Fever Flashcards
What is the definition of fever?
depends on condition, diurnal variation etc.
for now consider: 37.8-37.9 (for sure >38)
What is the definition of fever in febrile neutropenia?
T>38.3 (oral)
or T>38 (>=1 hr)
What is the definition of fever in FUO (fever of unknown origin)?
T>= 38.3 on multiple readings over 3 weeks
no cause after investigations
On avg where does normal body temperature lie?
36.5-37 dc
What is fever?
What causes fever (pathway)?
an increase in the ‘hypothalamic setpoint’
exogenous pyrogens (bacteria, LPS)–> activated leukocytes–> pyrogenic cytokines: IL-1, TNF, IFN, IL-6–> vascular endothelium (inc PGE2)–> inc in hypothalamic setpoint range –> dec. cutaneous bld flow (chills), shivering to generate heat, thermogenesis from brown fat
Survival of what 2 infx correlates with Tmax of fever?
- Gram negative bacteremia
2. Spontaneous bacterial peritonitis
What are 2 examples of increased body temperature that are not fever?
- Hyperthermia (hypothalamic setpoint unchanged): heat stroke, malignant hyperthermia, neuroleptic malignant syndrome
- Hyperpyrexia (T>41): CNS hemorrhage
What is the Ddx for fever?
- infections
- non-infectious inflammatory disorders (autoimmune connective tissue diseases, auto-inflammatory/periodic fever syndromes)
- malignancy
- vascular thrombosis
- endocrine/metabolic disorders
- drugs/medications
How do most antipyretic work?
COX inhibitors (inhibit Arachidonic acid–>PGE2
What are common anti-pyretics?
- ASA (salicylates)
- acetominophen (Tylenol)
- NSAIDS (ibuprofen, naproxen)
-Corticosteroids–> many actions so DONT USE FOR FEVER
What are the rx for:
- fever
- hyperthermia
- hyperpyrexia
- fever (prolonged/severe): acetaminophen
- hyperthermia: external cooling+specific therapy
- hyperpyrexia: external cooling+anti-pyretics
