Fever without a Focus

Question 1

How do antipyretics work?

Answer 1

• The anterior hypothalamus is what maintains a normal body temperature
• pyrogens such as: IL-1, IL-6, , TNF and interferons cause the release of arachidonic acid which is metabolized to prostaglandin E2, raising temp
• Antipyretics inhibit hypothalamic cyclooxygenase and thus decrease prostaglandin E2

Question 2

What is the most common cause of fever in children?

Answer 2

• Viral infection

Question 3

What would be considered a fever?

Answer 3

• RECTAL temperature of 38 degrees Celsius or higher

Question 4

What is the normal temperature range?

Answer 4

36.6 C to 37.9 C

Question 5

Body temperature normally fluctuates. When is it at its highest? lowest?

Answer 5

Highest: Early evening

Lowest: Morning

Question 6

What 3 mechanisms can produce a fever?

Answer 6

1) Pyrogens
2) Heat production exceeding loss
- salicylate toxicity
- malignant hyperthermia
3) Defective heat loss
- Severe heat exposure
- Ectodermal dysplasia

Question 7

Which commonly used antibiotic can cause fever?

Answer 7

• Vancomycin

Question 8

What are the 4 main categories of fever causes?

Answer 8

1) Infectious
2) Inflammatory
3) Neoplastic
4) Misc

Question 9

A temperature above what level is considered to be potentially lethal?

Answer 9

• 42 degrees Celsius in a neurologically intact child

Question 10

What is a tertian fever? What causes it?

Answer 10

• A fever that occurs in cycles on the first and 3rd day and then repeats
• Quartan fever same but 1st and 4th day
• Caused by malaria

Question 11

True or false: Fevers with temperatures under 39 degrees Celsius in healthy children generally do not require treatment

Answer 11

True

• Fever helps reduce infectious load
• Not harmful until higher temperature
• Treatment would be for patient comfort only, does not change course of disease

Question 12

How would you dose acetaminophen in a child?

Answer 12

• 10-15mg/kg/dose

- every 4 hours

Question 13

How would you dose ibuprofen in a child?

Answer 13

5-10mg/kg/dose

- every 8 hours

Question 14

What features would suggest a child under 3 months of age with a fever of unknown focus is at low risk of serious infection or sepsis?

Answer 14

• Age older than 1 month
• Well appearing, no focus
• No hx of prematurity
• No hx of prior antimicrobial therapy
• WBC count between 5000-15000
• Urine WBC < 10 per HPF

Question 15

How do you manage a low risk fever with unknown focus in a patient under 3 months?

Answer 15

1) Follow as outpatient
- within 24 hours or sooner if change
- No antibiotics are needed or can give single IM dose of ceftriaxone

Question 16

In children aged 3-36 months what are risk factors for occult bacteremia?

Answer 16

• Temp 39 or more
• WBC > 15 000
• Elevated absolute neutrophils or bands
• Elevated ESR/CRP

Question 17

Define fever without a focus (AKA Fever without localizing signs)

Answer 17

• Fever in which history and physical examination fail to establish a cause
• Common in children under 3

Question 18

Define Fever of unknown Origin

Answer 18

Meeting one of the following criteria
1) Fever for >14 days without an identified etiology despite history, physical, and routine labs

2) Continued fever for 7+ days while hospitalized and being evaluated