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Flashcards in Management of Fever Deck (70):
1

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

2

What are the 6 methods of taking body temperature?

Rectal
Ear
Oral
Forehead
Axillary
Transcutaneous

3

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)

4

A fever is generally accompanied by what?

Mild dehydration, febrile seizures, delirium and discomfort (reassure parents; monitor; and refer to physician if necessary)

5

What is considered above normal temperature?

Rectal: above 38ºC
Oral: above 37.5ºC
Axillary: above 37.3ºC
Tympanic: above 38ºC

6

What is the recommended technique for measuring temperature from birth to two years?

1. Rectal
2. Axillary
Tympanic is not recommended

7

What is the recommended technique for measuring temperature from 2 to 5 years old?

1. Rectal
2. Axillary, tympanic

8

What is the recommended technique for measuring temperature for children older than 5?

1. Oral
2. Axillary, tympanic

9

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

10

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

11

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

12

What are exogenous pyrogens?

Chemicals produced by bacteria or by components of the organism. Stimulate the release of endogenous pyrogens

13

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)

14

What is hyperthermia?

An increase in body temperature not due to the hypothalamus (i.e., physical exertion)

15

What are risk factors?

Bacterial infection
Viral infection
Cancer
Multisystem diseases
Medications

16

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

17

What are signs and symptoms associated with fever

Sweating
Headache
Malaise and fatigue
Backache, myalgia and arthralgia
Dehydration
Discomfort
Febrile seizures

18

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

19

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

20

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

21

What is fever phobia?

Unrealistic concerns and misconceptions that can result in heightened anxiety and inappropriate treatment of fever

22

What do antipyretics do?

Antipyretic agents reduce body temperature in febrile patients via decreasing prostaglandin synthesis by inhibiting the cyclo-oxygenase (COX) enzyme

23

Can acetaminophen and ibuprofen be used for a fever?

They are the the only therapeutic choices for managing a fever in children

24

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)

25

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

26

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

27

What is the adult dosing for acetaminophen?

325-650 mg q4-6h PRN (max 4g/24 hours)
New dosing guidelines being discussed

28

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)

29

How safe is acetaminophen?

Generally, considered a safe analgesic
Relatively safe for short term use in children, pregnancy and lactation
Dosing adjustment may be necessary for patients with renal dysfunction but not in the elderly

30

What are the adverse reactions of acetaminophen?

Adverse effects are considered rare. They include: allergic reaction, nausea and upper GI discomfort, serious skin reactions

31

What are clinically important drug interactions of acetaminophen?

Alcohol (increased hepatotoxicity)
Enzyme inducers (decreased acetaminophen levels)
Chronic use can occasionally enhance warfarin's anticoagulant effect (rare)

32

What are possible causes for acetaminophen toxicity

Overdose
Disease and lifestyle (hepatitis, liver disease (cirrhosis), chronic alcohol use, binge drinking and fasting)

33

What are the available dosage forms of acetaminophen?

Immediate release tablet/caplet
Extended-release caplet
Gelcap
Chewable tablet
Rapidly-dissolving tablet
Liquid
Rectal suppository

34

What are NSAIDs? What are examples of NSAIDs?

Non-steroidal anti-inflammatory drugs
Acetylsalicylic acid, ibuprofen, naproxen

35

What are the pharmacological properties of NSAIDs?

Analgesic, antiplatelet, antipyretic, anti-inflammatory (may require higher doses than often seen in OTC)

36

What is the MOA of ibuprofen?

Inhibits the COX enzyme in the periphery and CNS and thereby inhibits prostaglandin synthesis
It is a safe and effective analgesic and antipyretic, causes a 1-2ºC decrease in temperature

37

What is the OOA of ibuprofen?

Antipyretic: over an hour
Analgesic: within 60 minutes
Anti-inflammatory: 7 days or more (peak effect: 1-2 weeks)

38

What is the DOA of ibuprofen?

Time to peak: 2-4 hours
Duration: 6-8 hours

39

How is ibuprofen metabolized?

Liver

40

What is the adult dosing for ibuprofen?

For a fever: 200-400 mg/dose q4-6h PRN
Max: 1.2 g/day

41

What is the paediatric dosing for ibuprofen?

PO 5-10 mg/kg q6-8h PRN
Max: 40 mg/kg/day or 4 doses/24 hours

42

What are the adverse effects of ibuprofen?

Most frequent: abdominal pain with cramps, dizziness, heartburn, nausea, skin rash
Sodium and water retention, diarrhea, GI bleeding, headache, nervousness, allergic reactions, reduced renal function, acute renal failure

43

What are contraindications/precautions for ibuprofen?

CI/precaution: PUD, GI perforation or bleeding, hypersensitivity, bleeding disorders, concomitant alcohol use, patients relying on vasodilatory renal prostaglandins for renal function
Caution: CHF, hypertension, dehydration, decreased renal

44

What are the drug interactions of ibuprofen?

It can reduce ASA's anti platelet effect
It can increase the risk of GI pain/ulceration when taken with alcohol and/or corticosteroids
Antihypertensive agents (the antihypertensive effect is inhibited, possible hyperkalemia)
Increase the risk of bleeding with anticoagulants
Increase the risk of nephrotoxicity with cyclosporine
It can increase the levels of lithium and/or methotrexate

45

What are the consequences of overdose?

