Pediatric fever of uncertain source

Background

  • Fever accounts for 30% of pediatric visits
  • Children <3 months are immunocompromised (e.g. poor opsonization, poor IgG response to encapsulated bacteria, macrophage and neutrophil dysfunction, bone marrow insufficiency)
  • Concern is for missing a serious bacterial infection (SBI)

Epidemiology and Risk

Age 0-14 days 14-28 days 28-60 days (pre vaccine) 28-60 days (post vaccine) 60-90 days > 90 days
Meningitis/SBI Prevalence 1/10 1/20 1/100 1/1000 1/1000-10,000 > 1/10,000
  • Serious bacterial illness (SBI) includes UTI, meningitis, pneumonia, bacteremia
  • 7% of patients <2 years old with fever have pneumonia, however the etiology (viral/bacterial) or even the presence of pneumonia has low inter-observer reliability even among pediatric radiologists[1]
  • 4% Prevalence of UTI with common other sources of fever (OM, viral URI, etc)[2]
  • 0.3% of previously well children aged 3-36 months who have a fever without a source will develop significant sequelae, 0.03% will develop sepsis or meningitis[3]

Concomitant Respiratory Viral Infection

  • Relatively high coincidence of RSV, enterovirus, and paraflu with bacteremia (and UTIs), so positive lab test for these viruses should not change testing and management plan[4]
    • RSV+ neonates aged 0-28 days, 3.7% were bactremic (and 6.1% had UTIs)
    • RSV+ infants aged 29-60 days, (5.5% had UTIs)
  • There is a low coincidence of influenza with SBI, so postivie lab test for this virus may change testing and management plan (i.e. lower risk of concurrent bacterial illness)[5]

Clinical Features

  • Febrile
    • Defined as temperature ≥38°C (100.4°F).
    • Peripheral temperature is not clinically accurate and central measurements are the preferred means of determining fever.
    • Parental report of confirmed fever at home (i.e. via thermometer), even with no fever in ED, has rates of SBIs high as 4.7% (0-28 day range)[6]

Differential Diagnosis

Pediatric fever

Evaluation & Management

  • Preemies: Count age by estimated postconception date (not by actual delivery date) for 1st-90d

0-7 Days

For all infants (toxic and well-appearing)

Child Appearance Work Up Treatment Disposition & Follow-up Comments
Temperature ≥38°

Toxic or Well

  • CBC
  • Blood cultures
  • Urinalysis, Urine culture
  • LP-CSF
  • CXR
  • +/- Stool studies (if diarrhea)
Admit SBI incidence
  • Ill appearing: 13%–21%
  • Not ill appearing: <5%

^Acyclovir if:

  • HSV infection in baby or mother
  • CSF pleocytoisis
  • Concerning skin lesions
  • Seizures
  • Abnormal LFTs

Note:

  • CXR is optional if no resp sx and another source identified
  • LP is necessary even if another source identified due to immature blood-brain barrier
  • Do not give ceftriaxone to children <28d as may cause hyperbilirubinemia

8-21 Days[7]

  • For toxic infants, treat for sepsis and admit
  • For well-appearing infants:
8-21 day algorithm
Child Appearance Work Up Treatment Disposition & Follow-up Comments
Temperature ≥38°C

Well-appearing

No evident source of infection

Increased HSV risk

  • Urinalysis, Urine culture
  • Blood culture
  • Inflammatory markers (IMs) - may obtain
  • LP-CSF
  • HSV studies
  • Initiate parenteral antimicrobial(s), including Acyclovir
  • Observe in hospital
  • If pathogen or source identified → Treat infection
  • If all culture results negative at 24-36 hours AND HSV PCR negative → Discontinue antimicrobials; may discharge. Manage for duration of illness.

Consider HSV if:

  • Maternal h/o genital HSV lesions or fever 48 hrs before to 48 hrs after delivery
  • Vesicles, mucous membrane ulcers
  • Seizures
  • Hypothermia
  • CSF pleocytosis + negative gram stain
  • Leukopenia
  • Thrombocytopenia
  • Elevated ALT
Temperature ≥38°C

Well-appearing

No evident source of infection

No increased HSV risk

  • Urinalysis, Urine culture
  • Blood culture
  • Inflammatory markers (IMs) - may obtain
  • LP-CSF
  • Initiate parenteral antimicrobial(s)
  • Observe in hospital
  • If pathogen or source identified → Treat infection
  • If all culture results negative at 24-36 hours → Discontinue antimicrobials; may discharge. Manage for duration of illness.

