Management of Fever Flashcards
What is fever?
A normal response to various circumstances - usually due to viral or bacterial infection.
A controlled physiologic response where the core temperature of the body temperature is increased and new balance of heat loss and production is established
It’s a defence system; the body’s immune response to pyrogens
What are the 6 methods of taking body temperature?
Rectal Ear Oral Forehead Axillary Transcutaneous
What defines a fever?
Generally defined as rectal temperature over 38ºC
The degree of the child’s fever may correlate the likelihood of a serious bacterial infection
Generally self-limiting (3 days)
A fever is generally accompanied by what?
Mild dehydration, febrile seizures, delirium and discomfort (reassure parents; monitor; and refer to physician if necessary)
What is considered above normal temperature?
Rectal: above 38ºC
Oral: above 37.5ºC
Axillary: above 37.3ºC
Tympanic: above 38ºC
What is the recommended technique for measuring temperature from birth to two years?
- Rectal
- Axillary
Tympanic is not recommended
What is the recommended technique for measuring temperature from 2 to 5 years old?
- Rectal
2. Axillary, tympanic
What is the recommended technique for measuring temperature for children older than 5?
- Oral
2. Axillary, tympanic
What are some practical points for measuring temperature?
Do not use an oral thermometer for rectal purposes and vice versa
A digital thermometer may be used for either oral or rectal (plastic sheaths are available)
Digital is preferred - convenience (safer, faster, easier) and cost (cheaper in the long run)
Fever strips (transcutaneous method) no longer recommended - not an accurate reading
Describe the pathophysiology of a fever
Fever is produced by pyrogens of either endogenous or exogenous origins
Prostaglandins of E2 series are produced in response to the circulating pyrogens and elevate the thermoregulatory set point in the hypothalamus
Within hours, the body temperature increases the new set point and fever occurs
Body temperature is increased by vasoconstriction of peripheral blood vessels, shivering to increase heat production, behavioural changes
What are endogenous pyrogens?
Proteins that induce fever including chemicals such as interleukin-1, tutor necrosis factor alpha, interleukin-6, ciliary neurotropic factor and interferon gamma
What are exogenous pyrogens?
Chemicals produced by bacteria or by components of the organism. Stimulate the release of endogenous pyrogens
What controls the body’s temperature?
Hypothalamus is the body’s thermoregulatory centre - balancing heat production/dissipation
Fever is controlled by the hypothalamus which increases body temperature when exposed to pyrogens (increased production of prostaglandins)
What is hyperthermia?
An increase in body temperature not due to the hypothalamus (i.e., physical exertion)
What are risk factors?
Bacterial infection Viral infection Cancer Multisystem diseases Medications
When should a patient be referred?
Babies under 6 months
Fever lasting over 72 hours (with out without treatment)
Fever lasting over 24 hours without obvious cause
Fever over 40.5ºC
Child appears very ill, is excessively cranky or irritable, cries inconsolably
Patient has persistent wheezing and cough
Patient has rash with fever (could be life threatening)
Patient is difficult to arouse, confused or delirious, has recently received chemotherapy or has serious underlying disease
Patient had recent surgery or dental procedures, recently travelled or eaten raw or poorly cooked meat/fish or recently started a new drug (associated with hypersensitivity)
Child has any other symptoms that bothers the parents
What are signs and symptoms associated with fever
Sweating Headache Malaise and fatigue Backache, myalgia and arthralgia Dehydration Discomfort Febrile seizures
What are the goals of therapy?
Provide patient comfort
Reduce parental anxiety
Reduce metabolic demand caused by fever in patients with cardiovascular or pulmonary disease
Prevent or alleviate fever-associated mental dysfunction
What are non-pharmacological options?
Remove excess clothing, blankets and bedding (keep person cool and comfortable)
Increase fluid intake to replace water loss from fever produced sweating (prevent dehydration)
Avoidance of extreme physical exertion
Maintain normal room temperature
Should a fever be treated pharmacologically?
There are arguments against treating a fever (it’s part of the body’s defence mechanism)
The decision to use antipyretics must be individualized
The main reason to treat a fever is the patient discomfort associated with fever
What is fever phobia?
Unrealistic concerns and misconceptions that can result in heightened anxiety and inappropriate treatment of fever
What do antipyretics do?
Antipyretic agents reduce body temperature in febrile patients via decreasing prostaglandin synthesis by inhibiting the cyclo-oxygenase (COX) enzyme
Can acetaminophen and ibuprofen be used for a fever?
They are the the only therapeutic choices for managing a fever in children
What is the goal of pharmacological treatment of a fever?
Reduction of the hypothalamic set point
Do not lower “normal” body temperature
Regular/short term use of agents is recommended - intermittent use may cause ‘swings’ in temps (increased metabolic demand)
What is the MOA of acetaminophen?
Acetaminophen reduces fever by inhibiting the formulation and release of prostaglandins in the CNS and by inhibition endogenous pyrogens and the hypothalamic thermoregulator centre
It’s a safe and effective analgesic and antipyretic that causes a 1-2ºC decrease in temperature
What is the onset, time to peak, duration of acetaminophen?
Oral: 30 minutes
PR: slowly and incompletely absorbed
Time to peak: 3 hours
Duration: 4-6 hours
It is extensively metabolized by the liver
It is rapidly and completely absorbed from the GI tract
What is the adult dosing for acetaminophen?
325-650 mg q4-6h PRN (max 4g/24 hours)
New dosing guidelines being discussed
What is the pediatric dosing for acetaminophen?
PO/PR 10-15 mg/kg/dose given q4-6h PRN
Max 65 mg/kg/day (max 5 doses/24 hours)