- Email: [email protected]
Increased incidence of sepsis at birth in neutropenic infants of mothers with preeclampsia
Increased incidence of sepsis at birth in neutropenic infants of mothers with preeclampsia Mia W. Doron, MD, Rita A. Makhlouf, MD, Vern L. Katz, MD, Edward E. Lawson, MD, a n d Alan D. Stiles, MD From the Divisionof Neonatal/Perinatal Medicine, Department of Pediatrics, and the Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Universityof North Carolina Hospitals, Universityof North Carolina at Chapel Hill Neutropenia is often found at birth in infants born to mothers with preeclampsia, and is most likely present in utero. To determine whether this neutropenia is associated with an increased incidence of early-onset sepsis, we reviewed the hospital records of 301 low birth weight infants of mothers with preeclampsia. Early-onset sepsis was proved if the result of a culture of blood or cerebrospinal fluid in the first 48 hours of life was positive, or presumed if culture results were n e g a t i v e but two or more clinical signs of sepsis were present and the attending neonatologist b e l i e v e d that an infant was infected and needed at least 7 days of antibiotic therapy. Forty-eight percent of low birth weight infants of mothers with preeclampsia had neutropenia at less than 12 hours of age. Infants with neutropenia had mothers with more severe preeclampsia, were more premature (30 weeks vs 32 weeks), weighed less (1097 gm vs 1615 gm), and were more likely to be small for gestational age. Although maternal and obstetric risk factors for infection were less c o m m o n in the group with neutropenia, rates of proven or presumed early-onset sepsis were higher (14% vs 2%; p <0.001). Sepsis was proved in 6% of infants with neutropenia and in none of the infants without neutropenia (p = 0.03). A logistic regression analysis of the relative effects of birth weight, gestational age, and absolute neutrophil count on the incidence of sepsis revealed that only a low absolute neutrophil count correlated significantly with an increased risk of early-onset sepsis in infants with neutropenia. (J PEDIATR1994;125:452-8)
Neutropenia is present at birth in 40% to 50% of infants born to mothers with preeclampsia 1"4 and is most common in very premature infants. 4, 5 The low neutrophil count usually resolves before 3 days of age 4 and has generally been considered a benign manifestation of maternal disease. Supporting that concept are reports that infants of mothers with preeclampsia do not have an increased incidence of sepsis compared with infants born to normotensive mothSubmitted for publication Dec. 8, 1993; accepted March 22, 1994. Reprint requests: Mia W. Doron, MD, Division of Neonatal/Perinatal Medicine, CB No. 7596, Fourth Floor, UNC Hospitals, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7596. Copyright 9 1994 by Mosby-Year Book, Inc. 0022-3476/94/$3.00 + 0 9/23/56232 452
ers.2, 6 Two recent studies, however, have documented more hospital-acquired infections after 3 days of age in infants with neutropenia who were born to mothers with preANC BP CBC HELLP LBW VLBW
Absolute neutrophil count Blood pressure Complete blood cell count Hemolysis, elevated serum liver enzyme concentrations, and low platelet count [syndrome] Low birth weight Very low birth.weight
eclampsia.4, 7 Whether this neutropenia is also associated with infection acquired around the time of birth is not known. Because low birth weight infants have deficiencies in immune function, 81~ an associated neutropenia could place
Doron et al.
The Journal o f Pediatrics Volume 125, Number 3
them at high risk of becoming infected in the peripartum period. The purpose of this study was to determine whether neutropenia in LBW infants of mothers with preeclampsia is associated with an increased incidence of early-onset sepsis. METHODS Hospital records of a cohort of LBW infants (<2500 gin) born to mothers with preeclampsia at the University of .North Carolina Hospitals between July 1, 1987, and Dec. 31, 1992, were reviewed. Preeclampsia was identified by obstetric discharge diagnosis and confirmed on chart review. For this study, preeclampsia was defined as hypertension (diastolic blood pressure >90 mm Hg, or systolic BP >140 mm Hg, or an increase from baseline BP of -->30 mm Hg systolic or -> 15 mm Hg diastolic) plus proteinuria, edema, elevated serum liver enzyme concentrations, or central nervous system signs and symptoms (headache, blurry vision, or seizures) in a pregnant woman with no other cause for the symptoms. The HELLP syndrome was diagnosed when hemolysis, elevated serum liver enzyme concentrations, and low platelet count were present in addition to signs of preeclampsia. Infants of mothers with preeclampsia were included in the study if they had been admitted to one of our special care nurseries, had had a complete blood cell count and differential cell count before 12 hours of age, and had remained in our hospital for at least 5 days. They were excluded if they had multiple congenital anomalies or if another cause of neutropenia was identified. Infants had blood cultures, CBCs, and differential cell counts if a physician determined that they were clinically indicated. If more than one CBC and differential cell count were obtained in the first 12 hours of life, the earliest sample was used for analysis. The absolute neutrophil counts were performed with a Technicon H2 counter (Miles, Inc., Atlanta, Ga.) and then corrected for the number of nucleated erythrocytes by a hematology laboratory technologist who reviewed the smears. Blood samples were taken from capillaries, arteries, or veins. The ANCs were not adjusted for sample site, because this is not done in clinical practice. We defined neutropenia as an ANC less than 2.2 X 109/L in the first 12 hours of life, the lowest number in the range reported by Lloyd and Otol 1of neutrophil counts in healthy, preterm infants. We did not use the Manroe criteria 1 for neonatal neutropenia because those values were derived from more mature neonates and their applicability to LBW infants has been questioned.5, 7, tH4 For comparison, however, infants from this study were also categorized as having neutropenia or not by the Manroe criteria, to test whether this method of defining neutropenia altered any association with early-onset sepsis.
453
Early-onset sepsis was defined as sepsis that occurred within 48 hours of birth. Proven sepsis was identified if a bacterial pathogen was cultured from either blood or cerebrospinal fluid. Presumed sepsis was defined as the presence of two or more clinical signs of sepsis, with an assessment by the attending neonatologist that a baby was infected and required at least 7 days of antibiotic treatment despite negative culture results. Clinical signs of sepsis accepted for this study were hypotension treated with pressor medications, metabolic acidosis, glucose intolerance, disseminated intravascular coagulation, and increasing ventilatory requirements. Neutropenia and thrombocytopenia were specifically excluded as signs of sepsis, the latter because many infants of mothers with preeclampsia also have low platelet counts.2 Neonatal data collected included race, gender, birth weight, size for gestational age, Apgar scores, endotracheal intubation, the presence of central catheters and other indwelling devices, antibiotic treatment, and date of discharge or death. Gestational age was determined by the obstetric estimate unless the Ballard examination for newborn gestational age differed by >2 weeks, in which case the Ballard estimation was used. Also recorded were maternal and antenatal information, including maternal age and parity, measures of the severity of preeclampsia before delivery (elevated serum liver enzyme concentrations, highest systolic and diastolic BPs, lowest platelet count, HELLP syndrome), maternal treatment with corticosteroids or antibiotics in the week before delivery, rectovaginal culture results for group B streptococcus, chorioanmionitis (diagnosed as maternal fever >38 ~ C and uterine tenderness, fetal tachycardia, purulent amniotic fluid, or positive results of amniotic fluid culture or Gram stain) and other suspected or documented maternal infections within 2 weeks of delivery, time with ruptured membranes, route of delivery, whether internal fetal monitoring was performed, and the umbilical artery pH at delivery. Statistics. Statistical analyses using the chi-square test for categorical variables, with Yates correction when appropriate, and the Student t test for continuous variables were performed with Systat software (Systat, Inc., Evanston, Ill.). Forward stepwise logistic regression was performed on SAS software (SAS Institute, Inc., Cary, N.C.). RESULTS A total of 301 infants with birth weights <2500 grams were born to mothers with preeclampsia at the University of North Carolina Hospitals and admitted to our special care nurseries during the study period; 2t9 met entry criteria and were included in the analysis. Eighty-two infants were excluded: the mothers of 2 infants did not meet our criteria for preeclampsia, the chart of 1 infant was not
454
Doron et al.
