to understand the risk factors and common complications

7/31/2019 To Understand the Risk Factors and Common Complications

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Infection and sepsis


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Host Defence Mechanism The incidence of sepsis is approximately 1:1000 in term

infants and 1:250 in preterm infants.

This increased susceptibility in preterm infants relatesto at least three factors:

Diminished maternally transferred antibodies

Immature neonatal immune system Increased risk of nosocomial infections due to a

complicated clinical course and prolongedhospitalization.


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Transplacental Maternal Antibody Transplacental maternal antibodies may protect

against certain infections in neonates, such as GBSinfection. A lack of type-specific maternal antibodiesis associated with an increased risk of GBS sepsis.

Furthermore, active transplacental transport of

maternal antibodies to the fetus occurs predominantlyafter 32 weeks of gestation.


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Pre-Term Immunity Serum IgG levels in preterm infants born prior to 32

weeks are usually 2-4 times lower than those of terminfants.

The defence mechanism in neonates are moreimportant than maternal immunity

Nenonates have a lower level of serum complementand phagocytic activities appear to be less effective ,particularly during stress (eg. Sepsis, surgery)


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Pre-Term Immunity Cell-mediated immunity in preterm and newborn

infants is also believed to be less well-developed thanolder infants.

Preterm infants have fewer capillaries in all theirtissues than term infants, and consequently, their

mobilization of natural defences may be poorer.

Inflammatory responses in immature hosts are alsodeficient.


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Pre-Term ImmunityYoung and adult rabbits have been shown to have

different capacities to develop and localizeinflammation at the site of injection of pneumococci.

In adult rabbits, a very extensive localinflammationdevelops and bacteremia occurs only in relatively few

rabbits.


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Textbook of Neonatal Medicine:A Chinese PerspectiveHong Kong University Press, 1996 - 912 pages

In contrast, young rabbits fail to develop extensivelocal inf lammation and consequently die withbacteremia.

Local reactions in these young rabbits were variable(51% had no reaction, 36% had local redness only and

13% had redness and swelling).

Human newborns react similarly.

Pre-Term Immunity


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Risk factors of Infection and Sepsis Any stage

Prematurity Neutropenia due to other cause

Early onset Sepsis Maternal GBS carrier Maternal HVS positive PROM >18 hours PPROM Chorioamnionitis

Late Onset Sepsis Overcrowded nursery Inadequate hand washing Central lines Infection from family members or contacts.

to understand the risk factors and common complications

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