 100.4
What can cause less of a fever response in patients?
- Adults >65
- Immunosuppression, corticosteroids
- Several chronic diseases: CKD, hepatic dz
Set point change in fever vs hyperthermia
Fever: set point increases and body temp rises to meet it
Hyperthermia: set point remains unchanged but body temp increases due to environmental heat or body metabolic heat increase
Cytokines in fever vs hyperthermia
Fever: pyrogenic cytokines cause increased heat production or decreased heat loss
Hyperthermia: no pyrogenic cytokines involved
Three examples of hyperthermia
- Heat stroke
- Thyrotoxicosis
- Neuroleptic malignant syndrome
Sepsis definition
Life-threatening organ dysfunction caused by dysregulated host response to infection
Five key findings in Sepsis
- Hypotension
- AMS
- AKI
- Coagulopathy
- Increased respirations
(May or may not present with fever!)
What can cause generalized LAD?
Systemic infection, autoimmune condition, malignancy like leukemia/lymphoma
FUO: Fever of unknown origin
Febrile illness with temp of 101+ for 3+ weeks without an etiology despite 1wk inpatient evaluation
Possible etiologies for FUO
Infection, autoimmune, malignancy, etc.
More common that its an atypical presentation of a common illness, but could be a typical presentation of a rare illness
Normal range for WBC count
3,000 - 11,000 per mm3
What autoimmune has classic low WBC count
SLE
Normal platelet count
140,000 - 450,000
Why does thrombocytopenia sometimes occur in sepsis?
DIC
Four abnormal findings associated with sepsis from CMP
- Increased BUN
- Increased Cr
- Anion gap acidosis
- Liver function test abnormalities
What does a serum lactate over 4 mmol/L mean?
Impaired tissue oxygenation due to tissue hypoperfusion
Two values to look at in a urinalysis looking for infection
Leukocyte esterase + nitrites
Specificity vs sensitivity
Specificity: helps rule things in
Sensitivity: helps rule things out
Mechanism of antipyretics in reducing fever
- COX acts on arachidonic acid -> produces PGE2
2. Antipyretics block COX -> decreases PGE2 -> less action on thermoregulatory center of hypothalamus
Reason to treat fever
Manage sx like HA, myalgia, arthralgias
Common organ system sources of infection in sepsis
Respiratory, GI, GU, skin/soft tissue