The Journal o f Pediatrics September 1994
T a b l e I. Characteristics of infants with neonatal neutropenia
ANC (• Early-onset sepsis Proven only Proven + presumed Death From sepsis From any cause Gestational age (wk) Birth weight (gm) Small for gestational age Apgar score (median) At 1 rain At 5 min Endotracheal intubation Central line in first 48 hr Severity of maternal preeclampsia Highest systolic BP Highest diastolic BP Lowest platelet count Elevated serum liver enzyme concentrations HELLP syndrome Antenatal steroids Antibiotics Antenatal Postnatal Chorioamnionitis Other maternal infection within 2 wk of delivery Duration of ruptured membranes (median hr) Cesarean section Internal fetat monitor
Neutropenia (n = 106)
No n e u t r o p e n i a (n = 113)
p
1.1 _+ 0.6
4.4 _+ 2.3
<0.00i
6 (6%) 15 (14%)
0 (0%) 2 (2%)
4 (4%) 12 (I I%) 30 _+ 3 1095 _+ 325 27 (25%)
1 (1%) I (1%) 32 _+ 2 1615 _+ 420 15 (13%)
NS 0.001 <0.001 <0.001 0.02
5 (1-9) 8 (2-10) 86 (81%) 82 (77%)
7 (1-9) 8 (2-9) 50 (44%) 51 (45%)
<0.001 <0.001
182 +_ 21 113 +_ 12 152 -+ 69 83 (78%) 34 (32%) 62 (58%)
174 + 21 108 + 11 184 _+ 79 68 (61%) 20 (18%) 54 (48%)
0.009 0.07 0.002 0.008 0.0.1 NS
40 (38%) 92 (87%) 3 (3%) 33 (31%) 0 (0-30) 83 (78%) 37 (35%)
37 (33%) 73 (65%) 2 (2%) 32 (28%) 3 (0-259) 64 (57%) 58 (52%)
NS <0.001 NS NS
0.03 0.001
0.001 0.02
ANC, gestational age, birth weight,systolicBP, diastolicBP, and platelet count are expressedas means _+SD. Apgar scoresand duration of ruptured membranes are expressed as medians, with ranges in parentheses. All other categories are shown as n (%). NS, Not significant.
available, 2 infants had multiple congenital anomalies, 47 infants did not have a CBC or differential cell count in the first 12 hours of life, 26 infants were discharged before 5 days of age, and 4 infants had other possible causes of neutropenia (2 underwent exchange transfusion, 1 had congenital syphilis, and 1 had congenital toxoplasmosis). Neutropenia was present in 106 (48%) of these 219 infants in the first 12 hours of life, consistent with the incidence rePorted in other studies. 4' 5, 7 The mean A N C of infants with neutropenia was 1.1 x 109/L, compared with 4.4 • 109/L in the group without neutropenia (p < 0.00i). More severe preeclampsia, indicated by maternal characteristics such as higher systolic and diastolic BPs, lower platelet counts, elevated serum liver enzyme concentrations, and H E L L P syndrome, was associated with a higher incidence of neonatal neutropenia (Table I). Neutropenia was more common in infants who were more premature, weighed less, and were small for gestational age. The neutropenic
and nonneutropenic groups did not differ significantly with regard to race, gender, maternal age, umbilical artery pH, and 5-minute Apgar score. There were also no significant differences in the incidence of chorioamnionitis, maternal infection within 2 weeks of delivery, or antenatal steroid or antibiotic therapy within 1 week of delivery. Two obstetric risk factors for neonatal infection, increased time with ruptured membranes and internal fetal monitoring, were more common in infants without neutropenia. Infants with neutropenia were more likely to be born bY cesarean section. After delivery, infants with neutropenia were more apt to have endotracheal intubation and central catheters, and to receive antibiotics. The mortality rate was higher in the neutropenic group. Blood cultures were obtained in 208 (95%) of the 219 study infants. No infant without a blood culture had clinical signs of sepsis. Proven or presumed early-onset sepsis was diagnosed in 17 neonates, yielding an 8% overall inci-
The Journal o f Pediatrics Volume 125, Number 3
lable
Doron et al.
455
II. Characteristics of infants with early-onset sepsis
ANC (• 109/L) In whole cohort In neutropenic group Death From sepsis From any cause Gestational age (wk) Birth weight (gm) Small for gestational age Apgar score (median) At 1 min At 5 min Endotracheal intubation Central line in first 48 hr Severity of preeclampsia Highest systolic BP Highest diastolic BP Lowest platelet count Elevated serum liver enzyme concentrations HELLP syndrome Antenatal steroids Antibiotics Antenatal Postnatal Chorioamnionitis Other maternal infection within 2 wk of delivery Duration of ruptured membranes (median hr) Cesarean section Internal fetal monitor
Sepsis (n = 17)
No sepsis (n = 202)
p
1.6 • 1.3 1.2 _+ 0.6
2.9 • 2.4 1.1 • 0.6
0.02 NS
5 (29%) 5 (29%) 30 + 3 1235 • 452 2 (12%)
-8 (4%) 31 • 3 1375 _+ 457 40 (20%)
<0.001 NS NS NS
6 (1-8) 8 (2-9) 15 (88%) 12 (71%)
6 (1-9) 8 (2-10) 121 (60%) 121 (60%)
NS NS 0.02 NS
179 • 21 115 + 11 161 + 83 12 (71%) 5 (29%) 11 (65%)
178 • 22 110 _+ 12 169 • 75 139 (69%) 49 (24%) 105 (52%)
NS NS NS NS NS NS
6 (35%) 17 (100%) 3 (18%) 6 (35%) 9 (0-30) 12 (71%) 10 (59%)
71 (35%) 148 (73%) 2 (l%) 59 (29%) 0 (0-259) 135 (67%) 85 (43%)
NS 0.03 <0.001 NS NS NS
ANC, gestational age, birth weight,systolicBP, diastolicBP, and platelet count are expressedas means _+SD. Apgar scoresand duration of ruptured membranes are expressed as medians, with ranges in parentheses. All other categories are shown as n (%). NS, Not significant.
