105 Neonatal Infections Lori A. Christ Neonates are uniquely susceptible to bacterial and viral infections because of deficiencies in immune function, including neutrophil function and humoral and cellular immunity. Before the introduction of antibiotics, mortality from neonatal sepsis approached 90%; however, even with the advent of antibiotics and identification of common causative organisms, mortality remains 20% to 50%. With continually updated guidelines for maternal screening, the rates of maternally transmitted infections also continue to fall; however, because of significant morbidity, pediatricians must continue to have a high index of suspicion for these infections. Neonatal Sepsis Etiology and Pathogenesis Overall, the incidence of neonatal sepsis is 3 to 4 per 1000 births; it accounts for 25 of 1000 preterm live births. The overall mortality rate is approximately 25%. To aid in identification of likely pathogens, neonatal sepsis is divided into two classifications, early- and late-onset sepsis. Early-onset sepsis represents infection acquired from the maternal genital tract, whether via ascension into the uterus following rupture of membranes or during passage through the vaginal canal during the birth process. As such, it generally presents within the first five to seven days of life with a sudden onset and fulminant course. Ports of entry include the conjunctivae, respiratory tract, umbilicus, skin, and oropharynx. Implicated organisms include group B β-hemolytic streptococci (GBS), Escherichia coli, and less commonly other gram-negative enteric organisms and Listeria monocytogenes. GBS infections account for a large number of cases of early-onset sepsis and have been a focus of Centers for Disease Control and Prevention guidelines because of significant mortality. GBS colonizes the genital tract of 30% of women, and all pregnant women are screened for vaginal and rectal colonization at 35 to 37 weeks of gestation. Colonized women are treated with intrapartum penicillin chemoprophylaxis when delivering vaginally; since the institution of these guidelines, mortality from GBS disease has declined by 80%. Late-onset sepsis may represent organisms acquired from the maternal genital tract but more often are transmitted horizontally by caregivers. Late-onset disease is more common after the first week of life and is more likely to present with urinary tract infection or meningitis caused by hematogenous seeding of end organs. The most common organisms are gram-positive organisms, such as Staphylococcus aureus and GBS, in addition to E. coli and other gram negative organisms. In the community, viral infection should also be included in the differential diagnosis. For hospitalized infants, the most common pathogen is Staphylococcus epidermidis; other organisms to consider include Pseudomonas aeruginosa, Candida spp., anaerobes, and methicillin-resistant S. aureus. Clinical Presentation Neonatal sepsis may present as a constellation of nonspecific symptoms including one or more of the following: progressive lethargy or irritability, apnea, temperature instability, poor feeding, changes in tone, abdominal distension, vomiting or loose stools, or decreased urine output. Fever in a neonate is defined as a temperature of 38.0°C or greater. Clinicians should have a very high index of suspicion for sepsis in an ill-appearing or febrile infant. Evaluation and Management A thorough birth history should be obtained including the following: gestational age (prematurity is the most significant risk factor in the evaluation of neonatal sepsis); duration of rupture of membranes; presence of meconium stained amniotic fluid; indicators of chorioamnionitis, including maternal fever in the peripartum period, fundal tenderness, and foul-smelling amniotic fluid; and invasive procedures such as fetal scalp electrodes. For reasons that are unclear, male infants are four times as likely as female infants to develop early-onset sepsis. The antepartum history is equally as important and should include maternal infections or exposures during pregnancy, the duration of prenatal care, and results of prenatal testing if available. The U.S. Preventative Services Task Force recommends routine screening of mothers for the following: syphilis (rapid plasma reagin [RPR]), hepatitis B (hepatitis B surface antigen [HBsAg]), rubella (titers), HIV, gonorrhea, chlamydia, and GBS. A thorough physical examination should be performed with special attention to the following findings: growth parameters including head circumference, overall appearance of the infant, presence of a bulging fontanel, eye discharge and ophthalmologic examination, nasal discharge, hydration status, respiratory symptoms, perfusion and cardiac examination, abdominal distension, organomegaly, erythema or drainage from the umbilicus, skin lesions including petechiae and vesicles, jaundice, and the overall neurologic examination, including tone. Newborns with historical factors putting them at significant risk for early-onset sepsis should receive serial screening complete blood counts (CBCs) and C-reactive protein levels in the newborn nursery, regardless of their clinical appearance. For infants who are septic appearing in the first days of life, a complete evaluation, including blood culture and lumbar puncture with cerebrospinal fluid (CSF) culture, should be obtained and the infant initiated on appropriate antibiotic coverage until culture results are negative for at least 48 hours. GBS and Listeria coverage with a β-lactam and gram-negative coverage with an aminoglycoside (usually ampicillin and gentamicin) is recommended. Antibiotic therapy may be tailored to cover organisms common to a particular nursery, as indicated. Infants who present after 5 to 7 days of life with any of the symptoms detailed above should be evaluated for late-onset sepsis. Blood, urine, and CSF studies, including cultures before the initiation of antibiotics, should be obtained. Exact laboratory criteria for the diagnosis of late-onset sepsis is somewhat controversial; however, an elevated white