Recurrent neonatal sepsis and progressive white matter injury in a premature newborn culture-positive for group B Streptococcus: A case report

RATIONALE

Group B Streptococcus (GBS) remains a principal pathogen causing neonatal sepsis and meningitis, particularly in premature infants with relatively insufficient immunity. Recurrence may occur uncommonly, largely associated with subclinical mucosal persistence or repetitive exposure to exogenous sources. White matter injury (WMI) including cystic periventricular leukomalacia (PVL) has been associated with intrauterine infection/inflammation, and neonatal infection as a more significant predictor including postnatal sepsis and recurrent infection, even without microbial neuroinvasion. Furthermore, clinical and experimental evidence of WMI by some bacteria other than GBS without central nervous system invasion has been reported. However, there is little evidence of WMI associated with neonatal GBS sepsis in the absence of meningitis in the literature.

PATIENT CONCERNS

A newborn at 30+4 weeks' gestation with low birthweight presented with 2 episodes (with a 13-day interval with no antibiotic therapy) of neonatal sepsis culture-proven for GBS with early-onset presentation after clinical chorioamnionitis via vertical GBS transmission and the associated conditions including prematurity-related neonatal immunodeficiency and persistent mucosal GBS carriage after the first antibiotic treatment. The perinatal GBS infection was complicated by progressive WMI presenting with ventriculomegaly and cystic PVL without a definite evidence of meningitis, intraventricular hemorrhage, and documented cerebral hypoxia or hypoperfusion conditions including septic shock.

DIAGNOSES

Recurrent group B streptococcal sepsis and cystic PVL with ventriculomegaly.

INTERVENTIONS

Two episodes of GBS sepsis were treated with 15-day parenteral antibiotic therapy, respectively.

OUTCOMES

Resolution of the recurrent GBS sepsis without further relapses, however, complicated by WMI and subsequent about 6 months delay in motor development at 12 months' corrected age.

LESSONS

This case suggests WMI associated with GBS bacteremia without central nervous system entry by viable GBS and also shows that in premature infants, intrauterine GBS infection with no interventions may lead to extensive and persistent GBS colonization, early-onset and recurrent GBS disease, and WMI. Postnatal as well as intrauterine infection/inflammation controls with maternal prophylaxis may be pivotal for prevention and limiting the magnitude of neurologic injury.

Impact of histologic chorioamnionitis on pulmonary hypertension and respiratory outcomes in preterm infants

We aimed to evaluate the association between the presence of histologic chorioamnionitis (HC) and development of pulmonary hypertension (PH) during neonatal intensive care unit (NICU) stay. Data of preterm infants born at 32 weeks of gestation or less were reviewed. The development of PH and other respiratory outcomes were compared according to the presence of HC. Potential risk factors associated with the development of PH during NICU stay were used for multivariable logistic regression analysis. A total of 188 infants were enrolled: 72 in the HC group and 116 in the no HC group. The HC group infants were born at a significantly shorter gestational age and lower birthweight, with a greater proportion presenting preterm premature rupture of membrane (pPROM) > 18 h before delivery. More infants in the HC group developed pneumothorax (P = 0.008), and moderate and severe bronchopulmonary dysplasia (BPD; P = 0.001 and P = 0.006, respectively). PH in the HC group was significantly more frequent compared to the no HC group (25.0% versus 8.6%, P = 0.002). Based on a multivariable logistic regression analysis, birthweight (P = 0.009, odds ratio [OR] = 0.997, 95% confidence interval [CI] = 0.995–0.999), the presence of HC (P = 0.047, OR = 2.799, 95% CI = 1.014–7.731), and duration of invasive mechanical ventilation (MV) > 14 days (P = 0.015, OR = 8.036, 95% CI = 1.051–43.030) were significant factors. The presence of HC and prolonged invasive MV in infants with lower birthweight possibly synergistically act against preterm pulmonary outcomes and leads to the development of PH. Verification of this result and further investigation to establish effective strategies to prevent or ameliorate these adverse outcomes are needed.