dence of sepsis. Infants with neutropenia were more likely than infants without neutropenia to have early-onset sepsis (14% vs 2%; p <0.001). Sepsis was proved in 6% of the infants with neutropenia and in none of the infants without neutropenia (p = 0.03). The organisms causing sepsis were group B streptococcus and Escherichia coli (three cases each). If the Manroe criteria 1 were used to categorize neutropenia, 20 infants (9%) would be classified differently. Eleven infants would be reclassified as having neutropenia and 9 infants would be reclassified as not having neutropenia. The incidence of proven and presumed early-onset sepsis was higher in neonates who had neutropenia by the Manroe criteria than in infants without neutropenia (13/ 108 [ 12% ] vs 4/111 [4%]; p = 0.02), but the association of neutropenia with proven sepsis alone (5/108 [5%] vs 1/111 [1%]; p = 0.20) was not significant. Because the infants with neutropenia were smaller and younger than the infants without neutropenia, a logistic re-
gression analysis was performed to evaluate the relative effects of birth weight, gestational age, and A N C on the incidence of sepsis. Of these three variables, only a low neutrophil count carried a significant risk of infection (relative risk, 1.6; confidence interval, 1.1 to 2.4). In addition to neutropenia, factors associated with earlyonset sepsis included chorioamnionitis and a longer duration of ruptured membranes (Table II). Gestational age, birth weight, and severity of preeclampsia were not significantly associated with early-onset sepsis in this L B W cohort. Infected infants did not differ from noninfected infants with regard to race, gender, maternal age, or umbilical artery p H at delivery. Infants with sepsis had lower A N C s than infants without sepsis, but within the neutropenic group, the neutrophil count did not differentiate between infants with and those without sepsis. The mortality rate for infants with sepsis was significantly higher than for infants without sepsis (29% vs 4%; p <0.001), and all deaths in the group with sepsis were
456
Doron et al.
attributed to infection. However, infected infants with neutropenia were not more likely to die than infected infants without neutropenia. Although the overall mortality rate was higher in the neutropenic group, the proportion of deaths from sepsis was not significantly greater. DISCUSSION Several investigators have examined whether or not the neonatal neutropenia associated with preeclampsia poses a risk of infection. Koenig and Christensen4 reported that neutropenia was more common in growth-retarded, premature neonates of severely hypertensive mothers, and that these infants had an increased rate of nosocomial infection from 4 to 18 days of life. No attempt was made in that study to separate the effect of prematurity from that of neutropenia on the incidence of infection. Mouzinho et al. 5 confirmed that neutropenia was more prevalent in younger and smaller neonates whose mothers had severe hypertension, but found no higher incidence of nosocomial infection in this group than in infants without neutropenia who were matched by birth weight and age and whose mothers were normotensive. In contrast, Cadnapaphornchai and Faix 7 found that infants with neutropenia whose mothers were hypertensive had more nosocomial infections than infants with neutropenia who were matched by birth weight and whose mothers were normotensive. They concluded that maternal hypertension was an independent risk factor for neonatal infection. These studies did not specifically examine the incidence of early-onset (non-nosocomial) infection in infants born to mothers with preeclampsia. Our study, however, demonstrated that the incidence of early-onset sepsis is higher in infants with neutropenia than in infants with normal neutrophil counts. Although no one has determined whether infants of mothers with preeclampsia have neutropenia in utero, available evidence suggests that this is likely to be the case. Koenig and Christensen4, 15 implicated reduced neutrophil production in neonatal neutropenia associated with pregnancy-induced hypertension, and reported that an inhibitor of neutrophil production is made by the placenta and is present in umbilical cord blood. Their results, together with the findings that more severe preeclampsia is associated with a higher likelihood of neutropenia, and that infants of any gestational age can be born with neutropenia, suggest that a process causes neutropenia before birth. The importance of neutrophil number and function in protecting the fetus from prenatal infection is not known. However, as natural barriers to fetal infection are broken down during labor and delivery, pathogenic organisms may find a more susceptible host in the infant with neutropenia. The organisms cultured from this study population, group B streptococcus and E. coli, are the most common pathogens that
The Journal of Pediatrics September 1994
cause early-onset sepsis in neonates, and their presence is consistent with perinatally acquired infections. An alternative mechanism for the association of a low neutrophil count with early-onset sepsis is depletion of bone marrow neutrophil reserves with infection.16 We cannot exclude the possibility that some of the neutropenia seen in infected infants in this study resulted from sepsis rather than from maternal preeclampsia. However, maternal and obstetric risk factors for infection were less common in infants with neutropenia. Moreover, most cases of neutropenia occurred independent of sepsis, consistent with data showing that sepsis is less frequent than other causes of neutropenia in LBW neonates. 14 In general, premature infants have higher rates of sepsis than term infants. 1719 Although infants in our neutropenic group were younger and smaller than the infants without neutropenia, we cannot attribute their higher incidence of sepsis to a difference in maturity, because infected infants did not differ significantly from noninfected infants with regard to birth weight or gestational age. Furthermore, regression analysis pointed to ANC as the most important predictor of risk for early-onset sepsis. Unfortunately, norms for neutropenia in LBW infants have not been defined. Because the ANC in healthy fetuses rises exponentially during the third trimester of pregnancy, 2~ and because 30% to 70% of very LBW infants have ANCs below Manroe's reference range, 5,7, 11-13,17 it has been suggested that neutropenia may be physiologic in preterm infants. In our cohort, infants with neutropenia were smaller and younger than infants without neutropenia, but the former also had mothers with more severe preeclampsia. We could not separate the effects on neutrophil count of immaturity from those of greater severity of preeclampsia. Mouzinho et al., 5 however, found that more severe preeclampsia was directly associated with neutropenia, indicating that a pathologic process is partly responsible for the low neutrophil counts in these infants. Our definition of neutropenia was chosen to be specific for neutrophil counts below the normal range for LBW neonates; however, it may have encompassed some healthy infants with ANCs appropriate for their g~stational ages. Such an error, if present, would result in a diminished association between neutropenia and sepsis. Birth asphyxia, defined as a 5-minute Apgar score ~<5, has been implicated as a cause of neonatal neutropenia.1 However, Apgar scores as a sign of asphyxia can be misleading in VLBW infants, and we were unable to demonstrate a correlation between neutropenia and 5-minute Apgar score ~ 5 , so we did not exclude these infants. The reported association between intraventricular hemorrhage and neutropenia has been disproved with more accurate diagnostic methods. 1, 13 Similarly, route of delivery and maternal treatment with anti-
The Journal o f Pediatrics Volume 125, Number 3
hypertensive medications or magnesium sulfate have not been reported to cause neutropenia.l, 7 Selection bias that favored the study findings may have occurred if a substantial number of well infants with neutropenia were excluded. This seems unlikely because only 4 (15%) of 26 infants who were discharged from University of North Carolina Hospitals before 5 days of age had neutropenia. They were older (mean gestational age, 34 _+ 2 weeks) and bigger (mean birth weight, 1772 + 350 gm) than the study cohort, and none had proven or presumed sepsis at the time of discharge. Inclusion of this group would have strengthened the association between neutropenia and early-onset sepsis. We cannot know how many infants without a CBC or differential cell count before 12 hours of age had neutropenia; two thirds of them did not have blood cultures drawn. This group was also older and bigger than the study population, and therefore less likely to have neutropenia. However, if a large percentage of these excluded infants had neutropenia and were not infected, a bias that reinforced the study results would have been introduced. We included the category of presumed sepsis because bacterial infection may be present without positive cultures. Neonatal blood cultures have been found to miss up to 33% of infections documented by immediate postmortem cultures. 21-23 Studies of women treated during labor with antibiotics have shown that placental transfer of antibiotics is very efficient and may result in negative results on neonatal blood cultures. 24-26 Infants classified as having presumed sepsis had features more typical of sepsis than of uncomplicated respiratory distress syndrome or other illnesses, as determined by the attending neonatologists. Infants with negative culture results who did not meet our criteria for clinical signs of sepsis, or in whom neutropenia appeared to be a significant factor in the diagnosis of sepsis, were categorized as not infected. Nonetheless, if all infants with presumed sepsis were categorized as not infected, the association between early-onset sepsis and an A N C <2.2 • 109/L in the first 12 hours of life would remain significant. The 29% mortality rate in this cohort is comparable to the 15% to 30% rate reported for neonates with sepsis, 1~ and suggests that therapy after sepsis is diagnosed is often ineffective. Because neutropenia tends to occur in V L B W infants whose mothers have severe preeclampsia, this group of mothers and infants could be targeted for changes in management. If, as we have speculated, neutropenia is present in utero and predisposes infants to early-onset sepsis, treatments that decrease the likelihood of acquiring infection in the peripartum period, or that decrease the incidence of neutropenia before birth or in the immediate newborn period, could be beneficial.