22-28 Days[8]

  • For toxic infants, treat for sepsis and admit
  • For well-appearing infants:

22-28 day algorithm


Child Appearance Work Up Treatment Disposition & Follow-up Comments
Temperature ≥38°C

Well-appearing No source of infection Abnormal IMs CSF pleocytosis or uninterpretable

  • Urinalysis, Urine culture (bladder catheterization or SPA if UA positive)
  • Blood culture
  • Inflammatory markers (IMs)
  • Perform LP(11b) - CSF
  • Administer IV antibiotics
  • Observe in hospital
  • If pathogen or source identified → Treat infection
  • If all cultures negative at 24-36 hours and HSV PCR negative (if sent) → Discontinue IV antibiotics; may discharge. Follow for duration of illness.
Abnormal Inflammatory Markers:
  • Temp > 38.5
  • Procalcitonin > 0.5 ng/mL
  • CRP ≥ 20 mg/L
  • ANC > 4500 or 5200
Temperature ≥38°C

Well-appearing No evident source of infection Abnormal IMs No CSF pleocytosis (or CSF not obtained)

  • Urinalysis, Urine culture (bladder catheterization or SPA if UA positive)
  • Blood culture
  • Inflammatory markers (IMs)
  • Perform LP - CSF (may not be obtained)
  • If observation at home: Administer IV antibiotics
  • If observation in hospital: May administer IV antibiotics
  • If observation at home: Observe at home. Reassess in 24 hours.
  • If observation in hospital: Observe in hospital).
  • If pathogen or source identified → Treat infection
  • If all cultures negative at 24-36 hours and HSV PCR negative (if sent) → Discontinue IV antibiotics; may discharge. Follow for duration of illness.
Temperature ≥38°C

Well-appearing No evident source of infection Normal IMs LP performed, CSF obtained, CSF pleocytosis or traumatic

  • Urinalysis, Urine culture (bladder catheterization or SPA if UA positive)
  • Blood culture
  • Inflammatory markers (IMs)
  • May perform LP - CSF
  • May administer IV antibiotics
  • Observe in hospital
  • If pathogen or source identified → Treat infection
  • If all cultures negative at 24-36 hours and HSV PCR negative (if sent) → Discontinue IV antibiotics; may discharge. Follow for duration of illness.
Temperature ≥38°C

Well-appearing No evident source of infection Normal IMs LP performed, CSF obtained, no CSF pleocytosis/not traumatic OR CSF not obtained OR LP not performed

  • Urinalysis, Urine culture (bladder catheterization or SPA if UA positive)
  • Blood culture
  • Inflammatory markers (IMs)
  • May perform LP
  • If observation at home: Administer IV antibiotics
  • If observation in hospital: May administer IV antibiotics
  • If LP performed but CSF not obtained, or LP not performed: May administer IV antibiotics); Observe in hospital
  • If observation at home: Observe at home. Reassess in 24 hours.
  • If observation in hospital: Observe in hospital.
  • If pathogen or source identified → Treat infection
  • If all cultures negative at 24-36 hours and HSV PCR negative (if sent) → Discontinue IV antibiotics; may discharge. Follow for duration of illness.

29-60 Days[9]

  • For toxic infants, treat for sepsis and admit
  • For well-appearing infants:
29-60 day algorithm
Child Appearance Work Up Treatment Disposition & Follow-up Comments
Temperature ≥38°C

Well-appearing No evident source of infection

Abnormal IMs

  • Urinalysis (obtain for all)
  • Blood culture (obtain for all)
  • Inflammatory markers (IMs) (obtain for all)
  • Send bladder catheterization or SPA urine culture if positive urinalysis (15)
  • May perform LP (18a)
  • If CSF result is positive: Administer parenteral antimicrobial(s) (19a)
  • If CSF result is negative and either urinalysis negative or positive: May administer parenteral or oral antimicrobial(s) (19b)
  • If CSF not available or uninterpretable: Administer parenteral antimicrobial(s) (19a)
  • If CSF result is positive: Observe closely in hospital (20a)
  • If CSF result is negative and either urinalysis negative or positive: May observe closely in hospital or at home (20b,d)
  • If CSF not available or uninterpretable: May observe closely in hospital or at home (20b)
Abnormal Inflammatory Markers:
  • Temp > 38.5
  • Procalcitonin > 0.5 ng/mL
  • CRP ≥ 20 mg/L
  • ANC > 4500 or 5200
Temperature ≥38°C

