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ORIGINAL ARTICLE
Year : 2020  |  Volume : 9  |  Issue : 2  |  Page : 125-131

Study of hepatic enzymes in term neonates with perinatal asphyxia


Department of Paediatrics, MGIMS, Sewagram, Wardha, Maharashtra, India

Date of Submission25-Oct-2019
Date of Decision26-Dec-2019
Date of Acceptance26-Jan-2020
Date of Web Publication21-Apr-2020

Correspondence Address:
Dr. Vibha Kariya
Quarter No 6, Vivekananda Colony, Behind Dean Office, MGIMS, Sewagram, Wardha - 442 102, Maharashtra
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jcn.JCN_116_19

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  Abstract 


Introduction: Perinatal asphyxia is among the three most common causes of neonatal deaths. Neonates with birth asphyxia suffer from hypoxic ischemic encephalopathy. They also develop multiorgan dysfunction including hepatic injury which leads to increase in liver enzymes in the blood. In this case control study, we studied the severity of liver dysfunction in term neonates with perinatal asphyxia as compared to normal neonates. Materials and Method: This case control study was conducted in the Department of Paediatrics of a tertiary care hospital in central rural India from January 2016 to June 2017. 75 term neonates were recruited in the study as cases and sex – matched 150 term neonates without birth asphyxia as controls. Basic socio- demographic factors, obstetrical history, birth weight, gestational age, apgar score of the neonates at 1 minute and 5 minutes were noted. Serum alkaline phosphatase (ALP), alanine transaminase (ALT) and aspartate transaminase (AST) were measured at 72 ± 2 hrs. Data was analyzed to understand the strength of relationship between enzyme levels and severity of asphyxia. Result: Mean Serum alanine transaminase (ALT) and aspartate transaminase (AST) in cases (90.44 U/L and 114.56 U/L respectively) were found to be significantly higher than in controls (28.34 U/L and 71.48 U/L respectively). There was no significant correlation in serum alkaline phosphatase in these groups. There was statistically significant negative correlation between Apgar scores and Serum alanine transaminase (ALT) and aspartate transaminase (AST).
Conclusion: In the present study, we found a significant correlation between presence of a low Apgar score and raised serum alanine transaminase and aspartate transaminase. These biochemical parameters indicate the presence of hepatic dysfunction in asphyxiated neonates.

Keywords: Hypoxic ischemic encephalopathy, perinatal asphyxia, serum transaminases Hypoxic ischemic encephalopathy, perinatal asphyxia, serum transaminases


How to cite this article:
Kariya V, Jain M, Jategaonkar S. Study of hepatic enzymes in term neonates with perinatal asphyxia. J Clin Neonatol 2020;9:125-31

How to cite this URL:
Kariya V, Jain M, Jategaonkar S. Study of hepatic enzymes in term neonates with perinatal asphyxia. J Clin Neonatol [serial online] 2020 [cited 2020 Oct 24];9:125-31. Available from: https://www.jcnonweb.com/text.asp?2020/9/2/125/283024




  Introduction Top


Perinatal asphyxia is defined, as per the World Health Organization (WHO), as the failure to initiate and sustain breathing at birth. It is also defined as a temporary interruption of oxygen availability that implies a risky metabolic challenge, even when the insult does not lead to a fatal outcome.[1]

Globally, perinatal asphyxia (23%) is among the three most common causes of neonatal deaths.[2] The worldwide incidence of perinatal asphyxia is 1–6/1000 live full-term births[3] The WHO estimates that each year, between four and nine million newborns develop birth asphyxia. Among these, an estimated 1.2 million die and almost the same number develop severe long-term complications.[4]

