Neonatal Sepsis

Author: Sherrill Roskam RNC MN NNP CNSUpdated presentation: Susan Greenleaf RNC, BSN

Objectives

Identify major causative organisms and routes of transmission of sepsis.

Discuss clinical manifestations and modalities used in diagnosis of sepsis.

Describe antibiotic therapy used in the treatment of neonatal sepsis.

Sepsis

Definition: A systemic response to an invasive organism. Frequently signified by a positive blood culture.A systemic illness due to the presence of bacteria and or bacterial toxins in the blood

Neonatal Immune System

Sepsis occurs in 1-8:1000 term infants and 1:250 premature infantsNeonates are immunocompromised even at term gestationThe neonatal immune system is functional at birth, but not mature

Sepsis

Two types of sepsisEarly-onset sepsis, with in the first 72 hours of lifeLate-onset sepsis, those infections acquired later by horizontal transmission. Highest risk for the first month of life

Predisposing Factors: Pregnancy

PrematurityPROM < 36 weeksProlonged ROMProlonged laborExcessive manipulation

Predisposing Factors: Maternal

History of infectionBacterialViral

History of GBS bacteriuriaHistory of previously affected infantTemperature in labor

Predisposing Factors: Neonatal

Invasive proceduresResuscitationIntubationIV starts / PICC linesUmbilical Catheterization

Skin colonization

Predisposing Factors: Nursery

HumidifiersRespiratory therapy equipmentStaff membersUnsterile equipment

ScalesStethoscopesThermometers

Transmission

TransplacentalAscendingBirthNosocomialAntibodies

IgGIgMIgA

Human Immunoglobulins

Antibodies are the immunoglobulins produced in response to specific antigensIgG is the only antibody that crosses the placenta and provides immuological protection over the first few months Transfer peaks at 32 weeks gestation

Immunoglobulins cont.

IgM and IgA are directly responsible for antibodies against bacteriaNeonatal IgM production starts at 30 weeks gestation and increases over the first year of lifeIgA passes through breast milk to provide early defense against infection. Found in the intestinal tract.

Causative Organisms:Bacterial

Group B strepE ColiHaemophilus InfluenzaeCoagulase Negative StaphStaph AureusNeisseria MeningitisListeria

Causative Organisms: Viral Maternal in origin

ToxoplasmosisRubellaCytomegalovirusHerpesHepatitis BHIV

Recognition: Clinical Signs

Temperature instabilityLethargyPallor, mottling, poor cap refillRespiratory distressPoor feedingApneaNeurologicJaundiceHypoglycemia

Recognition

Recognition is of utmost importance, because newborns with sepsis can get very sick very fastBe aware of risk factors – review maternal history

Diagnostic tests for sepsis

CBCCultures

Blood ~ Most common Gold StandardUrineSurface - only indicates colonization

CSF Lumbar punctureCRP

C-Reactive Protein

What is CRP?Laboratory test that identifies an inflammatory response in the body.

Binds to Calcium and phosphocholine sites; forming CRP-ligand complexes.

CRP

CRP’s unique binding characteristics have led to the identification of elevated CRP levels in over 70 different infectious and noninfectious disorders.It is associated with acute and chronic inflammatory disorders.

CRP Continued. . .

Paired mother and infant sampling shows that CRP does not cross the placenta.

4 types of inflammatory response to tissue injury

Infectious, noninfectious, chemical, physical or immunologic toxins.

Use of CRP

2 schools of thought

Early diagnostic tool for confirming sepsisScreening tool to r/o the presence of sepsis

CRP Levels: What is normal?

In the neonatal period: Level of 10mg/L is considered normal

Healthy full-term and preterm infants may range from 2 to 5mg/L during the first few days of life.

More than 1 Level?

Conflicting information about obtaining more than one level

Serial CRP levels drawn 12 to 24 hours after onset of S/S of sepsis may be superior to a single level.