Well-appearing No evident source of infection

Normal IMs Positive urinalysis result

  • Urinalysis (obtain for all)
  • Blood culture (obtain for all)
  • Inflammatory markers (IMs) (obtain for all)
  • Send bladder catheterization or SPA urine culture (15)
  • Need not perform LP (18b)
  • Administer oral antimicrobial(s) (19c)
  • May observe closely at home
  • Follow-up in 12 to 24 hours (20d)
Temperature ≥38°C

Well-appearing No evident source of infection

Normal IMs Negative urinalysis result

  • Urinalysis (obtain for all)
  • Blood culture (obtain for all)
  • Inflammatory markers (IMs) (obtain for all)
  • Need not perform LP (18b)
  • Need not administer antimicrobial(s) (19d)
  • Observe closely at home (20c)
  • Follow-up within 24-36 hours (20c)

At 24 to 36 hours follow-up:

  • If pathogen or source identified at 24-36 hours AND source limited to urine → Complete treatment with oral antimicrobials (21c); Discharge hospitalized infants (21b); Manage for duration of illness
  • If pathogen or source identified at 24-36 hours AND source NOT limited to urine → Treat infection (21d)
  • If NO pathogen or source identified at 24-36 hours → Discontinue antimicrobials if administered (21a); Discharge hospitalized infants (21b); Manage for duration of illness

60 Days - 36 Months[10]

Appearance Work Up Treatment Disposition & Follow-Up
T≥38° + Toxic Admit
T≥39°C + Well + Non-complete Prevnar

(No Prevnar or <4 weeks post 1st Prevnar dose)

If WBC(+): Outpatient (24 hour follow-up)
T≥39°C + Well + Prevnar

(2 Prevnar or ≥4 weeks post 1st Prevnar dose)

  • Urine workup (UA, urine culture) for:
    • Circumcised males <6 months
    • Uncircumcised males <12 months
    • All females
  • +/- CXR
Treat cystitis or pneumonia if postitive Outpatient (48hour follow up)
T≥38-38.9°C + Well Consider UA, CXR based on symptoms, etc Treat cystitis or pneumonia if positive Outpatient (48-72 hour follow-up)[11]
  • Consider CXR for:
    • Respiratory symptoms
    • Fever >48 hrs
    • Tachypnea
    • Hypoxia
  • Non-UTI SBI incidence of <.4% in children >6 mo

Low Risk Lab Criteria

If low-risk criteria below not met, then perform the LP (if not done) and admit for inpatient antibiotics[12][13]

CBC

  • WBC 5-15 /mm3
  • Absolute Band count <1500 /mm3
  • Procalcitonin ≤0.5 ng/mL
  • ANC ≤4000/mm3

Urinalysis

  • Clear
  • Neg Nitrate and Leukocyte esterase
  • WBC <10/high powered field

CSF

  • Studies should include WBC, protein, glucose, Gram stain, and culture for bacteria. Consider viral studies (HSV).

0-28 days

  • WBC: 0-22/mm3
  • Protein: <100mg/dL

>29 days

  • WBC 0-7/mm3
  • Protein: 15-25mg/dL

Additional Management

Initial Empiric Antibiotics for Well-Appearing Infants

Neonatal Antibiotics by Source[14]

Suspected Infection Source 8-21 Days Old 22-28 Days Old 29-60 Days Old
UTI
  • Ampicillin IV or IM (150 mg/kg per day divided q8) AND either:
No source identified
  • Ampicillin IV or IM (150 mg/kg per day divided q8) AND either:
Bacterial meningitis
  • Ampicillin IV or IM (300 mg/kg per day divided q6) AND
  • Ceftazidime IV or IM (150 mg/kg per day divided q8)
  • Ampicillin IV or IM (300 mg/kg per day divided q6) AND
  • Ceftazidime IV or IM (150 mg/kg per day divided q8)