Doron et al.
457
We thank Keith Muller and Richard Sidley, of the General Clinical Research Center, and Dr. Wayne Price, for their help with statistical analysis. Dr. Stiles is a Jefferson Pilot Fellow in Academic Medicine. REFERENCES
1. Manroe BL, Weinberg AG, Rosenfeld CR, Browne R. The neonatal blood count in health and disease. I. Reference values for neutrophilic cells. J PEOIATg 1979;95:89-98. 2. Brazy JE, Grimm JK, Little VA. Neonatal manifestations of severe maternal hypertension occurring before the thirty-sixth week of pregnancy. J PEDIATR 1982;100:265-71. 3. Engle WD, Rosenfeld CR. Neutropenia in high-risk neonates. J PEDIATR 1984;105:982-6. 4. Koenig JM, Christensen RD. Incidence, neutrophil kinetics, and natural history of neonatal neutropenia associated with maternal hypertension. N Engl J Med 1989;321:557-62. 5. Mouzinho A, Rosenfeld CR, Sanchez PJ, Risser R. Effect of maternal hypertension on neonatal neutropenia and risk of nosoeomial infection. Pediatrics 1992;90:430-5. 6. Szymonowicz W, Yu VYH. Severe preeclampsia and infants of very low birth weight. Arch Dis Child 1987;62:712-6. 7. Cadnapaphornchai M, Faix RG. Increased nosocomial infection in neutropenic low birth weight (2000 grams or less) infants of hypertensive mothers. J PEDIATR 1992;121:956-61. 8. Berger M. Complement deficiency and neutrophil dysfunction as risk factors for bacterial infection in newborns and the role of granuloeyte transfusion in therapy. Rev Infect Dis 1990; 12:$401-9. 9. Hill HR. Intravenous immunoglobulin use in the neonate: role in prophylaxis and therapy of infection. Pediatr Infect Dis J 1993;12:549-59. 10. Gerdes JS. Clinicopathologic approach to the diagnosis of neonatal sepsis. Clin Perinatol 1991;18:361-81. 11. Lloyd BW, Oto A. Normal values for mature and immature neutrophils in very preterm babies. Arch Dis Child 1982;57: 233-5. 12. Coulombel L, Dehan M, Tchernia G, Hill C, Vial M. The number of polymorphonuclear leukocytes in relation to gestational age in the newborn. Acta Paediatr Scand 1979;68:70911. 13. Faix RG, Hric J J, Naglie RA. Neutropenia and intraventricular hemorrhage among very low birth weight (less than 1500 grams) premature infants. J PEDIATR 1989;114:1035-8. 14. Baley JE, Stork EK, Warkentin PI, Shurin SB. Neonatal neutropenia. Am J Dis Child 1988;142:1161-6. 15. Koenig JM, Christensen RD. The mechanism responsible for diminished neutrophil production in neonates delivered of women with pregnancy-induced hypertension. Am J Obstet Gynecol 1991;165:467-73. 16. Christensen RD, Rothstein G. Exhaustion of mature marrow neutrophils in neonates with sepsis. J PEDIATR1980;96:316-8. 17. Boyer KM, Gadzala CA, Burd LI, Fisher DE, Paton JB, Gotoff SP. Selective intrapartum chemoprophylaxis of neonatal group B streptococcal early-onset disease. I. Epidemiologic rationale. J Infect Dis 1983;148:795-801. 18. St. Geme JW, Murray DL, Carter J, et al. Perinatal bacterial infection after prolonged rupture of amniotic membranes: an analysis of risk and management. J PEDIATR1984;104:608-13. 19. Gladstone IM, Ehrenkranz RA, Edberg SC, Baltimore RS. A ten-year review of neonatal sepsis and comparison with the
458
20.
21.
22.
23.
Rush et. al.
previous fifty-year experience. Pediatr Infect Dis J 1990;9:81925. Davies NP, Buggins AGS, Snijders RJM, Jenkins E, Layton DM, Nicolaides KH. Blood leucocyte count in the human fetus. Arch Dis Child 1992;67:399-403. Eisenfeld L, Ermocilla R, Wirtschafter D, Cassady G. Systemic bacterial infections in neonatal deaths. Am J Dis Child 1983;137:645-9. Squire E, Favara B, Todd J. Diagnosis of neonatal bacterial infection: hematologic and pathologic findings in fatal and nonfatal cases. Pediatrics 1979;64:60-4. Pierc e JR, Merenstein GB, Stocker JT. Immediate postmor-
The Journal of Pediatrics September 1994
tern cultures in an intensive care nursery. Pediatr Infect Dis 1984;3:510-3. 24. Bray RE, Boe RW, Johnson WL. Transfer of ampicillin into fetus and amniotic fluid from maternal plasma in late pregnancy. Am J Obstet Gynecol 1966;96:938-42. 25. Kraybill EN, Chancy NE, McCarthy LR. Transplacental ampicillin: inhibitory concentrations in neonatal serum. Am J Obstet Gynecol 1980;138:793-6. 26. Boyer KM, Gotoff SP. Prevention of early-onset neonatal group B streptococcal disease with selectiveintrapartum chemoprophylaxis. N Engl J Med 1986;314:1665-9.