Long-term postnatal steroid effect in very low birth weight infants

We examined whether hydrocortisone exposure≤1week in very low birth weight infants (VLBWI) was associated with poor neurodevelopmental outcomes at corrected 18months. Further, the clinical factors associated with worse long term outcome were also evaluated. Of a total of 191 VLBWI, the clinical data for these infants relating were retrospectively collected for analysis. Among the 191 VLBWI, 115 (60.2%) infants were exposed to early postnatal hydrocortisone≤1week of life in our NICU of Seoul St. Mary's Hospital, The Catholic University of Korea between December 2012 and December 2014. The morbidities were significantly higher in the group with early hydrocortisone exposure group. At corrected age of 18months, 109/183 (59.6%) infants in the early hydrocortisone exposure group had significantly lower scores in all three (cognitive, language and motor) composites of Bayley Scales of Infant and Toddler Development III. The multivariable logistic regression analysis showed that only periventricular leukomalacia (PVL) is consistently associated with poor long-term outcomes. Our results suggest that early hydrocortisone exposure≤1week in VLBWI may not increase the risk for poor long-term outcomes compared to those not exposed. Only PVL is considered as a risk factor for poor long-term neurodevelopmental outcomes.

Therapeutic hypothermia in infants with hypoxic-ischemic encephalopathy and reversible persistent pulmonary hypertension: short-term hospital outcomes

AIM

Neonatal hypoxic ischemic encephalopathy (HIE) patients are at times accompanied by persistent pulmonary hypertension (PPHN), which is by itself another risk factor of adverse outcomes. We aimed to assess the outcome of therapeutic hypothermia (TH) in these patients whom we managed to reverse the shunt flow, as they are expected to be at much higher risk of adverse neurodevelopmental outcome.

METHODS

We reviewed the medical records of 116 HIE infants (13 with PPHN and 103 without PPHN) who underwent TH between 2012 and 2016. We analyzed the short-term hospital outcomes and brain study results (electroencephalogram and magnetic resonance imaging) of TH in these patients.

RESULTS

While infants with PPHN were significantly more likely to be outborn or have meconium aspiration syndrome, and required a longer duration of inotrope and intensive care support, electroencephalographic and brain magnetic resonance findings did not significantly differ according to PPHN status.

CONCLUSION

Based on our study, the hospital outcomes of infants with HIE accompanied by reversible PPHN who underwent TH were in general not significantly graver than those not accompanied by PPHN. Our results suggest that undergoing TH may be more beneficial in HIE infants with PPHN and the risks for possible adverse effects may not be as so high.

Timing of surgical ligation and morbidities in very low birth weight infants

The present study examined whether early patent ductus arteriosus (PDA) surgical ligation at ≤2 weeks of life was associated with increased morbidities and mortality in very low birth weight infants (VLBWIs) who were diagnosed with hemodynamically significant (hs) PDA. Between December 2013 and December 2015, a total of 407 VLBWIs were admitted, of whom 145 (35.6%) infants were diagnosed with an hs PDA. The clinical data for these infants were retrospectively collected for analysis. Among the 145 VLBWIs with an hs PDA, 58 (40%) infants had surgical ligation for PDA; of these, 29 (50%) infants had early ligation (EL; ligation at ≤2 weeks of life) and 29 (50%) infants had late ligation (LL; ligation at ≥2 weeks of life). The mean gestational age and birth weight were significantly lower in the PDA-ligated group compared with the nonligated group. In addition, pulmonary hypertension at ≤1 week of life and neonatal seizures were significantly more prevalent in the ligated group (P < 0.05). Increased rate of ROP laser treatment, bronchopulmonary dysplasia, longer hospital stays, and longer duration of mechanical ventilation were found in ligated group (P < 0.05). However, the morbidities and mortality did not differ significantly between the EL and LL groups. Pulmonary hypertension at ≤1 week of life was significantly associated with LL (P = 0.019), which was consistently a risk factor for hs PDA ligation in our multivariable logistic regression analysis. EL was not significantly associated with increased hospital morbidities and mortality in VLBWIs with hs PDA. Pulmonary hypertension at ≤1 week of life can be a risk factor for the need for surgical ligation of hs PDA.

Clinical characteristics predicting abnormal brain magnetic resonance image findings in hypoxic-ischemic encephalopathy infants

BACKGROUND

The aim of this study was to elucidate the specific clinical characteristics associated with abnormal brain magnetic resonance image (MRI) findings in hypoxic ischemic encephalopathy (HIE) infants in order to discern how to predict poorer outcomes more accurately.

