fever and SIRS/sepsis II Flashcards
fever (pyrexia or febrile response)
- temp rising above the normal (97.9-98.6)
- 104-105 dangerous –> CNS damage
- 101 F (38.3 C) defined as fever**
- variation depending on where you check it
diurnal variation
- variation of 1 degree F between 6a.m.-6pm
- lowest temp at 6 am
ovulation cycle
-1 degree F lower before ovulation, 1 degree F increase after ovulation until menses
chills and sweats
-shiver/chills when the temp is rising, sweats when the temp is falling
temp control
- controlled by prep-optic region of anterior hypothalamus (also the dorsomedial part)***
- a pyrogen (prostaglandin E2) can act on hypothalamus –> systemic response*
- TNF-a, IL-1,6, IFN-g –> cross blood-brain barrier to reach hypothalamus*
- afferent impulses from PNS also transmit signals from tissues to hypothalamus to regulate temp.*
Diencephalic fits/seizures (“central fevers”)**
- usually after brain injury or hemorrhagic stroke
- have fevers, tachycardia, tachypnea, autonomic dysfunction –> don’t regulate temp well
- hyperthermia in hot room, hypo in cold room
heat stroke (aka sun stroke)**
- produce way more heat than your body can dissipate*
- beta blocker or alcoholics are risk factors*
- temp >104F –> CNS problems, lack of sweating
- treat: physical cooling, IV
malignant hyperthermia**
- autosomal dominant (genetic)**
- exposed to succinylcholine or anesthetic gas***
- high fevers, metabolic acidosis, tachycardia, muscle rigidity (from high Ca2+) –> Hyperkalemia and rhabdomyolysis**
- treat: dantrolene (inhibits Ca2+ release from SR)***
malignant neuroleptic syndrome**
- neuroleptic meds depress the nervous system
- rxn to neuroleptic anti-psychotic or anti-nausea meds* (life-threatening)
- fever, altered mental status, muscle rigidity/tremors, sweating, hyporeflexia
- treat: dantrolene, bromocriptine, diazepam***
- haloperidol** most commonly leads to syndrome
- takes days to occur
serotonin syndrome**
- use of 2 or more serotonergic meds** –> excess serotonin on CNS
- SSRIs are common
- hyperthermic, tachycardia, shiver/sweat, dilate pupils, myoclonus, hyperreflexia*
- treat: benzodiazepines, cyproheptadine
- risk factors: linezolid + SSRI*** –> febrile
- occurs quickly
drug fever**
- meds that can cause fevers and dissipate after discontinuation
- don’t look toxic (septic), but have a high fever***
- caused by antimicrobials or anticonvulsants
lipopolysaccharide (LPS)**
- lipid A endotoxin
- pro-inflammatory cytokine**
- gram neg bacteria (and others) –> release LPS –> release of other cytokines (IL-1,TNFa) –> fever***
other cell walls that cause fever with pro-inflammatory cytokines: peptidoglycan and lipoteichoic acid (Gram-positive organisms) mannan in fungi, lipoarabinomannan in mycobacteria.
pulse-temp. dissociation (Faget’s sign)**
- high fever, but low pulse rate (opposite)**
- pulse should increase by 10 with each 1 temp raise
- seen in SALMONELLA infections**
- also in Legionnaires, mycoplasma, Psittacosis**
fever with night sweats**
- sever night sweats
- also seen in liver and lung abscesses
- due to TB and lymphoma**
noninfectious causes of fever*
- usually in ICU patients
- seen in autoimmune, neoplasms (lymphoma, hypernephroma*, anything metastatic to the liver), gout, stroke, MI
