(8A) Fever

Fever

• body temperature above normal.

• Fever is usually a normal protective immune response, not a malfunction.

WHAT # IS defining fever

Rectal temperature >100.4°F

Most fevers are

self-limiting + nonthreatening.

Main reason to treat fever?

relieve discomfort, not simply make the temperature normal.

Hyperthermia

malfunction of thermoregulation → excessive heat exposure/production → body overheats

Hyperpyrexia

temperature >106°F → serious mental/physical consequences.

Fever

Pathway

1. Fever-producing stimulus/pyrogen
   → hypothalamus raises temperature set point
   → body feels “too cold” compared with new set point
   → body raises temperature by:

   • Constrict + Shiver + Metabolize

   Then, once body temperature gets too high:
   → body cools itself with:

   • Dilate + Sweat + Breathe

   When the cause/stimulus goes away:
   → set point returns toward normal.

Fever

Causes

• Infectious

  • viruses

  • bacteria

  • fungi

• Noninfectious

  • malignancy / tissue damage

  • metabolic disorders

  • dehydration / heat stroke

  • CNS inflammation

• Drug-related

  • medications can also cause fever

Temperature Measurement

gold standard

Rectal

Rectal equivalents?

Oral + 1°F = rectal

Axillary + 2°F = rectal

Tympanic ≈ rectal

Temporal ≈ rectal

Oral = 103°F, what is equivalent?

104°F

Temperature Technique

overview

• Rectal

• Oral

• Tympanic

• Temporal

• Axillary

Temperature Technique

Rectal

• put a probe cover

• water-soluble lubricant may be used

• infants/young children face down

• adults: insert approximately 0.5–2 inches

• hold until beep

• dispose of cover + clean thermometer.

Temperature Technique

Oral

• wait 20–30 min after eating/drinking

• place under tongue

• close mouth / breathe through nose.

Temperature Technique

Tympanic

• <1 year: pull ear backward

• >1 year: pull back + up

• aim toward patient's eye

• not appropriate for <6 months

Temperature Technique

Temporal

• thermometer may need about 30 min to acclimate to environment

• sweep across forehead as directed.

Temperature Technique

Axillary

• least accurate

• clean/dry armpit

• thermometer touches skin, not clothing.

Temperature Technique

Monitoring rule

During one fever episode:

same site + same thermometer each time.

Fever Complications

• seizure

  • Febrile Seizures

• dehydration

• mental-status changes

More likely with hyperpyrexia >106°F.

Fever Complications

Febrile Seizures

• usually <2 years, peak 18–24 months

• worse with high/fast-rising fever

• antipyretics do NOT prevent recurrence.

Fever Self-Care Exclusions

overview

1. Age/temp

• <3 mo + ANY fever

• >3 mo + ≥104°F

2. Duration

• <2 yr → >24 hr

• >2 yr → >72 hr

4. SICK patient & SCARY symptoms

• Severe infection

• Immunocompromised

• Cardio/lung disease

• CNS/seizure history

• Rash/stiff neck, Dry, Drowsy”

3. fever repeatedly >104°F

Know that fever patients should be assessed using:

QuEST + SCHOLAR-MAC

before deciding whether self-care is appropriate.

Non-Drug Fever Treatment

Recommend:

• FLUIDS: adequate fluids/may need increased fluid intake

• CLOTHES: lightweight clothing

• remove heavy blankets

• COMFORT: comfortable room temperature.

Non-Drug Fever Treatment

Do NOT recommend:

• tepid-water/ice-water bathing/sponging

• hydroalcoholic solutions.

Fever Medications

Mechanism

COX inhibition → ↓ PGE₂ → ↓ fever

Fever Medications

Antipyretics discussed:

• acetaminophen

• NSAIDs - Ibuprofen

• aspirin.

Fever Medications

Acetaminophen (##)

🔴 Children/infants

10–15 mg/kg every 4–6 hr

🔴 Adults

325–1000 mg every 4–6 hr

• Rectal suppository option available.

Fever Medications

Ibuprofen

🔴 Children

5–10 mg/kg every 6–8 hr

Only if >6 months

🔴 Adults

200–400 mg every 4–6 hr.

Fever response

🔴 Maximum temperature reduction occurs around 2 hours after dose.

Fever Medications

Aspirin

• Only if >19 years

  • because of Reye syndrome risk, especially with viral illness/fever.

Fever Medication Errors

• duplicate therapy from combination products

• wrong weight-based calculation

• wrong product concentration.

• wrong measuring device

• wrong dosing interval

Fever Medication Errors

for specific medications…

Acetaminophen

• infant + children's concentrations discussed = same

Ibuprofen

• infant + children's concentrations = different

Fever Counseling

overview

1. Fever phobia

2. Alternating APAP + ibuprofen

3. Vaccines

Fever Counseling

Fever phobia

• Treat discomfort—not just the number on the thermometer.

• A comfortable child does not necessarily need treatment solely because a fever exists.

Fever Counseling

Alternating APAP + ibuprofen

• May reduce fever more, BUT: → increases dosing-error risk

• Professor would reserve this for caregivers who can reliably track dosing.

Fever Counseling

Vaccines

• Before vaccine = NO routine antipyretic, no pretreat

• After vaccine, if pain/fever happens = okay to treat

Adverse-Effect Counseling

SAME AS HEADACHE CHAPTER

APAP

Common:

• stomach upset

Stop/seek care:

• yellow skin/eyes

• bloody stool/vomit

• abnormal bruising/bleeding

• allergic reaction

NSAIDs

Common:

• stomach upset → take with food

Stop:

• severe stomach pain

• bloody stool/vomit

• abnormal bruising/bleeding

• allergic reaction

Salicylates

Common:

• stomach upset

Same serious GI/bleeding/allergy warnings

REFER OR NOT?

Case 1

18-month-old
Oral = 103.5°F

+1°F

→ rectal equivalent = 104.5°F

≥104°F

Case 2

5-year-old
Rectal = 102°F
Fever = 4 days

≥2 years → max 72 hr

4 days >72 hr

Case 3

2-month-old
Tympanic = 101°F

<3 months + fever

Case 1-3 = REFER