One of the most important factors driving the medical workup on a well appearing, febrile infant is the prevalence of serious bacterial infection (SBI) . This number changes depending on age and immunization status (pneumococcus vaccine having the most impact in North America.) The higher the likelihood of disease, the more aggressive the workup and treatment.
Prevalence of serious bacterial infection/meningitis by age
- 0-14 days (pre-vaccine) 1/10
- 14-28 days 1/20
- 28-60 days (pre-vaccine) 1/100
- 28-60 days (post-vaccine) 1/1,000
- 60-90 days 1/1,000-1/10,000
- >90 days 1/>10,000
Pediatric Fever Trivia
Many parents will bring their febrile infant to the emergency department because the fever is not responding to antipyretics. Does response to antipyretics make SBI less likely?
No. This has been extensively studied and no relationship has been found between response to antipyretics and severity of illness or presence of bacteremia.
Should a chest X-ray be ordered on a febrile child < 3 months of age without respiratory symptoms?
The data to date would suggest no. The likelihood of finding an infiltrate on CXR is extremely low in the absence of ANY of the following exam findings:
- tachypnea > 50 bpm
- nasal flaring
- coryza (runny nose)
If you see even one of these criteria in a febrile infant or neonate, it’s a mandatory CXR, although I still find runny nose a bit of a hard sell indicating a lower respiratory tract infection. Caveat: a child >3 months with a WBC >20,000 should get a CXR to evaluate for occult pneumonia (even if asymptomatic)
What age groups of children are at higher risk for urinary tract infection?
0-6 months circumcised males
0-12 months uncircumcised males
0-24 months females
The term fever without a source implies that a child looks well yet still has a fever. When we want to say that a fever is caused by something we can identify on clinical presentation, what are the recognized/acceptable sources?
- Herpangina/Ulcerative Stomatits
- Viral Exanthum (rash)
- Enterovirus, coxsackie HFM dz, echovirus, rhinovirus, enterovirusIn the emergency department, it’s virtually impossible to identify the exact type of virus causing an upper respiratory infection or gastroenteritis. A little sniffle or drop of mucous from one nostril doesn’t stop the workup, but a copious river of rhinorrhea and a hacking cough in a febrile 3 month old seal the deal.
It all comes down to what tests to order and what treatment to give for the different age groups. The following age based guidelines are based on Dr. Sloas’ approach to the febrile infant as laid out in the podcast. If you disagree with any of this, send us a note or leave a comment on our google voice line. There’s nothing like a feud over pediatric fever.
Reference ABNORMAL values in the febrile infant
- WBC<5 or >15, Band/neutrophil >0.2, Bandemia >1,500 mm3, absolute neutrophil count of >10,000
- CSF > 8 WBC or positive gram stain
- UA > 10 WBC or positive gram stain
- Stool WBCs or heme
- Infiltrate on CXR
Age 0-28 days
Temp > 100.4 or 38C
CBC, blood cx, cath UA, CXR (I still do it), lumbar puncture, stool studies if needed
Disposition: Automatic admission and antibiotics
Ampicillin 50mg/kg plus
Gentamicin – Dose varies by age. Give if child is under 9 days old or
Cefotaxime – 50mg/kg. Give if child is 9-28 days.
Possible add ons
Acyclovir 60mg/kg/day divided q8hrs
The below presume that the child is well appearing, is on the recommended vaccination schedule and does not have an identifiable source of infection
Age 29-60 days
temp >100.4 F or 38C
cbc, blood cx, cath UA, possible CXR, spinal tap, stool studies if needed
Admit for anything positive in workup, unable to get follow-up
50mg/kg ceftriaxone or
If Workup completely negative, no antibiotics and next day follow-up
Age 60-90 days
If the temp is <39C, no testing and followup the next day
Temp >102.2F or 39C
Start with CBC and UA
If both CBC and UA are normal, no antibiotics. Have patient follow-up next day.
If either the CBC or UA are abnormal then proceed with LP and blood culture. And then…
If just the CBC is abnormal, give 50mg/kg ceftriaxone and follow-up next day
If UA is abnormal, give 50mg/kg ceftriaxone, and prior to discharge, initiate oral antibiotics for urinary pathogens (E. coli is the main player) cefixime orTMP/Sulfa. There are many other antibiotic choices for oral agents. The best choice often depends on resistance patterns in your region.
There is wide variability in philosophy regarding LP with an abnormal CBC or UA in the 60-90 day age group. Many community ED docs and pediatricians will send blood culture after an abnormal CBC/UA but do not subscribe to the idea that all patients in this cohort need a spinal tap.
Age 3-6 months
Temp >102.2F or 39C
Treat if positive