Birth asphyxia is diagnosed clinically using Apgar score which was developed as an objective tool that measures five signs of physiologic adaptation which are heart rate, respiratory effort, muscle tone, reflex irritability, and color.[5] The mortality and the presence of significant brain damage correlate better with the 5-min as compared to the 1-min score.[6] According to the WHO classification of diseases (ICD10), severe birth asphyxia is defined as an Apgar score of 0–3 at 1 min, whereas mild and moderate birth asphyxia is defined as an Apgar score of 4–7 at 1 min.[6],[7],[8]

The hypoxic-ischemic insult to the fetus results in initiation of a series of protective reflexes, called diving sea reflexes, which prevent damage to more vital organs (brain, heart, and adrenals) at the expense of lesser vital organs (kidney, lungs, gastrointestinal tract, liver, and spleen) in an attempt to redistribute available blood flow.[9],[10],[11]

Hypoxic hepatic injury (HHI) denotes injury caused to the hepatocytes by birth asphyxia. It is characterized by a sudden rise in levels of aspartate transaminase (AST) and alanine transaminase (ALT) starting soon after hypoxic insult, reaching a peak after 24–72 h of injury and returning to normal after 7–10 days.[12],[13],[14] The mean values of transaminases, in a normal non-asphyxiated neonate, are higher than that of the adult reference values. This is because of the higher permeability of neonatal hepatocellular cell membrane. It may also be due to increased biosynthetic activity in the liver, skeletal muscle trauma at birth, and increased erythrocyte breakdown after birth.[12],[13]

Few studies have shown a significant correlation between the elevation of hepatic enzymes and severity of hypoxic ischemic encephalopathy (HIE).[14] The full-term asphyxiated neonates who develop HIE have significantly elevated levels of AST, ALT, and lactate dehydrogenase at birth and within the first 24 h of life. This elevation of enzymatic activity at birth is suggestive of a perinatal hypoxic-ischemic event which may also be associated with the development of HIE. However, even those asphyxiated neonates that do not suffer from HIE show an elevated enzymatic activity but at a lower level. Perinatal asphyxia contributes to a generalized enzyme elevation in asphyxiated neonates. This elevation is more pronounced in cases of HIE. The higher the degree of HIE, the higher the activity of AST and ALT.[15] Thus, the levels of AST and ALT may correlate with the severity of birth asphyxia. While aspartate transaminases (AST) and alanine transaminases (ALT) are markers of hepatocellular injury, bilirubin and alkaline phosphatase are indicators of hepato- biliary dysfunction and cholestasis.[16],[17] Severe neonatal asphyxia may be complicated by cholestasis in about 10% cases indicated by raised ALP.[18]

Very few studies on liver dysfunction in term neonates with birth asphyxia have been conducted in India. The study population in most available studies from India is urban. The results of studies that have been conducted in western countries or even in urban India cannot be extrapolated to the rural population. Hence, studies based on the rural Indian population on this subject are needed. In this case–control study, the severity of liver dysfunction in term neonates with perinatal asphyxia was compared to babies without perinatal asphyxia.


  Materials and Methods Top


This study was a case–control study conducted in the department of pediatrics of a tertiary care hospital in central rural India from January 2016 to June 2017 for the assessment of the relationship between birth asphyxia and levels of hepatic enzymes. Using a convenient sampling method, 75 term neonates (Gestation age ≥37 weeks) diagnosed with birth asphyxia with Apgar score at 1 min <7 were recruited in the study as cases. Sex-matched term 150 neonates without evidence of birth asphyxia (Apgar score at 1 min ≥7) and with no other abnormality were recruited as controls to achieve a 1:2 ratio of cases and controls.

Neonates with birth weight <2000 g and the neonates with any major congenital anomaly were not included in the study either as cases or controls. Neonates with opium or anesthesia-related low APGAR score were also excluded. All the babies who were preterm were excluded from the study because Apgar scores of non-asphyxiated preterm neonates are normally low due to poor neurological maturity.

