Links To And Excerpts From SGEM #296 – She’s Got The Fever But Does She Need An LP, Antibiotics, Or Admission

In this post I link to and excerpt from SGEM#296: SHE’S GOT THE FEVER BUT DOES SHE NEED AN LP, ANTIBIOTICS OR AN ADMISSION?
Posted by admin | Jun 20, 2020 from The Skeptic’s Guide To Emergency Medicine.

Note to myself: My blog has many links to excellent FOAM resources on neonatal fever as it is a great concern to all pediatric clinicians (MDs, NPs, and PAs). SGEM #296 is also an outstanding resource on the topic.

A great point in the podcast is to always consider that the fever might be secondary to Herpes Simplex  especially in neonates less than 28 days. And this viral infection will not be treated by an antibiotic.

Always remember that a neonate’s appearance can be deceiving, see:

  • The Yale Observation Scale Score and the Risk of Serious Bacterial 
    Infections in Febrile Infants. 2017.

    • CONCLUSIONS: In this large prospective cohort of febrile infants ≤60 days of age, neither the YOS score nor unstructured clinician suspicion reliably identified those with invasive bacterial infections. More accurate clinical and laboratory predictors are needed to risk stratify febrile infants.
    • What’s Known on This Subject: Most febrile
      infants have viral rather than bacterial infections.
      Clinical scores, such as the Yale Observation Scale
      (YOS) score, have been developed to predict bacterial
      infections in febrile children, however, there is less
      information regarding infants ≤60 days of age.
      What This Study Adds: Many febrile infants ≤60
      days of age with invasive bacterial infections, such as
      bacteremia and bacterial meningitis, had normal YOS
      scores. Neither unstructured clinician suspicion nor
      the YOS reliably identified those febrile infants with
      invasive bacterial infections.

And finally, I find the following to be a good link to a resource on when and when not to perform a pediatric lumbar puncture:

Here are excerpts from the show notes of SGEM#296:

Guest Skeptic: Dr. Dennis Ren is a Pediatric Emergency Medicine fellow at Children’s National Hospital in Washington, DC.

Reference: Kuppermann et al. A Clinical Prediction Rule to Identify Febrile Infants 60 Days and Younger at Low Risk for Serious Bacterial InfectionsJAMA Pediatr. 2019.

CaseA 5-week-old full term female presents to the Emergency Department (ED) for fever with rectal temp of 100.6F (38.1C). Her mother states that she has been fussier today. She also seems “congested” and is not feeding as well. She continues to have the usual number of wet diapers. The mother is worried about her sick baby. She wants to know if they will need a spinal tap, be placed on antibiotics or will need to be admitted to the hospital?

Background: Fever without source in infants less than three months old represents a significant diagnostic dilemma for clinicians. Several criteria have been developed previously, including the Rochester (Jaskiewicz et al 1994), Boston (Baskin et al 1992) and Philadelphia (Baker et al 1993) criteria to help clinicians stratify the risk of serious bacterial infections (SBI).

Febrile infants commonly present to the emergency department. It is estimated 8-13% may have SBI that may include urinary tract infections, bacteremia, and bacterial meningitis. It is difficult to identify which infants have SBI by clinical examination alone. There are serious consequences from missed SBI. Workup for SBI may include lumbar puncture, antibiotics, and hospitalization.

These criteria (Rochester, Boston and Philadelphia) could be considered out of date in our current era of vaccinations. We covered a new protocol called the Step-by-Step approach on SGEM#171. The “Step-by-Step”rule combined both clinical factors and laboratory factors in febrile infants aged 22 to 90 days. It had a sensitivity of 98.9% to detect all SBIs.

The SGEM Bottom Line #171: “If you have availability of serum procalcitonin measurement in a clinically-relevant time frame, the Step-by-Step approach* to fever without source in infants 90 days old or younger is better than using the Rochester criteria or Lab-score methods. With the caveat that you should be careful with infants between 22-28 days old or those who present within two hours of fever onset.”

[*See Step-by-Step Approach to Febrile Infants (Link is to the MDCalc article)]

It is important to balance the consequences of missing an SBI with performing unnecessary procedures (lumbar punctures), exposing infants to antibiotics, and prolonging hospital stay. The new study proposes a novel way of identifying low risk febrile infants 29-60 days based on three objective lab criteria.

[This new clinical prediction rule discussed in SGEM#296 is somewhat different from the Step-By-Step Approach  discussed in SGEM#171 above.]