Clinical and laboratory observations Intramuscular versus enteral vitamin A supplementation in very low birth weight neonates M a r g a r e t G. Rush, MD, J a y a n t P. Shenai, MD, Robert A. Parker, DSc, a n d Frank Chytil, PhD From the Departments of Pediatrics, Biochemistry, and Preventive Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee We conducted a randomized trial in very low birth weight neonates (n = 51) to determine whether vitamin A supplementation by enteral administration would increase plasma vitamin A concentrations to the same d e g r e e as by intramuscular administration. Mean plasma vitamin A concentrations were significantly higher in the intramuscular-administration group than in the enteral-administration group by postnatal d a y 7; this effect persisted throughout the remainder of the trial. At the dosage used in this trial, vitamin A supplementation by the enteral route is not as effective as that by the intramuscular route in very low birth weight neonates. (J PEDIATR1994;125:458-62)
Vitamin A (retinol) is necessary for the maintenance of normal epithelial cell differentiation. Vitamin A deficiency results in a predictable sequence of pathologic changes in pulmonary conducting airway epithelium cttaracterized by Supported by the Parker B. Francis Foundation (MGR) and by the National Institutes of Health (grant HL14214). Submitted for publication Sept. 29, 1993; accepted March 29, 1994. Reprint requests: Margaret G. Rush, MD, Department of Pediatrics, Vanderbilt University School of Medicine, S-0101 MCN, Nashville, TN 37232-2370. Copyright 9 1994 by Mosby-Year Book, Inc. 0022-3476/94/$3.00 + 0 9/24/56328
early appearance of necrotizing tracheobronchitis and later development of squamous metaplasia. 1, 2 Similar changes have been observed in infants with bronchopulmonary dysplasia. 3 As reviewed by Shenai et al., 4 most very low birth weight neonates are born with low plasma concentrations and hepatic stores of vitamin A; infants in whom BPD develops often manifest clinical, biochemical, and histopathologic evidence of vitamin A deficiency. 5, 6 W e previously showed that vitamin A supplementation (2000 I U on alternate days for 28 days) from early postnatal life in V L B W neonates improves vitamin A status biochemically and also reduces the morbidity associated with BPD. 7 In V L B W neonates at risk of having BPD at our institution, intramus-
Neutropenia is present at birth in 40% to 50% of infants born to mothers with preeclampsia 1"4 and is most common in very premature infants. 4, 5 The low neutrophil count usually resolves before 3 days of age 4 and has generally been considered a benign manifestation of maternal disease. Supporting that concept are reports that infants of mothers with preeclampsia do not have an increased incidence of sepsis compared with infants born to normotensive mothSubmitted for publication Dec. 8, 1993; accepted March 22, 1994. Reprint requests: Mia W. Doron, MD, Division of Neonatal/Perinatal Medicine, CB No. 7596, Fourth Floor, UNC Hospitals, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7596. Copyright 9 1994 by Mosby-Year Book, Inc. 0022-3476/94/$3.00 + 0 9/23/56232 452
ers.2, 6 Two recent studies, however, have documented more hospital-acquired infections after 3 days of age in infants with neutropenia who were born to mothers with preANC BP CBC HELLP LBW VLBW
Absolute neutrophil count Blood pressure Complete blood cell count Hemolysis, elevated serum liver enzyme concentrations, and low platelet count [syndrome] Low birth weight Very low birth.weight
eclampsia.4, 7 Whether this neutropenia is also associated with infection acquired around the time of birth is not known. Because low birth weight infants have deficiencies in immune function, 81~ an associated neutropenia could place
Doron et al.
The Journal o f Pediatrics Volume 125, Number 3
them at high risk of becoming infected in the peripartum period. The purpose of this study was to determine whether neutropenia in LBW infants of mothers with preeclampsia is associated with an increased incidence of early-onset sepsis. METHODS Hospital records of a cohort of LBW infants (<2500 gin) born to mothers with preeclampsia at the University of .North Carolina Hospitals between July 1, 1987, and Dec. 31, 1992, were reviewed. Preeclampsia was identified by obstetric discharge diagnosis and confirmed on chart review. For this study, preeclampsia was defined as hypertension (diastolic blood pressure >90 mm Hg, or systolic BP >140 mm Hg, or an increase from baseline BP of -->30 mm Hg systolic or -> 15 mm Hg diastolic) plus proteinuria, edema, elevated serum liver enzyme concentrations, or central nervous system signs and symptoms (headache, blurry vision, or seizures) in a pregnant woman with no other cause for the symptoms. The HELLP syndrome was diagnosed when hemolysis, elevated serum liver enzyme concentrations, and low platelet count were present in addition to signs of preeclampsia. Infants of mothers with preeclampsia were included in the study if they had been admitted to one of our special care nurseries, had had a complete blood cell count and differential cell count before 12 hours of age, and had remained in our hospital for at least 5 days. They were excluded if they had multiple congenital anomalies or if another cause of neutropenia was identified. Infants had blood cultures, CBCs, and differential cell counts if a physician determined that they were clinically indicated. If more than one CBC and differential cell count were obtained in the first 12 hours of life, the earliest sample was used for analysis. The absolute neutrophil counts were performed with a Technicon H2 counter (Miles, Inc., Atlanta, Ga.) and then corrected for the number of nucleated erythrocytes by a hematology laboratory technologist who reviewed the smears. Blood samples were taken from capillaries, arteries, or veins. The ANCs were not adjusted for sample site, because this is not done in clinical practice. We defined neutropenia as an ANC less than 2.2 X 109/L in the first 12 hours of life, the lowest number in the range reported by Lloyd and Otol 1of neutrophil counts in healthy, preterm infants. We did not use the Manroe criteria 1 for neonatal neutropenia because those values were derived from more mature neonates and their applicability to LBW infants has been questioned.5, 7, tH4 For comparison, however, infants from this study were also categorized as having neutropenia or not by the Manroe criteria, to test whether this method of defining neutropenia altered any association with early-onset sepsis.
453
Early-onset sepsis was defined as sepsis that occurred within 48 hours of birth. Proven sepsis was identified if a bacterial pathogen was cultured from either blood or cerebrospinal fluid. Presumed sepsis was defined as the presence of two or more clinical signs of sepsis, with an assessment by the attending neonatologist that a baby was infected and required at least 7 days of antibiotic treatment despite negative culture results. Clinical signs of sepsis accepted for this study were hypotension treated with pressor medications, metabolic acidosis, glucose intolerance, disseminated intravascular coagulation, and increasing ventilatory requirements. Neutropenia and thrombocytopenia were specifically excluded as signs of sepsis, the latter because many infants of mothers with preeclampsia also have low platelet counts.2 Neonatal data collected included race, gender, birth weight, size for gestational age, Apgar scores, endotracheal intubation, the presence of central catheters and other indwelling devices, antibiotic treatment, and date of discharge or death. Gestational age was determined by the obstetric estimate unless the Ballard examination for newborn gestational age differed by >2 weeks, in which case the Ballard estimation was used. Also recorded were maternal and antenatal information, including maternal age and parity, measures of the severity of preeclampsia before delivery (elevated serum liver enzyme concentrations, highest systolic and diastolic BPs, lowest platelet count, HELLP syndrome), maternal treatment with corticosteroids or antibiotics in the week before delivery, rectovaginal culture results for group B streptococcus, chorioanmionitis (diagnosed as maternal fever >38 ~ C and uterine tenderness, fetal tachycardia, purulent amniotic fluid, or positive results of amniotic fluid culture or Gram stain) and other suspected or documented maternal infections within 2 weeks of delivery, time with ruptured membranes, route of delivery, whether internal fetal monitoring was performed, and the umbilical artery pH at delivery. Statistics. Statistical analyses using the chi-square test for categorical variables, with Yates correction when appropriate, and the Student t test for continuous variables were performed with Systat software (Systat, Inc., Evanston, Ill.). Forward stepwise logistic regression was performed on SAS software (SAS Institute, Inc., Cary, N.C.). RESULTS A total of 301 infants with birth weights <2500 grams were born to mothers with preeclampsia at the University of North Carolina Hospitals and admitted to our special care nurseries during the study period; 2t9 met entry criteria and were included in the analysis. Eighty-two infants were excluded: the mothers of 2 infants did not meet our criteria for preeclampsia, the chart of 1 infant was not
454
Doron et al.