METHODS

A retrospective data analysis of HIE infants admitted to the neonatal intensive care unit of a tertiary hospital was performed. Baseline perinatal information and physical and neurological findings were compared in HIE infants according to the presence of abnormal brain MRI findings.

RESULTS

A total of 69 infants were enrolled in the study. Of these, 48(69.6%) infants received therapeutic hypothermia, and 60(87.0%) infants presented abnormal findings on brain MRI. Decreased muscle tone and lower Apgar scores were more often observed in infants with abnormal MRI results(P<0.05). The presence of hypotonia and 1- and 5-minute Apgar scores equal to or less than the yielded cut-off values (5.5 and 7.5, respectively)were associated with a 7.23-, 9.14-, 9.78-fold increased risk of having abnormal brain MRI results.

CONCLUSIONS

As muscle tone and Apgar scores were associated with abnormal brain MRI findings in HIE infants, these clinical characteristics may serve as early indicators of poor neurodevelopmental outcomes and signal the need for special attention and in-depth follow-up by MRI.

Clinical characteristics predicting abnormal brain magnetic resonance image findings in hypoxic-ischemic encephalopathy infants

BACKGROUND

The aim of this study was to elucidate the specific clinical characteristics associated with abnormal brain magnetic resonance image (MRI) findings in hypoxic ischemic encephalopathy (HIE) infants in order to discern how to predict poorer outcomes more accurately.

METHODS

A retrospective data analysis of HIE infants admitted to the neonatal intensive care unit of a tertiary hospital was performed. Baseline perinatal information and physical and neurological findings were compared in HIE infants according to the presence of abnormal brain MRI findings.

RESULTS

A total of 69 infants were enrolled in the study. Of these, 48(69.6%) infants received therapeutic hypothermia, and 60(87.0%) infants presented abnormal findings on brain MRI. Decreased muscle tone and lower Apgar scores were more often observed in infants with abnormal MRI results(P<0.05). The presence of hypotonia and 1- and 5-minute Apgar scores equal to or less than the yielded cut-off values (5.5 and 7.5, respectively)were associated with a 7.23-, 9.14-, 9.78-fold increased risk of having abnormal brain MRI results.

CONCLUSIONS

As muscle tone and Apgar scores were associated with abnormal brain MRI findings in HIE infants, these clinical characteristics may serve as early indicators of poor neurodevelopmental outcomes and signal the need for special attention and in-depth follow-up by MRI.

Expanded criteria for retinopathy of prematurity screening in moderately preterm infants: Single-center pilot study

BACKGROUND

While developed countries seek to lower the gestational age and birthweight parameters in retinopathy of prematurity (ROP) screening, older, larger infants still develop ROP in other parts of the world. The aim of this study was therefore to define criteria to identify potential ROP developers who are outliers of the common screening range.

METHODS

A retrospective medical record review was performed in 147 inborn moderately preterm infants admitted to the neonatal intensive care unit during the study period. Univariate and logistic regression analysis was carried out.

RESULTS

Forty-two infants developed ROP. Gestational age (31.4 ± 1.1 vs 32.4 ± 1.0 weeks, P = 0.000) and birthweight (1607.7 ± 339.4 vs 1846.4 ± 317.2 g, P = 0.000) were lower in those who developed ROP. Respiratory distress syndrome (P = 0.026) and documented sepsis (P = 0.003) were significant comorbidities on univariate analysis. Inotrope need >72 h starting in the first week of life (P = 0.004; OR, 5.181) and more than three transfusions of packed red blood cells (P = 0.028; OR, 3.891) were also significant, both on univariate and multivariate analysis.

CONCLUSIONS

In moderately preterm infants, status should be evaluated in order to effectively select candidates for ROP screening without missing potential ROP developers.

The hospital outcomes compared between the early and late hypothermia-treated groups in neonates

BACKGROUND AND OBJECTIVE

The incidence of hypoxic ischemic encephalopathy (HIE) in developed countries is estimated to be 1.5 per 1000 live births. The primary aim of this study was to analyze whether earlier hypothermia (≤1 h) improves hospital outcomes in survivors who underwent therapeutic hypothermia (TH) when compared with late TH (>1 h).