CLINICAL QUESTION: CAN A CLINICAL PREDICTION RULE (TOOL) USING LABORATORY DATA IDENTIFY FEBRILE INFANTS UNDER 60 DAYS OF AGE WHO ARE AT LOW RISK FOR SERIOUS BACTERIAL INFECTION (URINARY TRACT INFECTION, BACTEREMIA, AND BACTERIAL MENINGITIS) AND REDUCE UNNECESSARY LUMBAR PUNCTURES, ANTIBIOTIC EXPOSURE, AND HOSPITALIZATION?

Reference: Kuppermann et al. A Clinical Prediction Rule to Identify Febrile Infants 60 Days and Younger at Low Risk for Serious Bacterial Infections. [PubMed Abstract]  [Full Text HTML]. . 2019 Apr; 173(4): 342–351.

  • Population: Febrile infants <60 days of age who look good and whose blood cultures were obtained to rule out SBI (fever was a rectal temperature of at least 38C)
    • ExcludedInfants who looked critically ill, had antibiotics in the previous 48 hours, history of prematurity (≤36 weeks’ gestation), pre-existing medical conditions, indwelling devices or soft tissue infections.
  • Intervention: Derivation and validation of accurate clinical prediction rule (tool) for infants at low risk of SBI using a negative urinalysis, ANC <4,090/uL, and procalcitonin 1.71 ng/ml or less.
  • Outcome: Accuracy of the prediction rule to identify infants at low risk for SBI (sensitivity, specificity, negative prediction value and negative likelihood ratio).
    • SBI was defined as bacterial meningitis, bacteremia or UTI.
      • UTI was defined as growth of a single urine pathogen with at least 1,000 cfu/ml on culture obtained by suprapubic aspiration, at least 50,000 cfu/ml from catheterized specimens or 10,000-50,000 cfu/ml from catheterized specimens in association with an abnormal urinalysis (presences of leukocytes esterase, nitrite or pyuria).

Authors’ Conclusions:We derived and validated an accurate prediction rule to identify febrile infants 60 days and younger at low risk for SBIs using the urinalysis, ANC, and procalcitonin levels. Once further validated on an independent cohort, clinical application of the rule has the potential to decrease unnecessary lumbar punctures, antibiotic administration, and hospitalizations.”

Comment on Authors’ Conclusion Compared to SGEM Conclusion: We generally agree with the authors’ conclusions.


SGEM BOTTOM LINE: THIS NEW CLINICAL PREDICTION RULE HAS THE POTENTIAL TO DECREASE UNNECESSARY LUMBAR PUNCTURES, ANTIBIOTIC ADMINISTRATION, AND HOSPITALIZATIONS IN FEBRILE INFANTS 60 DAYS AND YOUNGER AT LOW RISK FOR SERIOUS  BACTERIAL INFECTIONS BUT NEEDS TO BE EXTERNALLY VALIDATED.


Case Resolution: You explain to the mother that given her baby’s age (35 days), she is at risk of SBI. You need to check the blood and urine for signs of infection. Pending the results, you may also need to do an LP. Urine and blood samples are obtained and sent for culture. The urinalysis is unremarkable. The blood tests demonstrate an ANC and procalcitonin below their respective cut offs. The patient has taken a bottle in the ED and is now afebrile with stable vital signs. You do not administer antibiotics or admit the infant to the hospital. You reassure the mother it is OK to go home. She is told to follow up in the next 1-2 days with her pediatrician or return to the ED if she has any concerns.

Clinically Application: This is a well-designed and executed study that offers a novel way of identifying low risk febrile infants age 29-60 days based on objective lab criteria. The clinical prediction rule with three objective lab findings can help identify infants at low risk for SBI and may spare patients the need for lumbar puncture, empiric antibiotics, and hospitalization. I would NOT apply this rule to infants ≤28 days as they have higher risk of infection including HSV which the rule does not account for and the procalcitonin of ≤1.71 ng/mL is cut off when urinalysis and ANC are normal. As a reminder, clinical prediction rules do NOT replace clinical judgement. Prediction rules should help guide clinical judgement not dictate clinical care. Clinical predication tools often have lower diagnostic accuracy and wider confidence intervals when external validation is performed. This tool should be externally validated before recommending its general use.

What Do I Tell My Patient (parents/caregivers)? In babies under the age of 60 days with fever, we always think about the possibility of infection. This could be an infection in the urine, blood, or spinal fluid which coats the brain. I would like to start by testing your infant’s urine and blood for signs of infection. Depending on those results, we may need to perform a lumbar puncture to obtain spinal fluid, give antibiotics, or have your child stay in the hospital. We can talk more after the initial results come back.

Additional Resources:

Link To And Excerpts From Clinical Practice Guidelines On Pediatric Lumbar Puncture From The Royal Children’s Hospital Melbourne
Posted on June 21, 2020 by Tom Wade MD

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