Proton magnetic resonance spectroscopic images in preterm infants with bilirubin encephalopathy

The added value of brain MR spectroscopy in children with Crigler-Najjar syndrome type-I: correlation with demographic, neurodevelopmental, and laboratory findings

OBJECTIVE

The aim of this study is to demonstrate the role of proton magnetic resonance spectroscopy (1H-MRS) in the detection of brain microstructural changes in patients with Crigler-Najjar syndrome type-I (CNs-I), and its correlation with demographic, neurodevelopmental and laboratory findings.

METHODS

Prospective study was conducted on 25 children with CNs-I and 25 age and sex-matched children, who served as control. They underwent multivoxel 1H-MRS of basal ganglion at echo time 135-144 ms. N-acetyl aspartate/Creatine (NAA/Cr) and Choline (Ch)/Cr were calculated and correlated with demographic, clinical, and laboratory findings of patients with CNs-I.

RESULTS

There was a significant difference in NAA/Cr and Ch/Cr between patients and controls. The cut-off value for NAA/Cr and Ch/Cr used to differentiate patients from controls were 1.8 and 1.2 with an area under the curve (AUC) of 0.91 and 0.84 respectively. There was a significant difference in MRS ratios between patients with neurodevelopmental delay (NDD) and patients without NDD. The cut-off values for NAA/Cr and Ch/Cr used to differentiate between patients with NDD and patients without NDD were 1.47 and 0.99, with AUC of 0.87 and 0.8 respectively. The NAA/Cr and Ch/Cr were well correlated with family history (p = 0.006 and p < 0.001) respectively, consanguinity (p < 0.001 and p = 0.001), neurodevelopmental delay (p = 0.001 and p = 0.004), serum bilirubin level (r = -0.77, p < 0.001), (r = -0.49, p = 0.014), phototherapy (p < 0.001 and p = 0.32), blood transfusion (p < 0.001 and p = 0.001) respectively.

CONCLUSION

1H-MRS can be a useful tool in the detection of neurological changes in patients with CNs-I; NAA/Cr and Ch/Cr parameters are well correlated with demographic, clinical, and laboratory findings.

ADVANCES IN KNOWLEDGE

Our study is the first report on using MRS in assessing neurological manifestations in CNs. 1H-MRS can be a useful tool in the detection of neurological changes in patients with CNs-I.

A nationwide survey of bilirubin encephalopathy in preterm infants in Japan

OBJECTIVES

To examine the clinical characteristics of bilirubin encephalopathy in preterm infants (pBE) in Japan.

METHODS

We performed a two-step nationwide questionnaire survey. The initial survey determined the number of children with pBE. Using a structured questionnaire, the second survey clarified the clinical manifestations and characteristics of children with pBE, including the perinatal history, neonatal complications, neurological features, verbal communication, diet, and magnetic resonance imaging (MRI) and auditory brainstem response (ABR) findings.

RESULTS

The initial survey included 190 pBE infants, indicating an incidence of approximately 10 per year. Clinical information was available for 142 of them. The median gestational age was 26 weeks and the median birthweight was 883 g. As to neonatal complications, 20% had none, 25% had one complication, 54% had two or more. Head control was observed in 45% and functional gait in 8%. Purposeful hand use was seen in 41% of patients and verbal communication in 40%. MRI showed T2 hyperintensities in the globi pallidi in 111 of 136 patients, especially between 7 and 18 months of corrected age. ABR abnormalities were present in 88 of 117 patients.

CONCLUSIONS

pBE was infrequent but constantly observed during the study period, especially in very preterm infants, even in those with no severe neonatal complications. Severely impaired gross motor function and relatively preserved manual function and verbal communication were characteristic. MRI and ABR abnormalities will facilitate diagnosis.

Bilirubin-Induced Neurotoxicity in the Preterm Neonate

Bilirubin-induced neurotoxicity in preterm neonates remains a clinical concern. Multiple cellular and molecular cascades likely underlie bilirubin-induced neuronal injury, including plasma membrane perturbations, excitotoxicity, neuroinflammation, oxidative stress, and cell cycle arrest. Preterm newborns are particularly vulnerable secondary to central nervous system immaturity and concurrent adverse clinical conditions that may potentiate bilirubin toxicity. Acute bilirubin encephalopathy in preterm neonates may be subtle and manifest primarily as recurrent symptomatic apneic events. Low-bilirubin kernicterus continues to be reported in preterm neonates, and although multifactorial in nature, is often associated with marked hypoalbuminemia.

The enigma of low bilirubin kernicterus in premature infants: why does it still occur, and is it preventable?

Low bilirubin kernicterus in preterm neonates, though rare, remains an unpredictable and refractory form of brain injury. Hypoalbuminemia, co-morbid CNS insult(s), infection, and inflammation are contributing causes that, in many cases, appear to interact in potentiating bilirubin neurotoxicity. Despite compulsive attention to serum bilirubin levels, and clinical and laboratory indices of neurotoxicity risk, low bilirubin kernicterus continues to be seen in contemporary NICUs. While efforts to refine and improve current treatment guidelines are certainly needed, such revision(s) will also have to take into account the risks and benefits of any intervention, including phototherapy.

Usefulness of (1) H-MRS in differentiating bilirubin encephalopathy from severe hyperbilirubinemia in neonates

PURPOSE

To evaluate the usefulness of (1) H-MRS in differentiating bilirubin encephalopathy from severe hyperbilirubinemia in neonates.

MATERIALS AND METHODS

There were 11 patients enrolled in the neonatal bilirubin encephalopathy (NBE) group, 8 patients in the neonatal hyperbilirubinemia (NH) group, and 9 healthy, age-matched neonates were included as controls. All patients and controls underwent (1) H-MRS and conventional magnetic resonance (MR) sequences. The spectroscopic regions of interest were the bilateral basal ganglia and the thalamus, and a spatial resolution of 1.0 cm(3) was obtained.

RESULTS

Peak-area ratios of NAA/Cr and NAA/ Cho in the basal ganglia were found to be significantly lower for the NBE group compared with the NH and control groups (P < 0.05). In contrast, there was no significant difference in the NAA/Cr ratios calculated for basal ganglia of the NH and control groups. Peak-area ratios of NAA/Cr and NAA/Cho in the thalamus were decreased for the NBE group compared with the NH and control groups, but the differences were not significant (P > 0.05). There was a significant correlation between NAA/Cr ratios for basal ganglia and the total serum bilirubin (TSB) peak level in the NBE group (P < 0.05).

CONCLUSION

(1) H-MRS is useful in the differential diagnosis of NBE from severe hyperbilirubinemia in neonates, especially when the symptoms of NBE are atypical (subtle) and MRI does not reveal clear abnormalities.