Serious toxicity is unusual
GI disturbances, bleeding, CNS depression, bradycardia, seizures, drowsiness, liver dysfunction, hypotension, death

46

Children who are at greatest risk of ibuprofen related renal toxicity include what?

Dehydrated (avoid in children with diarrhea and vomiting)
Cardiovascular disease
Pre-existing renal disease
Concomitant use of other nephrotoxic agents
Those younger than 6 months

47

Can be ibuprofen be taken while pregnant/breastfeeding?

There's a risk in the first and third trimester
It's compatible with breastfeeding

48

What are the dosage forms of ibuprofen?

Tablets, caplets
Gel caplets, liquid-gels
Paediatric drops
Children's suspension
Chewable tablets

49

What is the MOA of ASA?

Inhibits the COX enzyme in the periphery and CNS

50

What is the OOA and DOA of ASA?

Onset: Within an hour
Time to peak: 3 hours
Duration: 4-6 hours

51

Can be ASA be used in children?

Not recommended in children. Avoid in children less than 18 years old who have a viral illness (due to Reye's syndrome). The cause of fever is often unknown, therefore avoid ASA in children

52

What is Reye's syndrome?

Rapidly progressive encephalopathy with cerebral oedema, hepatic dysfunction and metabolic derangements which begins several days after apparent recovery from a viral illness (especially varicella or influenza A or B)
Characterized by vomiting and confusion, quickly evolving to seizures and coma
Salicylate use identified as a major precipitating factor

53

What is the adult dosing for ASA?

325-650 mg q4-6h PRN
Max: 4 g/day

54

What are the adverse effects of ASA?

Most frequent: abdominal pain with cramps, heartburn, dyspepsia, GI irritation
GI bleeding, skin rash, allergic reaction, sodium and water retention, platelet dysfunction

55

What are contraindications and precautions for ASA?

Less than 18 years old, active GI lesions, history of recurrent GI lesions, bleeding disorders, hypersensitivity, concomitant alcohol use, patients relying on vasodilatory renal prostaglandins for renal function
Precaution in renal failure and severe hepatic insufficiency

56

What are the drug interactions of ASA?

Increase risk of GI pain/ulceration with alcohol and corticosteroids
Increase risk of gastroduodenal ulcers and bleeding with NSAIDs
Antihypertensives (antihypertensive effect is inhibited, possible hyperkalemia)
Increased risk of bleeding with anticoagulants
Increase levels of methotrexate
Decreased therapeutic effect of probenecid and sulfinpyrazone

57

What are signs of ASA overdose?

Tinnitus, hyperpyrexia, hyperventilation, acid-base disturbances, nausea/vomiting, dehydration, coma, seizures, bleeding, hepatoxicity, renal failure, hyper or hypoglycemia, death

58

Is ASA safe in pregnancy/breastfeeding?

Risk in first and third trimester (compatible at low doses)
Potential toxicity in breastfeeding

59

What is ASA-induced asthma?

30 minutes to 3 hours post ingestion of ASA, it's possible to observe clinical syndrome characterized by the onset of asthma
It's common in 5-20% of asthmatics with concomitant allergic rhinitis or nasal polyps
Prosposed mechansim: decrease in prostaglandins results in an increase in leukotrienes (important mediator in asthma and allergies)

60

What is the MOA of naproxen?

Same as ibuprofen
For adults only

61

What is the dosing for naproxen for adults 12-65 years?

1 tab (220 mg) q8-12h
Max 2 tabs in a 24 hour period

62

What is the dosing for naproxen for adults over 65 years?

q12h
Max 2 tabs in a 24 hour period

63

What is the OOA of naproxen?

Unknown for fever (20 minutes for analgesic effects)

64

Is naproxen safe to take in pregnancy/breastfeeding?

Pregnancy risk factor C
Not recommended for breastfeeding

65

Describe renal tolerability of NSAIDs

Prostaglandins (PGs) are important for maintenance of renal blood flow and tubular transport of electrolytes. Increased PG release occurs to compensate for an increased level of angiotensin II and norepinephrine
NSAIDs inhibit this compensatory mechanism therefore they can lead to:
-renal and systemic vascular resistance
-increased BP
-worsening of pre-existing CHF
NSAIDs therefore often interfere with the effects of antihypertensive agents

66

What are the patients at risk of renal failure when using NSAIDs?

Volume depletion states
Severe congestive heart failure
Hepatic cirrhosis (with or without ascites)
Clinically significant dehydration
Creatinine clearance is less than 30 ml/min
Intrinsic renal disease secondary to diabetes nephrotic syndrome or hypertension

67

Should products for treatment of fever be alternated or combined?

It is not recommended due to safety issues with this practise
-risk of overdose
-medication errors due to complexity regimen
-increased side effects

68

What is considered first line for treatment of fever?

Consider acetaminophen first line therapy in:
-ASA-sensitive asthma
-gastritis or PUD
-increased risk of bleeding
-patients with renal dysfunction
-CV or hypertensive patients
-multiple concurrent therapy
-pregnant or breastfeeding (especially third trimester)

69

What are monitoring parameters?

Watch for the development of rash or allergic reactions
Side effects (GI intolerances, tinnitus)
Monitor patients with pre-existing co-morbid conditions (CHF, CV or pulmonary insufficiencies)
Improvement should be seen within 24-72 hours
Treatment should not be used for more than 3 days without referral to determine underlying cause
Comfort is the goal
Monitor for dehydration and seizures in children at risk

70

Should a child be woken up for treatment?

No, unless they are at risk for seizures