Acetaminophen Pediatric Dosing Chart

Weight (kg) Weight (lbs) Age Dosage (mg)
3-4 6-11 0-3 mo 40
5-7 12-17 4-11 mo 80
8-10 18-23 1-2 y 120
11-15 24-35 2-3 y 160
16-21 36-47 4-5 y 240
22-26 48-59 6-8 y 320
27-32 60-71 9-10 y 400
33-43 72-95 11 y 480
Dosage can be given q6 hours

See Also

External Links

References

  1. ACEP's Clinical Policy on Pediatric Fever. Clinical Policy for Children Younger Than Three Years Presenting to the Emergency Department With Fever. Annuals of Emergency Medicine 2003 42. 530-545
  2. ACEP's Clinical Policy on Pediatric Fever. Clinical Policy for Children Younger Than Three Years Presenting to the Emergency Department With Fever. Annuals of Emergency Medicine 2003 42. 530-545
  3. ACEP's Clinical Policy on Pediatric Fever. Clinical Policy for Children Younger Than Three Years Presenting to the Emergency Department With Fever. Annuals of Emergency Medicine 2003 42. 530-545
  4. Greenes, D.S.M., & Harper, M. B.M. (1999). Low risk of bacteremia in febrile children with recognizable viral syndromes. Pediatric Infectious Disease Journal, 18(3), 258-261.
  5. Greenes, D.S.M., & Harper, M. B.M. (1999). Low risk of bacteremia in febrile children with recognizable viral syndromes. Pediatric Infectious Disease Journal, 18(3), 258-261.
  6. Serious bacterial infections in neonates presenting afebrile with history of fever Ramgopal S, Walker LW, Tavarez MM, et al. Pediatrics. 2019;144(2):e20183964.
  7. Evaluation and Management of Well-Appearing Febrile Infants 8 to 60 Days Old Robert H. Pantell, Kenneth B. Roberts, William G. Adams, Benard P. Dreyer, Nathan Kuppermann, Sean T. O'Leary, Kymika Okechukwu and Charles R. Woods; Subcommittee On Febrile Infants Pediatrics July 2021, e2021052228; DOI: https://doi.org/10.1542/peds.2021-052228
  8. Evaluation and Management of Well-Appearing Febrile Infants 8 to 60 Days Old Robert H. Pantell, Kenneth B. Roberts, William G. Adams, Benard P. Dreyer, Nathan Kuppermann, Sean T. O'Leary, Kymika Okechukwu and Charles R. Woods; Subcommittee On Febrile Infants Pediatrics July 2021, e2021052228; DOI: https://doi.org/10.1542/peds.2021-052228
  9. Evaluation and Management of Well-Appearing Febrile Infants 8 to 60 Days Old Robert H. Pantell, Kenneth B. Roberts, William G. Adams, Benard P. Dreyer, Nathan Kuppermann, Sean T. O'Leary, Kymika Okechukwu and Charles R. Woods; Subcommittee On Febrile Infants Pediatrics July 2021, e2021052228; DOI: https://doi.org/10.1542/peds.2021-052228
  10. Jaskiewicz, J.A., McCarthy, C.A., Richardson, A.C., White, K.C., Fisher, D.J., Powell, K. R., et al. (1994). Febrile infants at low risk for serious bacterial infection-an appraisal of the Rochester criteria and implications for management. Pediatrics 94(3), 390-396.
  11. Baker, M.D., Bello, L.M., & Avner, J.R. (1993). Outpatient management without antibiotics of fever in selected infants. New England Jouranl of Medicine, 329(20), 1437-1441.
  12. Smitherman, H.F. & Macias, C.G. (2014). Evaluation and management of fever in the neonate and young infant (less than three months of age) [Electronic Version]. UpToDate,Teach, S.J., Kaplan, SL, Wiley, JF.
  13. Dagan, R. Sofer, S., Phillip, M., & Shachak, E. (1988). Ambulatory care of febrile infants younger than 2 months of age classified as being at low risk for having serous bacterial infections. Journal of Pediatrics, 112(3), 355-360.
  14. Evaluation and Management of Well-Appearing Febrile Infants 8 to 60 Days Old Robert H. Pantell, Kenneth B. Roberts, William G. Adams, Benard P. Dreyer, Nathan Kuppermann, Sean T. O'Leary, Kymika Okechukwu and Charles R. Woods; Subcommittee On Febrile Infants Pediatrics July 2021, e2021052228; DOI: https://doi.org/10.1542/peds.2021-052228