Written informed consent was obtained from parents/legal guardians of the study participants. The consent forms were prepared in all three languages, i.e., English, Hindi, and Marathi. Data collection form for cases and controls contained the information on basic sociodemographic factors, details about obstetrical history of the mother, perinatal history of the neonate, birth weight of the baby, gestational age, and neonatal examination to rule out congenital anomalies. It was used to record the Apgar score of the neonate at 1 min, 5 min, and 10 min. All the neonates were attended by pediatric resident trained in neonatal resuscitation protocol. The mode and duration of resuscitation were recorded in each case.

According to the WHO classification of diseases (ICD10), severe birth asphyxia is defined as an Apgar score of 0–3 at 1 min, whereas mild and moderate birth asphyxia is defined as an Apgar score of 4–7 at 1 min.[6],[7],[8] However, according to the National Neonatal Forum, 1 min Apgar score of 7 is considered normal.[19] In this study, birth asphyxia has been classified as mild to moderate (Apgar score of 4–6) and severe (Apgar score of 0–3) on the basis of Apgar score at 1 min. The presence of HIE was noted. Whenever HIE was present, it was further graded using the Sarnat and Sarnat staging of HIE.[20] The cases diagnosed with HIE were treated according to the hospital protocol including supportive care, seizure management, and therapeutic cooling.

In all participants, samples for ALP, ALT, and AST were collected at 72 ± 2 h and were measured by the principle of photometry by random access analyzer “EM 360/XL 300.” The normal reference value for ALT and AST was taken to be 6–40 U/L[21] and 35–100 U/L, respectively.[21] The normal reference value for ALP was taken to be 145–420 U/L.[21]

Data were analyzed using SPSS 22.0 version (UNICOM Global, California, USA) and Graph Pad Prism 6.0 version (GraphPad Software, Inc., San Diego, California, USA). Chi-square test, z-test for the difference between two proportions, regression, and odd's ratio were applied to test the association between birth asphyxia and hepatic enzymes. Pearson correlation coefficient was used to measure the association between Apgar score and other parameters wherever necessary. P < 0.05 was considered as statistically significant.


  Results Top


A total of 225 neonates were included in the study after taking informed consent from the parents. Seventy-five neonates with birth asphyxia were cases and 150 normal neonates as controls. The ratio of cases to controls in the study was 1:2.

Of the 75 cases included in the study, 39 (52%) were male and 36 (48%) were female, whereas out of 150 controls, 78 (52%) were male and 72 (48%) were female. The ratio of male: female was found to 1.08:1 for both cases and controls as shown in [Table 1].
Table 1: Comparison of various parameters in the study groups

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The mean weight for 75 cases was found to be 2602.57 (standard deviation [SD] ± 353.77) grams, whereas the mean weight for 150 controls was 2686.73(SD ± 363.23) grams. There was no significant difference between the mean birth weights of neonates with birth asphyxia and normal neonates.

Out of the 75 neonates with birth asphyxia, 48 (64%) were appropriate for gestational age (AGA), whereas 103 (68.67%) out of 150 controls were AGA. There was no significant difference between the cases and controls (P = 0.48). In our study, 50 (66.67%) out of 75 neonates with birth asphyxia were born by vaginal delivery, 22 (29.33%) by lower segment caesarean section (LSCS), and 3 (4%) using forceps, whereas in the control group, 109 (72.67%) neonates were born by vaginal delivery, 38 (25.33%) were delivered by LSCS, and 3 (2%) using forceps. There was no statistical difference in the mode of delivery in the two groups. The two groups were comparable to each other.

In our study, 31 neonates had severe asphyxia, whereas 44 neonates had mild-to-moderate asphyxia based on the Apgar score at 1 min. All the 150 controls had normal Apgar score at 1 min.

Out of the 75 cases with birth asphyxia, 31 cases had no evidence of HIE, whereas 22 (29.3%) had Stage1 HIE, 15 (20%) had Stage 2, and 7 (9.3%) had stage 3 HIE.

