Pediatric fever of uncertain source

Background

• Medicine is an art as well as science, practice clinical judgment when using guidelines
• Preemies: Count age by estimated postconception date (not by actual delivery date) for 1st-90d
• If RSV+ or influenza+
  • Low risk of bacterial illness
  • Still some risk of concurrent UTI

Facts and Figures from ACEP's Clinical Policy on Pediatric Fevers

• 7% of patients < 2 years old with fever have PNA, however the etiology (viral/bacterial) or even the presence of pneumonia has low inter-observer reliability even among pediatric radiologists
• 4% Prevalence of UTI with common other sources of fever (OM, viral URI, et cetera)
• 1.5-2% background prevalence of asymptomatic bacteruria in healthy afebrile controls
• 0.3% Rate of occult bactremia with healthy, well-appearing child who has a fever 2-24 months
• 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

Concomitant RSV infection

• In RSV+ (by PCR) neonates aged 0-28 days, 6.1% had UTIs and 3.7% were bactremic; there was no difference in rates of SBI between RSV+ and RSV- neonates in a large prospective multicenter study entailing 1,248 children
• RSV+ infants aged 29-60 days, the SBI rate was 5.5%, all of which were UTIs

Diagnosis & Management

0-28dy

Child Appearance	Work Up	Treatment	Disposition & Follow-up	Comments
Temp ≥38° Toxic or Well	CBC Blood Cx UA, Ucx LP-CSF CXR +/- Stool studies (if diarrhea)	Ampicillin 100 mg/kg AND Gentamicin 5 mg/kg AND/OR Cefotaxime 50-100 mg/kg Acyclovir^ 20 mg/kg	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

28dy-90dy

Appearance	Work Up	Treatment	Disposition & Follow-Up
Temp≥38° + Toxic	CBC Blood Cx UA, Ucx LP-CSF +/- CXR +/- Stool studies (if diarrhea)	Cefotaxime^^ 50-100 mg/kg Ampicillin 100 mg/kg Acyclovir^ 20 mg/kg	Admit
Temp≥°38 + Well	CBC Blood Cx UA, UCx +/- LP-CSF (must do before giving antibiotics) +/- CXR	+/-Ceftriaxone (50-100 mg/kg IM/IV)	Workup(+): Antibiotics and admit Workup(-): ?antibiotics; home with 24 follow-up

^^Can use ceftriaxone 50-100 mg/kg, but concern for bilirubin displacement

• Consider CXR for:
  • Respiratory symptoms
  • Fever >48 hrs
  • Tachypnea
  • Hypoxia

^Acyclovir if:

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

90dy-36mo

Appearance	Work Up	Treatment	Disposition & Follow-Up
T≥38° + Toxic	CBC Blood Cx UA, UCx LP-CSF CXR^	Ceftriaxone (50-100mg/kg) AND Consider vancomycin (15mg/kg)^^^^	Admit
T≥39°C + Well + Non-complete Prevnar (No Prevnar or <4 wks post 1st Prevnar dose)	UA, Urine culture CBC +/- CXR	If WBC(+): Ceftriaxone 50mg-100 mg/kg (also then consider BCx and LP, esp in <6mo old)	Outpatient (24 hour follow-up)
T≥39°C + Well + Prevnar (2 Prevnar or ≥4 wks post 1st Prevnar dose)	Urine workup (UA, UCx) for: Circumcised males <6 months Uncircumcised males <12 months All females +/- CXR	Treat cystitis or PNA if postitive	Outpatient (48hour f/u)
T≥38-38.9°C + Well	Consider UA, CXR based on symptoms, etc	Treat cystitis or PNA if positive	Outpatient (48-72 hour follow-up)

• Consider CXR for:
  • Respiratory symptoms
  • Fever >48 hrs
  • Tachypnea
  • Hypoxia

Work-Up Results

• WBC: 5-15, ANC <10k, <1,500 bands
• UA: (-)Gm Stain, (-) leuks, (-) nitrite, <5-10 wbc/hpf
• CSF: <8wbc, (-) Gm Stain
• When diarrhea present, <5 wbc

If low-risk criteria below not met, LP (if not done) and admit for inpt abx

Managment

• Treat source

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

• Fever
• FUO (Peds)
• UTI (Peds)
• Sepsis (Peds)
• Meningitis (Peds)
• Febrile Seizure

External Links

• PEM ED Algorithm for Pediatric Fever

Source s

• Clinical Policy for Children Younger Than Three Years Presenting to the Emergency Department With Fever. Annuals of Emergency Medicine 2003 42. 530-545
• Risk of Serious Bacterial Infection in Young Febrile Infants With Respiratory Syncytial Virus Infections. Levine et all. PEDIATRICS Vol. 113 No. 6 June 1, 2004 pp. 1728 -1734