The Journal o f Pediatrics September 1994
T a b l e I. Characteristics of infants with neonatal neutropenia
ANC (• Early-onset sepsis Proven only Proven + presumed Death From sepsis From any cause Gestational age (wk) Birth weight (gm) Small for gestational age Apgar score (median) At 1 rain At 5 min Endotracheal intubation Central line in first 48 hr Severity of maternal preeclampsia Highest systolic BP Highest diastolic BP Lowest platelet count Elevated serum liver enzyme concentrations HELLP syndrome Antenatal steroids Antibiotics Antenatal Postnatal Chorioamnionitis Other maternal infection within 2 wk of delivery Duration of ruptured membranes (median hr) Cesarean section Internal fetat monitor
Neutropenia (n = 106)
No n e u t r o p e n i a (n = 113)
p
1.1 _+ 0.6
4.4 _+ 2.3
<0.00i
6 (6%) 15 (14%)
0 (0%) 2 (2%)
4 (4%) 12 (I I%) 30 _+ 3 1095 _+ 325 27 (25%)
1 (1%) I (1%) 32 _+ 2 1615 _+ 420 15 (13%)
NS 0.001 <0.001 <0.001 0.02
5 (1-9) 8 (2-10) 86 (81%) 82 (77%)
7 (1-9) 8 (2-9) 50 (44%) 51 (45%)
<0.001 <0.001
182 +_ 21 113 +_ 12 152 -+ 69 83 (78%) 34 (32%) 62 (58%)
174 + 21 108 + 11 184 _+ 79 68 (61%) 20 (18%) 54 (48%)
0.009 0.07 0.002 0.008 0.0.1 NS
40 (38%) 92 (87%) 3 (3%) 33 (31%) 0 (0-30) 83 (78%) 37 (35%)
37 (33%) 73 (65%) 2 (2%) 32 (28%) 3 (0-259) 64 (57%) 58 (52%)
NS <0.001 NS NS
0.03 0.001
0.001 0.02
ANC, gestational age, birth weight,systolicBP, diastolicBP, and platelet count are expressedas means _+SD. Apgar scoresand duration of ruptured membranes are expressed as medians, with ranges in parentheses. All other categories are shown as n (%). NS, Not significant.
available, 2 infants had multiple congenital anomalies, 47 infants did not have a CBC or differential cell count in the first 12 hours of life, 26 infants were discharged before 5 days of age, and 4 infants had other possible causes of neutropenia (2 underwent exchange transfusion, 1 had congenital syphilis, and 1 had congenital toxoplasmosis). Neutropenia was present in 106 (48%) of these 219 infants in the first 12 hours of life, consistent with the incidence rePorted in other studies. 4' 5, 7 The mean A N C of infants with neutropenia was 1.1 x 109/L, compared with 4.4 • 109/L in the group without neutropenia (p < 0.00i). More severe preeclampsia, indicated by maternal characteristics such as higher systolic and diastolic BPs, lower platelet counts, elevated serum liver enzyme concentrations, and H E L L P syndrome, was associated with a higher incidence of neonatal neutropenia (Table I). Neutropenia was more common in infants who were more premature, weighed less, and were small for gestational age. The neutropenic
and nonneutropenic groups did not differ significantly with regard to race, gender, maternal age, umbilical artery pH, and 5-minute Apgar score. There were also no significant differences in the incidence of chorioamnionitis, maternal infection within 2 weeks of delivery, or antenatal steroid or antibiotic therapy within 1 week of delivery. Two obstetric risk factors for neonatal infection, increased time with ruptured membranes and internal fetal monitoring, were more common in infants without neutropenia. Infants with neutropenia were more likely to be born bY cesarean section. After delivery, infants with neutropenia were more apt to have endotracheal intubation and central catheters, and to receive antibiotics. The mortality rate was higher in the neutropenic group. Blood cultures were obtained in 208 (95%) of the 219 study infants. No infant without a blood culture had clinical signs of sepsis. Proven or presumed early-onset sepsis was diagnosed in 17 neonates, yielding an 8% overall inci-
The Journal o f Pediatrics Volume 125, Number 3
lable
Doron et al.
455
II. Characteristics of infants with early-onset sepsis
ANC (• 109/L) In whole cohort In neutropenic group Death From sepsis From any cause Gestational age (wk) Birth weight (gm) Small for gestational age Apgar score (median) At 1 min At 5 min Endotracheal intubation Central line in first 48 hr Severity of preeclampsia Highest systolic BP Highest diastolic BP Lowest platelet count Elevated serum liver enzyme concentrations HELLP syndrome Antenatal steroids Antibiotics Antenatal Postnatal Chorioamnionitis Other maternal infection within 2 wk of delivery Duration of ruptured membranes (median hr) Cesarean section Internal fetal monitor
Sepsis (n = 17)
No sepsis (n = 202)
p
1.6 • 1.3 1.2 _+ 0.6
2.9 • 2.4 1.1 • 0.6
0.02 NS
5 (29%) 5 (29%) 30 + 3 1235 • 452 2 (12%)
-8 (4%) 31 • 3 1375 _+ 457 40 (20%)
<0.001 NS NS NS
6 (1-8) 8 (2-9) 15 (88%) 12 (71%)
6 (1-9) 8 (2-10) 121 (60%) 121 (60%)
NS NS 0.02 NS
179 • 21 115 + 11 161 + 83 12 (71%) 5 (29%) 11 (65%)
178 • 22 110 _+ 12 169 • 75 139 (69%) 49 (24%) 105 (52%)
NS NS NS NS NS NS
6 (35%) 17 (100%) 3 (18%) 6 (35%) 9 (0-30) 12 (71%) 10 (59%)
71 (35%) 148 (73%) 2 (l%) 59 (29%) 0 (0-259) 135 (67%) 85 (43%)
NS 0.03 <0.001 NS NS NS
ANC, gestational age, birth weight,systolicBP, diastolicBP, and platelet count are expressedas means _+SD. Apgar scoresand duration of ruptured membranes are expressed as medians, with ranges in parentheses. All other categories are shown as n (%). NS, Not significant.
dence of sepsis. Infants with neutropenia were more likely than infants without neutropenia to have early-onset sepsis (14% vs 2%; p <0.001). Sepsis was proved in 6% of the infants with neutropenia and in none of the infants without neutropenia (p = 0.03). The organisms causing sepsis were group B streptococcus and Escherichia coli (three cases each). If the Manroe criteria 1 were used to categorize neutropenia, 20 infants (9%) would be classified differently. Eleven infants would be reclassified as having neutropenia and 9 infants would be reclassified as not having neutropenia. The incidence of proven and presumed early-onset sepsis was higher in neonates who had neutropenia by the Manroe criteria than in infants without neutropenia (13/ 108 [ 12% ] vs 4/111 [4%]; p = 0.02), but the association of neutropenia with proven sepsis alone (5/108 [5%] vs 1/111 [1%]; p = 0.20) was not significant. Because the infants with neutropenia were smaller and younger than the infants without neutropenia, a logistic re-
gression analysis was performed to evaluate the relative effects of birth weight, gestational age, and A N C on the incidence of sepsis. Of these three variables, only a low neutrophil count carried a significant risk of infection (relative risk, 1.6; confidence interval, 1.1 to 2.4). In addition to neutropenia, factors associated with earlyonset sepsis included chorioamnionitis and a longer duration of ruptured membranes (Table II). Gestational age, birth weight, and severity of preeclampsia were not significantly associated with early-onset sepsis in this L B W cohort. Infected infants did not differ from noninfected infants with regard to race, gender, maternal age, or umbilical artery p H at delivery. Infants with sepsis had lower A N C s than infants without sepsis, but within the neutropenic group, the neutrophil count did not differentiate between infants with and those without sepsis. The mortality rate for infants with sepsis was significantly higher than for infants without sepsis (29% vs 4%; p <0.001), and all deaths in the group with sepsis were
456
Doron et al.