Alanine transaminase

As shown in [Table 2], out of 150 controls, only 23 (15.33%) had raised serum ALT levels. However, out of 75 neonates with birth asphyxia based on Apgar score at 1 min, 38 (50.66%) had raised serum ALT. Among 75 cases, 64.52% of cases with severe asphyxia and 40.61% of cases with mild-to-moderate asphyxia had raised serum ALT levels. Chi-square value was found to be 36.71 which was statistically significant. Odd's ratio for the association between severity of birth asphyxia and the presence of raised serum ALT levels was found to be 5.6 times more in cases compared to controls and which was found to be significant.
Table 2: Distribution of neonates on the basis of serum alanine transaminase

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Aspartate transaminase

Out of 150 controls, only 29 (19.33%) had raised serum AST levels. However, out of 75 neonates with birth asphyxia based on Apgar score at 1 min, 31 (41.33%) had raised serum AST. Among 75 cases, 61.29% of cases with severe asphyxia and 27.27% of cases with mild-to-moderate asphyxia had raised serum AST levels. Chi-square value was found to be 23.13 which was statistically significant. Odd's ratio for the severity of birth asphyxia and the presence of raised serum AST levels was found to be 2.9 times in cases compared to controls, and it was statistically significant as shown in [Table 3].
Table 3: Distribution of neonates on basis of serum aspartate transaminase

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Alkaline phosphatase

Out of 150 controls, only 2 (1.33%) had raised serum ALP levels. However, out of 75 neonates with birth asphyxia based on Apgar score at 1 min, 5 (6.66%) had raised serum ALP. Among 75 cases, 9.68% of cases with severe asphyxia and 4.55% of cases with mild-to-moderate asphyxia had raised serum ALP levels. Chi-square value was found to be 6.30 which was not significant (P value - 0.053). Odd's ratio for severity of birth asphyxia and presence of raised serum ALP levels was found to be 5.26 times in cases compared to controls, and it was not statistically significant as shown in [Table 4].
Table 4: Distribution of neonates on basis of serum alkaline phosphatase

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To find out correlation between various biochemical markers and Apgar scores at 1 minute and at 5 minutes, Pearson correlation coefficient was used. We identified significant negative correlation between Apgar scores at 1 minute as well as 5 minutes and serum ALT, AST as shown in [Table 5] and represented graphically in [Figure 1]. Similarly, there was a negative correlation between serum ALP and Apgar score at 1 minute and 5 minutes. However, the relation was not statistically significant.
Table 5: Correlation between biochemical parameters and Apgar score at 1 min and 5 min

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Figure 1: Correlation between hepatic enzymes and Apgar score at 1 min and 5 min

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  Discussion Top


Birth asphyxia continues to be a global health problem. It is the second most common cause of neonatal deaths worldwide and is also associated with multiorgan dysfunction and poor neurological outcome due to the development of HIE. Multiorgan dysfunction in birth asphyxia occurs in the form of tricuspid regurgitation, persistent pulmonary hypertension, myocardial ischemia, HHI, and renal failure.

Apgar score continues to be an important method for the rapid assessment of the newborn. Although it correlates poorly with the neurological outcome of birth asphyxia, it still remains relevant in the 21st century.

In the present study, 31 neonates had severe asphyxia, whereas 44 neonates had mild-to-moderate asphyxia based on the Apgar score at 1 min. All the 150 controls had normal Apgar score at 1 min. The ratio of mild-to-moderate and severe asphyxia in this study was 1.4:1.

Bang et al.[22] in their study of home-based deliveries reported 26 cases of severe asphyxia and 81 cases of mild-to-moderate asphyxia. The ratio of mild-to-moderate and severe asphyxia in their study was 3.1:1 in contrast to a larger proportion of severe asphyxia in the present study. This study was a hospital-based study where a large number of complicated high-risk deliveries are conducted leading to higher incidence of severe asphyxia.Casey et al.[23] in their study reported 92 cases of severe asphyxia and 556 cases of mild-to-moderate asphyxia at 5 min out of 13,399 neonates. The ratio of mild-to-moderate and severe asphyxia in their study was 6.04:1.

