Systematic, non-specific defensive response secondary to infection or tissue damage indicated by high body temperature (38.3C or greater)
Fever
What is responsible for Body Temp Regulation?
Hypothalamus
Specifically the Anterior Hypothalamus, which receives information from Central and Peripheral Thermoceptors in the body.
What is the Normal Temperatures for:
- Oral
- Rectal
- Axillary
- Tympanic
- Oral = 35.8 - 37.3C (96.4 - 99.1F)
- Rectal = 36.1 - 37.4C (97.6 - 99.3F)
- Axillary = 36.5 - 37.4C (97.5 - 99.3F)
- Tympanic = 35.8 - 37.5C (96.4 - 99.5F)
T/F: Fevers are usually highest in the morning.
False!
Fevers are usually higher in the evening, so you want to monitor temperature throughout the day.
Afebrile temps in the morning doesn’t mean the pt is afebrile.
Main causes of Fever
- Infections (20-40%)
- Neoplasms (7-20%)
- Collagen Vascular Dz (15-25%)
- Miscellaneous Dz
- Fever of Unknown Origin (FUO)
T/F: Literature suggests that between 5 and 15% of FUO cases defy the diagnosis.
True
Endogenous Mechanism of Fever:
- Interleukin-1 (IL-1) released by the macrophage
- Tumor Necrosis Factor released from cells (macrophages, mast cells, or endothelial cells)
Exogenous Mechanism of Fever:
- Phagocytosis destruction of bacteria and release of the endotoxin LPS (Lipopolysaccharide)
Beneficial Effects of Fever
- Helps set up specific defense (production of T-Cells)
- Speeds up metabolism for tissue repair
- Increases the antiviral effect of interferons
T/F: Healthy individuals can tolerate temperatures up to 110F (43.33C) without ill effects.
False, 105F (40.5C)
Consequences of Fever
- Children can get convulsions
- Elderly can get Myocardial Failure, Ischemia, or Shock
- Immunocompromise
At what temperature is someone dx with EXTREME hyperthermia?
108F (42.22C)
What can Extreme Hyperthermia cause?
- Endothelial Vascular Damage
- Disseminated Intravascular Coagulation (DIC)
- Metabolic Derangements
- Hypoxia
- Seizures/Coma
Things to think about when someone presents with a Fever:
- Host Factors (Vulnerable? Toxic?)
- What could cause this?
- Symptoms?
- Pattern of Fever
- Drug use?
- Hypersensitive?
Sign/Symptoms
- Sometimes asymptomatic
- Warmth/Flushing
- Malaise/Myalgia
- Fatigue
- Chill/Rigor
- Stupor/Lethargy
- Convulsions
- Tachycardia
When should you treat a fever immediately?
- Children because of their tendency for febrile convulsions
- Patient has a serious primary dz like heart, lung, or kidney dz
T/F: When treating a fever, the goal of therapy is to reduce body temperature back to “normothermia.”
False! That does not need to be the goal!
Goal: Reduced to the extent that subjective symptoms improve but the beneficial effects remain.
If patient is hyperpyrexic or hyperthermic, what would your treatment be?
- Physical Cooling
- Salicylates or Acetominophen
In practice, once you have treated a patient for fever, what are you wanting to see to fulfill the goal of therapy?
Temp decrease by 1-1.5C around 1-2 hours after drug administration
Fever without any clear focal symptoms or focal findings could indicate what?
Septicemia of pneumococcal or other etiology.
What should we do if an baby less than 3 months old presents with a fever?
- Fever can cause serious fulminant dz, so don’t leave this alone
- Observe the child’s neurological symptoms and alertness (Think Meningitis)
- Hospital-level investigation is usually necessary!!! (But if treating outpt, make sure the parents can contact the doctor immediately in case of emergency)
What is the most common cause of fever and how would this present?
Viral
Presentation:
- Runny Nose
- Sore Throat
- Cough
- Hoarseness
- Myalgia
Sometimes:
- Diarrhea
- Nausea
- Vomiting
Presentation of Fever of Bacterial Origin in the CNS:
- Headache
- Neck Stiffness
- Confusion
Presentation of Fever of Bacterial Origin in the LRI:
- Coughing
- Difficulty Breathing
- Thick Mucus Production
- Chest Pain (sometimes)