blood cell count on an enhanced urinalysis specimen, CSF specimen, or peripheral blood sample is concerning for serious bacterial infection. As in early-onset sepsis, infants should be started on appropriate antibiotics until all culture results are negative. Because meningitis features more prominently in late-onset sepsis, a third-generation cephalosporin (usually cefotaxime) may be substituted for gentamicin if concern for meningitis is high based on clinical examination or lumbar puncture results. Torch Infections Etiology and Pathogenesis The TORCH (toxoplasmosis or Toxoplasma gondii, other infections, rubella, cytomegalovirus [CMV], and herpes simplex virus [HSV]) infections are congenital infections that are transmitted transplacentally from mother to fetus. As a rule, the likelihood of transmission to a fetus is greatest when primary maternal infection occurs. Gestational age at the time of exposure determines the severity of the disease. Neonates who appear most severely infected at birth have most likely been infected during the first trimester; exposure during the first few weeks of gestation may also result in intrauterine demise. TORCH is an acronym that represents the most common pathogens responsible for transplacentally transmitted infections. Historically, these include toxoplasmosis or T. gondii, other infections, rubella, CMV, and HSV. Toxoplasma gondii This is an obligate intracellular protozoan of which cats are the primary host. Maternal infection occurs by ingestion of oocytes via contaminated food or water, and infection persists in the tissues of the human host. Thirty percent of fetuses acquire infection at the time of primary maternal acquisition, resulting in 3500 newly infected infants per year. Other: Syphilis, Hepatitis B, and HIV Neonatal HIV infection occurs transplacentally (≤40% of cases), during delivery, and via breastfeeding postnatally. The risk of transmission increases with high maternal viral load. In the United States, 150 to 300 infants with HIV are born yearly, representing a significant decrease over the past 10 years because of the availability of antiretroviral therapy for pregnant women. Hepatitis B is a DNA-containing hepadnavirus that is transmitted vertically during delivery in almost all cases, and risk is highest with high circulating viral titers. The spirochete Treponema pallidum is the causative agent of syphilis. Rates of primary and secondary syphilis infection continue to decrease within the United States. Maternal factors associated with infection include lack of prenatal care and cocaine use.< div class='tao-gold-member'> Only gold members can continue reading. Log In or Register to continue Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related Related posts: Nutritional Requirements and Growth Polycystic Ovarian Syndrome Constipation Leukemia Stay updated, free articles. Join our Telegram channel Join Tags: Netters Pediatrics Jun 19, 2016 | Posted by admin in PEDIATRICS | Comments Off on Neonatal Infections Full access? Get Clinical Tree
105 Neonatal Infections Lori A. Christ Neonates are uniquely susceptible to bacterial and viral infections because of deficiencies in immune function, including neutrophil function and humoral and cellular immunity. Before the introduction of antibiotics, mortality from neonatal sepsis approached 90%; however, even with the advent of antibiotics and identification of common causative organisms, mortality remains 20% to 50%. With continually updated guidelines for maternal screening, the rates of maternally transmitted infections also continue to fall; however, because of significant morbidity, pediatricians must continue to have a high index of suspicion for these infections. Neonatal Sepsis Etiology and Pathogenesis Overall, the incidence of neonatal sepsis is 3 to 4 per 1000 births; it accounts for 25 of 1000 preterm live births. The overall mortality rate is approximately 25%. To aid in identification of likely pathogens, neonatal sepsis is divided into two classifications, early- and late-onset sepsis. Early-onset sepsis represents infection acquired from the maternal genital tract, whether via ascension into the uterus following rupture of membranes or during passage through the vaginal canal during the birth process. As such, it generally presents within the first five to seven days of life with a sudden onset and fulminant course. Ports of entry include the conjunctivae, respiratory tract, umbilicus, skin, and oropharynx. Implicated organisms include group B β-hemolytic streptococci (GBS), Escherichia coli, and less commonly other gram-negative enteric organisms and Listeria monocytogenes. GBS infections account for a large number of cases of early-onset sepsis and have been a focus of Centers for Disease Control and Prevention guidelines because of significant mortality. GBS colonizes the genital tract of 30% of women, and all pregnant women are screened for vaginal and rectal colonization at 35 to 37 weeks of gestation. Colonized women are treated with intrapartum penicillin chemoprophylaxis when delivering vaginally; since the institution of these guidelines, mortality from GBS disease has declined by 80%. Late-onset sepsis may represent organisms acquired from the maternal genital tract but more often are transmitted horizontally by caregivers. Late-onset disease is more common after the first week of life and is more likely to present with urinary tract infection or meningitis caused by hematogenous seeding of end organs. The most common organisms are gram-positive organisms, such as Staphylococcus aureus and GBS, in addition to E. coli and other gram negative organisms. In the community, viral infection should also be included in the differential diagnosis. For hospitalized infants, the most common pathogen is Staphylococcus epidermidis; other organisms to consider include Pseudomonas aeruginosa, Candida spp., anaerobes, and methicillin-resistant S. aureus. Clinical Presentation Neonatal sepsis may present as a constellation of nonspecific symptoms including one or more of the following: progressive