attributed to infection. However, infected infants with neutropenia were not more likely to die than infected infants without neutropenia. Although the overall mortality rate was higher in the neutropenic group, the proportion of deaths from sepsis was not significantly greater. DISCUSSION Several investigators have examined whether or not the neonatal neutropenia associated with preeclampsia poses a risk of infection. Koenig and Christensen4 reported that neutropenia was more common in growth-retarded, premature neonates of severely hypertensive mothers, and that these infants had an increased rate of nosocomial infection from 4 to 18 days of life. No attempt was made in that study to separate the effect of prematurity from that of neutropenia on the incidence of infection. Mouzinho et al. 5 confirmed that neutropenia was more prevalent in younger and smaller neonates whose mothers had severe hypertension, but found no higher incidence of nosocomial infection in this group than in infants without neutropenia who were matched by birth weight and age and whose mothers were normotensive. In contrast, Cadnapaphornchai and Faix 7 found that infants with neutropenia whose mothers were hypertensive had more nosocomial infections than infants with neutropenia who were matched by birth weight and whose mothers were normotensive. They concluded that maternal hypertension was an independent risk factor for neonatal infection. These studies did not specifically examine the incidence of early-onset (non-nosocomial) infection in infants born to mothers with preeclampsia. Our study, however, demonstrated that the incidence of early-onset sepsis is higher in infants with neutropenia than in infants with normal neutrophil counts. Although no one has determined whether infants of mothers with preeclampsia have neutropenia in utero, available evidence suggests that this is likely to be the case. Koenig and Christensen4, 15 implicated reduced neutrophil production in neonatal neutropenia associated with pregnancy-induced hypertension, and reported that an inhibitor of neutrophil production is made by the placenta and is present in umbilical cord blood. Their results, together with the findings that more severe preeclampsia is associated with a higher likelihood of neutropenia, and that infants of any gestational age can be born with neutropenia, suggest that a process causes neutropenia before birth. The importance of neutrophil number and function in protecting the fetus from prenatal infection is not known. However, as natural barriers to fetal infection are broken down during labor and delivery, pathogenic organisms may find a more susceptible host in the infant with neutropenia. The organisms cultured from this study population, group B streptococcus and E. coli, are the most common pathogens that
The Journal of Pediatrics September 1994
cause early-onset sepsis in neonates, and their presence is consistent with perinatally acquired infections. An alternative mechanism for the association of a low neutrophil count with early-onset sepsis is depletion of bone marrow neutrophil reserves with infection.16 We cannot exclude the possibility that some of the neutropenia seen in infected infants in this study resulted from sepsis rather than from maternal preeclampsia. However, maternal and obstetric risk factors for infection were less common in infants with neutropenia. Moreover, most cases of neutropenia occurred independent of sepsis, consistent with data showing that sepsis is less frequent than other causes of neutropenia in LBW neonates. 14 In general, premature infants have higher rates of sepsis than term infants. 1719 Although infants in our neutropenic group were younger and smaller than the infants without neutropenia, we cannot attribute their higher incidence of sepsis to a difference in maturity, because infected infants did not differ significantly from noninfected infants with regard to birth weight or gestational age. Furthermore, regression analysis pointed to ANC as the most important predictor of risk for early-onset sepsis. Unfortunately, norms for neutropenia in LBW infants have not been defined. Because the ANC in healthy fetuses rises exponentially during the third trimester of pregnancy, 2~ and because 30% to 70% of very LBW infants have ANCs below Manroe's reference range, 5,7, 11-13,17 it has been suggested that neutropenia may be physiologic in preterm infants. In our cohort, infants with neutropenia were smaller and younger than infants without neutropenia, but the former also had mothers with more severe preeclampsia. We could not separate the effects on neutrophil count of immaturity from those of greater severity of preeclampsia. Mouzinho et al., 5 however, found that more severe preeclampsia was directly associated with neutropenia, indicating that a pathologic process is partly responsible for the low neutrophil counts in these infants. Our definition of neutropenia was chosen to be specific for neutrophil counts below the normal range for LBW neonates; however, it may have encompassed some healthy infants with ANCs appropriate for their g~stational ages. Such an error, if present, would result in a diminished association between neutropenia and sepsis. Birth asphyxia, defined as a 5-minute Apgar score ~<5, has been implicated as a cause of neonatal neutropenia.1 However, Apgar scores as a sign of asphyxia can be misleading in VLBW infants, and we were unable to demonstrate a correlation between neutropenia and 5-minute Apgar score ~ 5 , so we did not exclude these infants. The reported association between intraventricular hemorrhage and neutropenia has been disproved with more accurate diagnostic methods. 1, 13 Similarly, route of delivery and maternal treatment with anti-
The Journal o f Pediatrics Volume 125, Number 3
hypertensive medications or magnesium sulfate have not been reported to cause neutropenia.l, 7 Selection bias that favored the study findings may have occurred if a substantial number of well infants with neutropenia were excluded. This seems unlikely because only 4 (15%) of 26 infants who were discharged from University of North Carolina Hospitals before 5 days of age had neutropenia. They were older (mean gestational age, 34 _+ 2 weeks) and bigger (mean birth weight, 1772 + 350 gm) than the study cohort, and none had proven or presumed sepsis at the time of discharge. Inclusion of this group would have strengthened the association between neutropenia and early-onset sepsis. We cannot know how many infants without a CBC or differential cell count before 12 hours of age had neutropenia; two thirds of them did not have blood cultures drawn. This group was also older and bigger than the study population, and therefore less likely to have neutropenia. However, if a large percentage of these excluded infants had neutropenia and were not infected, a bias that reinforced the study results would have been introduced. We included the category of presumed sepsis because bacterial infection may be present without positive cultures. Neonatal blood cultures have been found to miss up to 33% of infections documented by immediate postmortem cultures. 21-23 Studies of women treated during labor with antibiotics have shown that placental transfer of antibiotics is very efficient and may result in negative results on neonatal blood cultures. 24-26 Infants classified as having presumed sepsis had features more typical of sepsis than of uncomplicated respiratory distress syndrome or other illnesses, as determined by the attending neonatologists. Infants with negative culture results who did not meet our criteria for clinical signs of sepsis, or in whom neutropenia appeared to be a significant factor in the diagnosis of sepsis, were categorized as not infected. Nonetheless, if all infants with presumed sepsis were categorized as not infected, the association between early-onset sepsis and an A N C <2.2 • 109/L in the first 12 hours of life would remain significant. The 29% mortality rate in this cohort is comparable to the 15% to 30% rate reported for neonates with sepsis, 1~ and suggests that therapy after sepsis is diagnosed is often ineffective. Because neutropenia tends to occur in V L B W infants whose mothers have severe preeclampsia, this group of mothers and infants could be targeted for changes in management. If, as we have speculated, neutropenia is present in utero and predisposes infants to early-onset sepsis, treatments that decrease the likelihood of acquiring infection in the peripartum period, or that decrease the incidence of neutropenia before birth or in the immediate newborn period, could be beneficial.
Doron et al.
