1 - Fever Flashcards
What is a fever?
- A normal response to various circumstances, usually due to viral or bacterial infection
- Core temperature of the body is increased
What is the definition of a fever in pediatrics?
- Rectal or tympanic temperature above 38 C
- Oral temperature above 37.5 C
What is a good indicator of how serious a fever is in a child?
How the child is acting, not the degree of the fever
What is the recommended temperature measuring technique for children from birth to 2 years?
First - rectum
Second - armpit
Which temperature measuring technique is NOT recommended for children from birth to 2 years?
Tympanic membrane (ear)
What is the recommended temperature measuring technique for children from 2-5 years?
First - rectum
Second - ear; armpit
What is the recommended temperature measuring technique for children older than 5 years?
First - mouth
Second - ear, armpit
What causes a fever?
Pyrogens
What are endogenous pyrogens?
Proteins that induce fever
What are exogenous pyrogens?
Chemicals produced by bacteria or by components of the organism
What do exogenous pyrogens do?
Stimulate the release of endogenous pyrogens
What does the body do when it recognizes pyrogens?
Produces prostaglandins of the E2 series (PGE2) and elevates the thermoregulatory set point in the hypothalamus
How is the core body temperature increased?
- Vasoconstriction of peripheral blood vessels
- Shivering to increase heat production
- Behavioural changes
Which portion of the brain controls a fever?
Hypothalamus
What is hyperthermia?
An increase in body temperature not due to the hypothalamus (ex: physical exertion)
What are the risk factors for a fever?
1) Bacterial infection
2) Viral infection
3) Cancer
4) Multisystem diseases
5) Medications
When would you refer a fever?
- Babies under 6 months
- Fever lasting more than 72 hours
- Fever lasting more than 24 hours with no obvious cause
- Fever over 40.5 C
- Patient has persistent wheezing and cough, or a rash
- Patient has had recent surgery or dental procedures
What are the goals of therapy for a fever?
- Provide patient comfort
- Reduce parenteral anxiety
- Reduce metabolic demand caused by fever in patients w/ CV or pulmonary disease
- Prevent or alleviate fever-associated mental dysfunction in the elderly
Is decreasing the patients temperature a goal of therapy?
No
What are some non-pharms you can recommend?
- Remove excess clothing, blankets
- Increase fluid intake to replace water loss from sweating
- Avoid physical exertion
- Maintain normal room temperature
Is it recommended for patients with a fever to take a cold shower or sponge bath?
No, because it is not getting rid of pyrogens or prostaglandins, so it will just cause the body to shiver to get back up to the new set core temp
What are the arguments against treating a fever?
- It is a defense mechanism against a bacteria or virus
- Generally self-limiting
- A normal physiological response
Why would you want to treat a fever?
Patient discomfort
What do antipyretic agents do?
Reduce body temperature by decreasing prostaglandin synthesis by inhibiting the cyclooxygenase (COX) enzyme
What are the 2 therapeutic choices for managing a fever in children?
Acetaminophen and ibuprofen
How does acetaminophen decrease a fever?
By inhibiting the formulation and release of prostaglandins in the CNS and by inhibition of endogenous pyrogens at the hypothalamic thermoregulator center
What is the oral onset of acetaminophen?
30 minutes
What is the rectal onset of acetaminophen?
Slow, and incompletely absorbed
What is the peak time of acetaminophen?
3 hours
What is the duration of acetaminophen?
4-6 hours
Which organ metabolizes acetaminophen?
Liver
What is the dosing of acetaminophen for adults?
- 325-650 mg every 4-6h
- Max 4g/ 24 hr
What is the dosing of acetaminophen for children?
- 10-15 mg/kg/dose every 4-6 h (not exceeding adult dose)
- Max 65-75 mg/kg/day or max 5 doses/24 hr
Is acetaminophen safe for use during pregnancy?
Yes
Is acetaminophen safe for use during lactation?
Yes
Does acetaminophen have a lot of adverse effects?
No
What are the clinically important drug interactions with acetaminophen?
- Alcohol (increased risk of hepatotoxicity)
- Enzyme inducers (decreased acetaminophen levels)
- Chronic use can occasionally enhance warfarin’s anticoagulant effect
What are 3 common NSAIDs?
- Acetylsalicylic acid
- Ibuprofen
- Naproxen
What are the pharmacological properties of NSAIDs?