METHOD

Forty-nine (70%) newborns received TH for 72 h, within 6 h of birth; the remaining 21 received standard care. We divided the TH-treated newborns into early and late groups; early cooling was considered when TH was started ≤1 h after birth; late cooling was considered when started >1 h.

RESULTS

The early TH group consisted of 20 of 49 (41%) infants; the late TH group consisted of 29 (59%) infants. Apgar score at 1 min and the initial calcium level was significantly lower in the early (≤1 h) TH infants; there were significantly more inborns in the early TH group (p = 0.008). Infants in the late TH group manifested more clinical seizures followed by more abnormal EEG findings, longer ventilator care and longer hospitalization (p = 0.001). TH-related complications and mortality were not significantly different between the two groups.

CONCLUSIONS

Early TH (≤1 h) had lower Apgar score at 1 min and initial calcium level, but had decreased incidence of clinico-electrical seizures among HIE infants. Also, ventilator support and hospitalization period were longer in the late TH group.

Risk factor profile of massive pulmonary haemorrhage in neonates: the impact on survival studied in a tertiary care centre

OBJECTIVE

Pulmonary haemorrhage (PH) in neonates is a fatal event leading to hazardous complications and even death. The aim of this study was to elucidate influential factors of the ultimate disease course that affect death or survival.

METHODS

Infants treated for PH in our institution from March 2009 to December 2013 were retrospectively reviewed. Infants transferred from other hospitals were excluded. Infants were grouped into two categories, deceased or survived at neonatal intensive care unit discharge. Information regarding perinatal history, initial management and laboratory results were obtained and analysed for each group.

RESULTS

Seventy infants fulfilled the inclusion criteria, 41 infants in the deceased group and 29 infants in the survived group. Overall, the infants in the deceased group displayed lower gestational age (27 and 1/7 ± 3.610 versus 29 and 3/7 ± 3.530 weeks, p = 0.009) and lower one-minute (2.342 ± 1.493 versus 4.035 ± 2.079, p < 0.001) and five-minute Apgar scores (2.342 ± 1.493 versus 4.035 ± 2.079, p < 0.001) and required aggressive resuscitation (p = 0.003) and a greater number of inotropes (2.195 ± 1.346 versus 1.069 ± 0.704, p < 0.001). Deceased infants were administered increased amounts of fluid during the first 24 h after birth (117.783 ± 32.325 versus 99.379 ± 17.728 mL/kg, p = 0.004). A relatively short prothrombin time impacted survival (p = 0.01), whereas platelet count was the only factor that significantly affected the time length from the onset of PH to death (p = 0.01).

CONCLUSION

Infants with a lower gestational age in a compromised state are prone to die once PH develops. The initial management of fluid intake not to exceed the adequate limit is especially important in order to prevent PH-related deaths when correcting hypoalbuminemia and coagulopathy.

Effects of tert-butyl acetate on maternal toxicity and embryo-fetal development in Sprague-Dawley rats

This study investigated the potential adverse effects of tert-butyl acetate (TBAc) on maternal toxicity and embryo-fetal development after maternal exposure of pregnant rats from gestational days 6 through 19. TBAc was administered to pregnant rats by gavage at 0, 400, 800, and 1,600 mg/kg/day. All dams were subjected to a Caesarean section on day 20 of gestation, and their fetuses were examined for any morphological abnormalities. At 1,600 mg/kg, maternal toxicity manifested as increases in the incidence of clinical signs and death, lower body weight gain and food intake, increases in the weights of adrenal glands and liver, and a decrease in thymus weight. Developmental toxicity included a decrease in fetal weight, an increase in the incidence of skeletal variation, and a delay in fetal ossification. At 800 mg/kg, only a minimal developmental toxicity, including an increase in the incidence of skeletal variation and a delay in fetal ossification, were observed. In contrast, no adverse maternal or developmental effects were observed at 400 mg/kg. These results show that a 14-day repeated oral dose of TBAc is embryotoxic at a maternally toxic dose (i.e., 1,600 mg/kg/day) and is minimally embryotoxic at a nonmaternally toxic dose (i.e., 800 mg/kg/day) in rats. However, no evidence for the teratogenicity of TBAc was noted in rats. It is concluded that the developmental findings observed in the present study are secondary effects to maternal toxicity. Under these experimental conditions, the no-observed-adverse-effect level of TBAc is considered to be 800 mg/kg/day for dams and 400 mg/kg/day for embryo-fetal development.