In the present study, at 5 min, 12 neonates had severe asphyxia and 52 neonates had moderate asphyxia in the ratio of 4.3:1, which was similar to the study by Casey et al.[23]

Biochemical parameters

Alanine transaminase

In this study, we observed a statistically significant difference in the serum ALT levels between cases and controls. The mean value of serum ALT in neonates with asphyxia was 90.44U/L, whereas in normal neonates, the value was 28.34 U/L. Chi-square value was found to be 36.71 which was statistically significant.

As shown in [Table 6], various studies have reported a statistically significant difference in serum ALT levels in neonates with asphyxia and healthy neonates. However, Reddy et al.[24] reported no significant difference in serum ALT in cases with birth asphyxia and controls. These studies measured liver enzymes in study participants at about 3 days of birth. In these studies, birth asphyxia was defined using Apgar scores at 1 and 5 min similar to the present study.
Table 6: Various studies depicting the difference in mean alanine transaminase between asphyxiated neonates and healthy controls

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Aspartate transaminase

In the present study, we observed a statistically significant difference in the serum AST levels between cases and controls. The mean value of serum AST in neonates with asphyxia was 114.56 U/L, whereas in healthy neonates, it was 71.48 U/L. Chi-square value was found to be 23.13 which was statistically significant.

Various studies have reported a statistically significant difference in serum AST levels in neonates with asphyxia and healthy neonates as shown in [Table 7]. However, Reddy et al.[24] reported no significant difference in serum AST in cases with birth asphyxia and controls.
Table 7: Various studies depicting the difference in mean aspartate transaminase between asphyxiated neonates and healthy controls

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AST and ALT are both released in the blood at the time of hepatic injury. HHI denotes injury caused to the hepatocytes by birth asphyxia. It causes an increase in levels of AST and ALT starting soon after hypoxic insult, which reaches its peak after 24–72 h of injury and declines to normal in 7–10 days.[14]

Alkaline phosphatase

In this study, no statistically significant difference was seen in the serum ALP levels between cases and controls. The mean value of serum ALP in neonates with asphyxia was 178.57 U/L, whereas in healthy neonates, it was 175.04 U/L. Chi-square value for relation between serum ALP in term asphyxiated neonates and controls was found to be 6.30 (P = 0.053) which was not statistically significant.

In the liver, ALP is found in the microvilli of bile canaliculi and on the sinusoidal surface of hepatocytes. Cholestasis increases the synthesis and release of ALP into the bloodstream. Postasphyxic cholestasis is a rare complication of severe neonatal asphyxia which is seen in about 10% of severely asphyxiated newborn infants.[18]

In a case–control study by Islam et al.,[25] the mean serum ALP in asphyxiated neonates was 369 U/L, whereas in controls, it was 208 U/L. There was a significant difference in serum ALP between cases and controls (P < 0.001). Choudhary et al.[9] in their case–control study of hepatic enzymes in neonates with birth asphyxia, also found a significant difference (P < 0.001) in serum ALP in asphyxiated neonates (341.01 U/L) and healthy neonates (254.8 U/L).

The findings of these studies from different settings may not be consistent with the findings of our study. The reason might be due to small sample size, single-center study with hospital-based population.

Hepatic enzymes may help to detect the severity of perinatal asphyxia, especially if previous birth records are absent and in a setup where higher investigations such as cord blood PH are not available. Thus, early treatment can be initiated on the basis of liver function tests. However, further research in this regard is necessary.


  Conclusion Top


In the present study, we found a significant correlation between the presence of a low Apgar score and raised serum ALT and AST. These biochemical parameters indicate the presence of hepatic dysfunction in asphyxiated neonates.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

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    Figures

  [Figure 1]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]



 

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