- Analgesic
- Antiplatelet
- Antipyretic
- Anti-inflammatory
How does ibuprofen decrease a fever?
Inhibits the COX enzyme in the periphery and CNS, thereby inhibiting prostaglandin synthesis
What is the onset of ibuprofen as a antipyretic?
Less than 1 hour
What is the onset of ibuprofen as an analgesic?
Less than 1 hour
What is the peak time of ibuprofen?
2-4 hours
What is the duration of ibuprofen?
6-8 hours
Where is ibuprofen metabolized?
Liver
What is the adult dosing of ibuprofen for a fever?
- 200-400 mg/dose every 4-6h
- Mac 1.2 g/ day
What is the child dosing of ibuprofen for a fever?
- Over 6 months - 5-10 mg/kg every 6-8h
- Under 6 months - 5 mg/kg every 8h
- Max 40 mg/kg/day or 4 doses/24 hr
What are the most common adverse effects of ibuprofen?
- Abdominal pain w/ cramps
- Dizziness
- Heartburn
- Nausea
- Skin rash
What are some contraindications of ibuprofen?
- Peptic ulcer disease
- GI perforation
- Hypersensitivity
What are some drug interactions with ibuprofen?
- ASA (decreases ASA’s antiplatelet effect)
- Alcohol and corticosteroids (increased risk of GI pain/ulceration)
- Antihypertensive agents
- Anticoagulants (increase risk of bleeding)
- Cyclosporine (risk of nephrotoxicity)
- Lithium, methotrexate
Which children are at the greatest risk of ibuprofen related renal toxicity?
- Dehydrated
- CV disease
- Preexisting renal disease
- Younger than 6 months
Is ibuprofen safe to use during pregnancy?
There is a risk in 1st and 3rd trimesters
Is ibuprofen safe to use while breastfeeding?
Yes
How does ASA decrease a fever?
Inhibits the COX enzyme in the periphery and CNS
What is the onset of ASA?
Within 1 hour
What is the peak time of ASA?
3 hours
What is the duration of ASA?
4-6 hours
Is ASA recommended in children?
NO, has been linked to Reye’s syndrome
What is the adult dosing of ASA?
- 325-650 mg every 4-6 h
- Max 4g/ day
What are the most frequent adverse effects of ASA?
- Abdominal pain with cramps
- Heartburn
- Dyspepsia
- GI irritation
What are some drug interactions with ASA?
- Alcohol and corticosteroids (increase risk of GI pain/ulceration)
- NSAIDs, including COX-2 inhibitors
- Antihypertensive agents
- Anticoagulants (increase risk of bleeding)
- Methotrexate
Is ASA safe to use during pregnancy?
- Yes, in a low dose
- Risk in 1st and 3rd trimesters
Is ASA safe to use while breastfeeding?
Limited data, potential toxicity
What is the proposed mechanism for ASA-induced asthma?
Decreased prostaglandins causes increased leukotrienes
What is ASA-induced asthma?
The onset of asthma 30 mins - 3 hrs post ingestion of ASA
What is another name for naproxen sodium 220 mg?
Aleve
Naproxen has similar indications and method of action as ____
Ibuprofen
Is naproxen safe for children?
No
What is the dosing of naproxen for people 12-65?
1 tab every 8-12h
What is the dosing of naproxen for people over 65 with renal insufficiencies?
1 tab every 12 h
Is naproxen safe to use while pregnant?
No
Is naproxen safe to use while breastfeeding?
Not recommended
Who should not take naproxen?
People allergic to ASA or other NSAIDs
What happens when the levels of angiotensin 2 and norepinephrine rise?
Prostaglandin release is increased
What do NSAIDs often interfere with?
The effects of antihypertensive agents
Is it beneficial to alternate different antipyretics for fever reduction?
No, it is not recommended due to risk of overdose
When is acetaminophen considered the first line therapy?
- ASA-sensitive asthma
- Gastritis or PUD
- Patients w/ renal dysfunction
- CV or hypertensive patients
- Pregnant or breastfeeding
How long should treatment of a fever be continued?
No more than 3 days without referral to determine the underlying cause
Should parents wake a sleeping child so they can take their next dose of medication?
No, unless they are at risk of seizures during the fever
Which antipyretics should be used for children under 18?
Acetaminophen or ibuprofen
