Immune System
Specific Nonspecific
MonocytesMacrophagesNeutrophils
Skin and mucous membranesChemical barrierInflammatory responseInterferonPhagocytosis
Cell mediated Humoral
T-lymphocytes Complement B-lymphocytes
AntibodiesDeath of antigenT helperTsuppressorT cytotoxic
Lymphokines
Viral, fungal, protzoan, and some bacterial protectionGraft rejectionSkin hypersensitivityImmune surveillance
IgAViralProtection
IgDFunction unknown
IgEAllergy &ParasiticInfestation
IgGBacterialprotection
IgMBacterial protection
Definition of Neonatal Sepsis
A clinical syndrome of systemic illness accompanied by bacteremia occurring in the first month of life (Gomella,Cunningham and Eyal, 1994)
Pathogenesis of Neonatal Sepsis
Early onset infection: usually multisystem, fulminant illness with prominent respiratory symptoms
Late onset infection: usually has an identifiable focus, most often meningitis, in addition to sepsis
Nosocomial infection: horizontal transmission from NICU environment
Causative Organisms
Primary Sepsis: usually vaginal flora, GBS, gram-negative enteric organisms (E Coli), Listeria monocytogenes, Staphylococcus, Streptococci (including enterococci), anaerobes, and Haemophilus influenzae
Nosocomial Sepsis: Staphylococci (S. Epidermidis and S.Aureus), gram negative rods (Pseudomonas, Klebsiella, Serratia, Proteus) and fungal organisms.
Risk Factors for Sepsis
Maternal Poor PNC and/or nutrition Multiple gestation Low socioeconomic status Recurrent AB Substance abuse Prolonged ROM (>24 hours) Maternal fever/infection Meconium stained or foul-smelling
amniotic fluid Prolonged or difficult labor
Neonatal Prematurity LBW Birth asphyxia Meconium staining Resuscitation Invasive procedures Congenital anomalies (spinal
and abdominal wall defects) Immune defects, asplenia
Clinical Presentation
Thermoregulation Neurologic Skin Gastrointestinal Cardiac Respiratory Metabolic Hematologic
Bacteremia
Thermoregulation
Normal temperature ranges (degrees Celsius)
Skin=36.0-36.5 Rectal=36.5-37.5 Axillary=0.5-1.0 degrees lower
than skin temperature Hypothermia Hyperthermia Temperature instability
Neurologic Symptoms
Lethargy Irritability Decreased muscle
tone Increased muscle
tone Poor feeding Seizures
Hematologic
WBC values
Neutropenia
Thrombocytopenia - Fungal and
G-Negative organisms associated with
lower PLT and more prolonged low PLT
count (Guida, et al 2003 Pediatrics)
Anemia
Disseminated intravascular
coagulation
Cardiac
Tachycardia Bradycardia Hypotension Prolonged capillary
refill Weak peripheral
pulses Cyanosis
Respiratory
Tachypnea Grunting Flaring Retractions Apnea Cyanosis/desaturation Poor air movement Increasing oxygen
requirement
Gastrointestinal
Poor feeding Emesis Gastric residuals Abdominal distention Visible or palpable
bowel loops Diarrhea or bloody
stools
Diagnostic Work-up
CBC with differential Cultures (Blood, Urine,
CSF, tracheal aspirate) X-rays Blood gases Urinalysis PT, PTT, Fibrinogen,
FSP or D-dimer
Bacterial Infection
Blood (Septicemia) CSF (Meningitis) Pneumonia Urinary tract infection Ophthalmia Otitis media Necrotizing enterocolitis
Viral Infection
Rubella Cytomegalovirus (CMV) - Breastmilk main source of perinatally
acquired CMV. More concern in ELBW infants (Yasuda et al, 2003, Pediatrics)
Herpes simplex virus (HSV) Hepatitis B virus Hepatitis C virus AIDS (Human immunodeficiency virus-HIV)
Acronym for Microorganisms Responsible for Infection of the Fetus
(Remington & Klein, 2001) TORCHES To= Toxoplasma gondii R= Rubella virus C= Cytomegalovirus H= Herpes simplex virus E= Enteroviruses S= Syphilis (Treponema
pallidum
CLAP C= Chickenpox (varicella-
zoster virus) L= Lyme disease (Borrelia
burgdorferi) A= AIDS (human
imunodeficiency virus) P= Parvovirus B19
Management of Sepsis
Universal precautions Initial therapy: Broad
spectrum antibiotic coverage
Continuing therapy: Based on culture and sensitivity
Isolation