lethargy or irritability, apnea, temperature instability, poor feeding, changes in tone, abdominal distension, vomiting or loose stools, or decreased urine output. Fever in a neonate is defined as a temperature of 38.0°C or greater. Clinicians should have a very high index of suspicion for sepsis in an ill-appearing or febrile infant. Evaluation and Management A thorough birth history should be obtained including the following: gestational age (prematurity is the most significant risk factor in the evaluation of neonatal sepsis); duration of rupture of membranes; presence of meconium stained amniotic fluid; indicators of chorioamnionitis, including maternal fever in the peripartum period, fundal tenderness, and foul-smelling amniotic fluid; and invasive procedures such as fetal scalp electrodes. For reasons that are unclear, male infants are four times as likely as female infants to develop early-onset sepsis. The antepartum history is equally as important and should include maternal infections or exposures during pregnancy, the duration of prenatal care, and results of prenatal testing if available. The U.S. Preventative Services Task Force recommends routine screening of mothers for the following: syphilis (rapid plasma reagin [RPR]), hepatitis B (hepatitis B surface antigen [HBsAg]), rubella (titers), HIV, gonorrhea, chlamydia, and GBS. A thorough physical examination should be performed with special attention to the following findings: growth parameters including head circumference, overall appearance of the infant, presence of a bulging fontanel, eye discharge and ophthalmologic examination, nasal discharge, hydration status, respiratory symptoms, perfusion and cardiac examination, abdominal distension, organomegaly, erythema or drainage from the umbilicus, skin lesions including petechiae and vesicles, jaundice, and the overall neurologic examination, including tone. Newborns with historical factors putting them at significant risk for early-onset sepsis should receive serial screening complete blood counts (CBCs) and C-reactive protein levels in the newborn nursery, regardless of their clinical appearance. For infants who are septic appearing in the first days of life, a complete evaluation, including blood culture and lumbar puncture with cerebrospinal fluid (CSF) culture, should be obtained and the infant initiated on appropriate antibiotic coverage until culture results are negative for at least 48 hours. GBS and Listeria coverage with a β-lactam and gram-negative coverage with an aminoglycoside (usually ampicillin and gentamicin) is recommended. Antibiotic therapy may be tailored to cover organisms common to a particular nursery, as indicated. Infants who present after 5 to 7 days of life with any of the symptoms detailed above should be evaluated for late-onset sepsis. Blood, urine, and CSF studies, including cultures before the initiation of antibiotics, should be obtained. Exact laboratory criteria for the diagnosis of late-onset sepsis is somewhat controversial; however, an elevated white blood cell count on an enhanced urinalysis specimen, CSF specimen, or peripheral blood sample is concerning for serious bacterial infection. As in early-onset sepsis, infants should be started on appropriate antibiotics until all culture results are negative. Because meningitis features more prominently in late-onset sepsis, a third-generation cephalosporin (usually cefotaxime) may be substituted for gentamicin if concern for meningitis is high based on clinical examination or lumbar puncture results. Torch Infections Etiology and Pathogenesis The TORCH (toxoplasmosis or Toxoplasma gondii, other infections, rubella, cytomegalovirus [CMV], and herpes simplex virus [HSV]) infections are congenital infections that are transmitted transplacentally from mother to fetus. As a rule, the likelihood of transmission to a fetus is greatest when primary maternal infection occurs. Gestational age at the time of exposure determines the severity of the disease. Neonates who appear most severely infected at birth have most likely been infected during the first trimester; exposure during the first few weeks of gestation may also result in intrauterine demise. TORCH is an acronym that represents the most common pathogens responsible for transplacentally transmitted infections. Historically, these include toxoplasmosis or T. gondii, other infections, rubella, CMV, and HSV. Toxoplasma gondii This is an obligate intracellular protozoan of which cats are the primary host. Maternal infection occurs by ingestion of oocytes via contaminated food or water, and infection persists in the tissues of the human host. Thirty percent of fetuses acquire infection at the time of primary maternal acquisition, resulting in 3500 newly infected infants per year. Other: Syphilis, Hepatitis B, and HIV Neonatal HIV infection occurs transplacentally (≤40% of cases), during delivery, and via breastfeeding postnatally. The risk of transmission increases with high maternal viral load. In the United States, 150 to 300 infants with HIV are born yearly, representing a significant decrease over the past 10 years because of the availability of antiretroviral therapy for pregnant women. Hepatitis B is a DNA-containing hepadnavirus that is transmitted vertically during delivery in almost all cases, and risk is highest with high circulating viral titers. The spirochete Treponema pallidum is the causative agent of syphilis. Rates of primary and secondary syphilis infection continue to decrease within the United States. Maternal factors associated with infection include lack of prenatal care and cocaine use.< div class='tao-gold-member'> Only gold members can continue reading. Log In or Register to continue Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related Related posts: Nutritional Requirements and Growth Polycystic Ovarian Syndrome Constipation Leukemia Stay updated, free articles. Join our Telegram channel Join Tags: Netters Pediatrics Jun 19, 2016 | Posted by admin in PEDIATRICS | Comments Off on Neonatal Infections Full access? Get Clinical Tree