More About the CBC: WBC

White cell countDifferential

Neutrophils - bacteria fighting cellsPolys, Segs - most matureBands - immatureMetas – really immature

Absolute Neutrophil CountI:T Ratio

White Blood Cells

The main defense against invading microorganismsNeutrophils (pack man cells) and macrophages(monocytes)

Circulating cells that migrate to sites of inflamation, ingesting and killing foreign material or bacteria (phagocytosis)Small stores in neonates, not as effective in killing bacteria, quickly depleted

Differential of the WBC

Mature Neutrophils – SegmentedImmature Neutrophils – BandsMonocytesBasophilsEosinophilsLymphocytes

Neutrophils

As mature neutrophols (polys, segs, neuts, or PMNs) are mobilized and consumed in the presence of a pathogen, their numbers decrease and immature cells are released from the bone marrow.Immature neutrophils (bands, metas or stabs)

Absolute Neutrophil Count (ANC)

Helps determine how many neutrophils are available to fight bacterial infectionsPremature infants have lower ANC than term infantsMust plot on the Manroe chart

How to calculate an ANC

Identify the immature and the mature neutrophils on the CBC.Add the segs, bands and metas ( total number of neutrophils) together and turn it into a percentageMultiply this number by the total WBC This resulting number is the ANC

Manroe Chart

WBC: 20,000Differential is expressed as a percent of

total white cellsPoly’s (Segs, Neuts): 48%Bands 12%Lymphs: 20%Monos: 17%Eso: 3%

ANC: Absolute number of neutrophils WBC X % Neutrophils

ANC WBC X % Neutrophils20,000 X .6 (60%) = 12,000

Manroe Chart

Immature to Total Ratio (I:T)

An Increased IT ratio is called a left shift. It show an increase in the number of immature sellsAn IT ratio of >.25 may indicate sepsis

I/T ratio: Ratio of immature to total neutrophils

___Bands + Meta___ Polys + Bands + Meta

WBC: 20,000Differential is expressed as a percent of

total white cellsPoly’s (Segs, Neuts): 48%Bands 12%Lymphs: 20%Monos: 17%Eso: 3%

I/T ratio: Bands + Metas Polys + Bands + Metas12/60=0.2 (not indicative of sepsis)

If WBC 3000 Polys 30 and Bands 15: 15/45=0.33 (indicative of sepsis)3,000 X .45 (45%) = 1,350

Platelet Count

Normal Values

VLBW – 275,000 +/- 60,000Preterm – 290,000 +/- 60,000Term – 310,000 +/- 60,000

Infants with infection may have a low platelet count

Management

Support SystemsNeutral Thermal EnvironmentMonitor

Cardiac/RespiratoryPulse Oximetry

Vital signsFeedingsIV

Management (con’t)

AntibioticsAmpicillin 50-100 mg/kg/dose IV q8-12 hours

Varies with gestation and age

Gentamicin 4 mg/kg/dose IV q24-48 hoursVaries with gestationGive over 30 minutesMonitor Gent levels

AntiviralAcyclovir 20 mg/kg/dose IV q8

Give over 1 hourDo not refrigerate

Prognosis

Prognosis depends on organism involved and when treatment started

A bit more practice

CBC resultsWBC 10.4Metamyelocytes 0Band Neutrophils 14Segmented neutrophils 5Platelets 141,000

What is the ANC and the IT ratio?

CBC Practice

CBC resultsWBC 1.3Metamyelocytes 2Band Neutrohils 17Segmented Neutrophils 42Platelets 262,000

Calculate the ANC and IT ratio

CBC Practice

CBC resultsWBC 6.3Metamyelocytes 6Band Neutrophils 44Segmented Neutrophils 23Platelets 95,000

What is the ANC and the IT ratio?

Same patient, 6 hours later

CBC resultsWBC 0.8Metamyelocytes 2Band Neutrophils 4Segmented Neutrophils 2Platelets 24,000

What is the ANC and IT ratio?

References

Behrman, R. E., Kliegman, R.M.,Editors (1998) Nelson Essentials of Pediatrics, 3rd Ed. Philadelphia: W.B. Saunders Co.

Cloherty, J.P., Eichenwald, E.C., Stark, A.R. (2004) Manual of Neonatal Care, 5th Ed. Philadelphia: Lippincott, Williams & Wilkins.

Hengst, J.M., The Role of C-Reactive Protein in the Evaluation and Management of Infants with Suspected Sepsis. Advances in Neonatal Care. 2003;3(1):3-13.

References

Karlsen, K.A. (2001) The S.TA.B.L.E. Program: Transporting Newborns the S.T.A.B.L.E.Way, Learner Manual, 8th Ed.

Merenstein, G.B., Gardner, S.L. (2002) Handbook of Neonatal Intensive Care, 5th Ed. St. Louis:Mosby Inc.