Evaluation of developmental toxicity of amitraz in Sprague-Dawley rats

This study investigated the potential adverse effects of amitraz on the initiation and maintenance of pregnancy in Sprague-Dawley rats as well as its effects on embryo-fetal development after maternal exposure during the entire pregnancy period. Amitraz was administered to pregnant rats by gavage from days 1 to 19 of gestation at dose levels of 0, 3, 10, and 30 mg/kg/day. All dams underwent a caesarean section on day 20 of gestation and their fetuses were examined for any external, visceral, and skeletal abnormalities. At 30 mg/kg, maternal toxicity manifested as an increase in the incidence of abnormal clinical signs and a lower body weight gain and food intake. Developmental toxicity included an increase in the fetal death rate, a decrease in the litter size, and a reduction in the fetal body weight. In addition, there was an increase in the incidence of fetal external, visceral, and skeletal abnormalities. At 10 mg/kg, maternal toxicity observed included a decrease in the body weight gain and a decrease in food intake. In addition, minimal developmental toxicity, including a decrease in the fetal body weight, an increase in the visceral and skeletal aberrations, and a delay in fetal ossification. There were no signs of either maternal toxicity or developmental toxicity at 3 mg/kg. These results show that amitraz administered during the entire pregnancy period in rats is embryotoxic and teratogenic at the maternally toxic dose (i.e., 30 mg/kg/day) and is minimally embryotoxic at a minimally maternally toxic dose (i.e., 10 mg/kg/day). Under these experimental conditions, the no-observed-adverse-effect level of amitraz for both dams and embryo-fetal development is estimated to be 3 mg/kg/day.

BAPTA/AM, an intracellular calcium chelator, induces delayed necrosis by lipoxygenase-mediated free radicals in mouse cortical cultures

1. Disruption of calcium homeostasis during neurodegenerative diseases is known to trigger apoptotic or necrotic death in neuronal cells. Recently, the authors reported that intracellular calcium restriction by NMDA receptor antagonists induces apoptosis in cortical cultures. To evaluate whether further restriction of intracellular free calcium can induce apoptosis or necrosis, we examined the neurotoxic characterization of BAPTA/AM, a permeable free calcium chelator, in mouse cortical cultures. 2. Exposure of mixed (glia and neuron) cortical cultures (DIV 13-16) to 3-10 microM BAPTA/AM (non-toxic concentration for glial cells) for 24-48 hr resulted in delayed and necrotic neuronal death. The necrotic findings included swelling and loss of mitochondria and endoplasmic reticulum (ER) with neuronal membrane rupture 24 hr after treatment with BAPTA/AM. Simultaneously, we observed a few TUNEL-positive cells in the neuronal subpopulation of the same cultures. 3. The neurotoxicity evoked by BAPTA/AM (10 microM) was significantly attenuated by the addition of 0.5 microM cycloheximide (a protein synthesis inhibitor), 10 microM actinomycin D (an RNA transcription inhibitor), a high extracellular potassium concentration (total 15 mM KCl), 100 microM t-ACPD (a metabotrophic agonist), 100 microM alpha-tocopherol (a free radical scavenger), 100 microM deferoxamine (a ferric ion chelator), 100 microM L-NAME (a nitric oxide synthase (NOS) inhibitor), 50 microM DNQX (a non-NMDA receptor blocker), and 3-30 microM esculetin (a lipoxygenase inhibitor). However, 0.3-3 mM ASA (a cyclooxygenase inhibitor), 100 ng/ml nerve growth factor (NGF), 10 microM MK-801 (a NMDA receptor antagonist), 20 microM zVAD-fmk (caspase inhibitor) and 50 U/ml catalase failed to inhibit the injury. 4. However, NGF and catalase blocked the neurotoxicity induced by BAPTA/AM in young neuronal cells (DIV 6). BAPTA/AM (10 microM) did not alter the expression of inducible nitric oxide synthase (iNOS) on glial cells. 5. These results suggest that the feature of neuronal death induced by BAPTA/AM exhibits predominantly delayed necrosis mediated by lipoxygenase-dependent free radicals.