Infant < 28 days: Do everything & give empiric Abx (Ceftazidime, Acyclovir (HSV) & Ampicillin) ^
CBC, BMP, Blood Cx (1 set), UA, Urine Cx, LP, RVP*
^There are new guidelines regarding patients who are between 3-4 weeks of age where LP may be deferred. There is a lot of controversy still regarding its adoption.
28 days to 2 months / 1st set of vaccines: Do everything however LP & Abx dependent on PECARN Rule for Low Risk Fever
CBC, BMP, Blood Cx (1 set), UA, Urine Cx, RVP*, Pro-Calcitonin
PECARN Rule for Low Risk Fever: LP if any of the following is positive: Pro-Cal > 0.5, ANC > 4090/micoL, Positive UA (due to seeding of CNS). PECARN Rule for Low Risk Fever was done in full term infants without chronic medical problems, no prolonged NICU stay - use discretion in patients with multiple risk factors.
If performing LP, the patient will need abx (Ceftriaxone 100mg/kg) coverage pending CSF studies.
2 months - 4 months / 2nd set of vaccines: Partial Sepsis. No LP unless clinical signs of meningitis due to blood brain barrier
CBC, BMP, Blood Cx (1 set), UA, Urine Cx, RVP*.
Can consider one dose of IV ceftriaxone (75mg/kg) if WBC > 15k, WBC < 5k, or Band to Neutrophil Ratio greater than 0.2. The evidence is not very robust and practice varies.
4 months - 6 months / 3rd set of vaccines: Urine
UA, Urine Cx, RVP*
6 months - 12 months: Urine collection requirement varies
Females: UA, Ucx, RVP*
Circumcised males- No urine, RVP*
Uncircumcised males- Urine if fever > 48 hrs , RVP*
1- 2 years of age: Urine collection in females
Female: UA, UCx, RVP*
Males: No urine, RVP*
*RVP can be useful for finding a source of fever (calming parent anxiety, limiting atypical Kawasaki workup etc...). However, remember patients can have more than one concomitant source of illness and a positive RVP should not prevent one from finishing the appropriate workup in each age group.