457
We thank Keith Muller and Richard Sidley, of the General Clinical Research Center, and Dr. Wayne Price, for their help with statistical analysis. Dr. Stiles is a Jefferson Pilot Fellow in Academic Medicine. REFERENCES
1. Manroe BL, Weinberg AG, Rosenfeld CR, Browne R. The neonatal blood count in health and disease. I. Reference values for neutrophilic cells. J PEOIATg 1979;95:89-98. 2. Brazy JE, Grimm JK, Little VA. Neonatal manifestations of severe maternal hypertension occurring before the thirty-sixth week of pregnancy. J PEDIATR 1982;100:265-71. 3. Engle WD, Rosenfeld CR. Neutropenia in high-risk neonates. J PEDIATR 1984;105:982-6. 4. Koenig JM, Christensen RD. Incidence, neutrophil kinetics, and natural history of neonatal neutropenia associated with maternal hypertension. N Engl J Med 1989;321:557-62. 5. Mouzinho A, Rosenfeld CR, Sanchez PJ, Risser R. Effect of maternal hypertension on neonatal neutropenia and risk of nosoeomial infection. Pediatrics 1992;90:430-5. 6. Szymonowicz W, Yu VYH. Severe preeclampsia and infants of very low birth weight. Arch Dis Child 1987;62:712-6. 7. Cadnapaphornchai M, Faix RG. Increased nosocomial infection in neutropenic low birth weight (2000 grams or less) infants of hypertensive mothers. J PEDIATR 1992;121:956-61. 8. Berger M. Complement deficiency and neutrophil dysfunction as risk factors for bacterial infection in newborns and the role of granuloeyte transfusion in therapy. Rev Infect Dis 1990; 12:$401-9. 9. Hill HR. Intravenous immunoglobulin use in the neonate: role in prophylaxis and therapy of infection. Pediatr Infect Dis J 1993;12:549-59. 10. Gerdes JS. Clinicopathologic approach to the diagnosis of neonatal sepsis. Clin Perinatol 1991;18:361-81. 11. Lloyd BW, Oto A. Normal values for mature and immature neutrophils in very preterm babies. Arch Dis Child 1982;57: 233-5. 12. Coulombel L, Dehan M, Tchernia G, Hill C, Vial M. The number of polymorphonuclear leukocytes in relation to gestational age in the newborn. Acta Paediatr Scand 1979;68:70911. 13. Faix RG, Hric J J, Naglie RA. Neutropenia and intraventricular hemorrhage among very low birth weight (less than 1500 grams) premature infants. J PEDIATR 1989;114:1035-8. 14. Baley JE, Stork EK, Warkentin PI, Shurin SB. Neonatal neutropenia. Am J Dis Child 1988;142:1161-6. 15. Koenig JM, Christensen RD. The mechanism responsible for diminished neutrophil production in neonates delivered of women with pregnancy-induced hypertension. Am J Obstet Gynecol 1991;165:467-73. 16. Christensen RD, Rothstein G. Exhaustion of mature marrow neutrophils in neonates with sepsis. J PEDIATR1980;96:316-8. 17. Boyer KM, Gadzala CA, Burd LI, Fisher DE, Paton JB, Gotoff SP. Selective intrapartum chemoprophylaxis of neonatal group B streptococcal early-onset disease. I. Epidemiologic rationale. J Infect Dis 1983;148:795-801. 18. St. Geme JW, Murray DL, Carter J, et al. Perinatal bacterial infection after prolonged rupture of amniotic membranes: an analysis of risk and management. J PEDIATR1984;104:608-13. 19. Gladstone IM, Ehrenkranz RA, Edberg SC, Baltimore RS. A ten-year review of neonatal sepsis and comparison with the
458
20.
21.
22.
23.
Rush et. al.
previous fifty-year experience. Pediatr Infect Dis J 1990;9:81925. Davies NP, Buggins AGS, Snijders RJM, Jenkins E, Layton DM, Nicolaides KH. Blood leucocyte count in the human fetus. Arch Dis Child 1992;67:399-403. Eisenfeld L, Ermocilla R, Wirtschafter D, Cassady G. Systemic bacterial infections in neonatal deaths. Am J Dis Child 1983;137:645-9. Squire E, Favara B, Todd J. Diagnosis of neonatal bacterial infection: hematologic and pathologic findings in fatal and nonfatal cases. Pediatrics 1979;64:60-4. Pierc e JR, Merenstein GB, Stocker JT. Immediate postmor-
The Journal of Pediatrics September 1994
tern cultures in an intensive care nursery. Pediatr Infect Dis 1984;3:510-3. 24. Bray RE, Boe RW, Johnson WL. Transfer of ampicillin into fetus and amniotic fluid from maternal plasma in late pregnancy. Am J Obstet Gynecol 1966;96:938-42. 25. Kraybill EN, Chancy NE, McCarthy LR. Transplacental ampicillin: inhibitory concentrations in neonatal serum. Am J Obstet Gynecol 1980;138:793-6. 26. Boyer KM, Gotoff SP. Prevention of early-onset neonatal group B streptococcal disease with selectiveintrapartum chemoprophylaxis. N Engl J Med 1986;314:1665-9.
Clinical and laboratory observations Intramuscular versus enteral vitamin A supplementation in very low birth weight neonates M a r g a r e t G. Rush, MD, J a y a n t P. Shenai, MD, Robert A. Parker, DSc, a n d Frank Chytil, PhD From the Departments of Pediatrics, Biochemistry, and Preventive Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee We conducted a randomized trial in very low birth weight neonates (n = 51) to determine whether vitamin A supplementation by enteral administration would increase plasma vitamin A concentrations to the same d e g r e e as by intramuscular administration. Mean plasma vitamin A concentrations were significantly higher in the intramuscular-administration group than in the enteral-administration group by postnatal d a y 7; this effect persisted throughout the remainder of the trial. At the dosage used in this trial, vitamin A supplementation by the enteral route is not as effective as that by the intramuscular route in very low birth weight neonates. (J PEDIATR1994;125:458-62)
Vitamin A (retinol) is necessary for the maintenance of normal epithelial cell differentiation. Vitamin A deficiency results in a predictable sequence of pathologic changes in pulmonary conducting airway epithelium cttaracterized by Supported by the Parker B. Francis Foundation (MGR) and by the National Institutes of Health (grant HL14214). Submitted for publication Sept. 29, 1993; accepted March 29, 1994. Reprint requests: Margaret G. Rush, MD, Department of Pediatrics, Vanderbilt University School of Medicine, S-0101 MCN, Nashville, TN 37232-2370. Copyright 9 1994 by Mosby-Year Book, Inc. 0022-3476/94/$3.00 + 0 9/24/56328
early appearance of necrotizing tracheobronchitis and later development of squamous metaplasia. 1, 2 Similar changes have been observed in infants with bronchopulmonary dysplasia. 3 As reviewed by Shenai et al., 4 most very low birth weight neonates are born with low plasma concentrations and hepatic stores of vitamin A; infants in whom BPD develops often manifest clinical, biochemical, and histopathologic evidence of vitamin A deficiency. 5, 6 W e previously showed that vitamin A supplementation (2000 I U on alternate days for 28 days) from early postnatal life in V L B W neonates improves vitamin A status biochemically and also reduces the morbidity associated with BPD. 7 In V L B W neonates at risk of having BPD at our institution, intramus-