Pre-operative time course changes in liver function tests in biliary atresia: its usefulness in the discrimination of biliary atresia in early infancy

New insights in understanding biliary atresia from the perspectives on maternal microchimerism

Biliary atresia (BA) is a fibroinflammatory cholangiopathy and portal venopathy. It is of unknown etiology and is associated with systemic immune dysregulation, in which the first insult begins before birth. Maternal microchimerism is a naturally occurring phenomenon during fetal life in which maternal alloantigens promote the development of tolerogenic fetal regulatory T-cells in utero. However, maternal cells may alter the fetus's response to self-antigens and trigger an autoimmune response under certain histocompatibility combinations between the mother and the fetus. A recent report on a set of dizygotic discordant twins with BA, one of whose placentae showed villitis of unknown etiology, implies a certain immune-mediated conflict between the fetus with BA and the mother. Maternal chimeric cells persist postnatally for various time spans and can cause cholangitis, which ultimately leads to liver failure. In contrast, patients who eliminate maternal chimeric cells may retain their liver function.

Unique manifestations of biliary atresia provide new immunological insight into its etiopathogenesis

Biliary atresia (BA) is a unique cholestatic disease of newborns with a background of exaggerated immune response in the liver of unknown mechanism. Three hypotheses have been proposed; autoimmune type of cholangiopathy triggered by virus infection, graft-versus-host disease type of immune-mediated disease associated with maternal microchimerism and ductal plate malformation theory. Researchers on virus infection theory have experimentally explored immune process causing cholangiopathy on murine models of this disease, while in maternal microchimerism hypothesis were detected maternal cells in the BA patients' liver, of which roles are yet to be determined. Ductal plate malformation theory is an intriguing hypothesis in the sense that it suggests the onset of this disease is in the first trimester. This theory can be secondary to either one of these two immune-related insults. In this review, four unique points are focused; (1) the timing of onset, (2) hepatitis-like pathological picture, (3) heterogenous atrophy of the liver segments when advanced, and (4) swollen lymph nodes at the porta hepatis. These unique clinicopahtological aspects of this disease should be well explained by these hypotheses.

Value of Gamma-Glutamyl Transpeptidase for Diagnosis of Biliary Atresia by Correlation With Age

OBJECTIVES

The aim of the study was to analyze the value of gamma-glutamyl transpeptidase (GGT) for distinguishing biliary atresia (BA) from non-BA for patients suspected of having neonatal obstructive jaundice by correlation with age.

METHODS

From January 2003 to March 2014, cholangiography and/or surgical exploration were undertaken in 1469 patients with suspicion of having neonatal obstructive jaundice. A total of 1338 patients were diagnosed with BA intraoperatively. Preoperative medical records were compared between BA and non-BA patients.

RESULTS

Preoperative levels of total bilirubin, direct bilirubin, and GGT were significantly higher in the BA group (P < 0.05), whereas the non-BA group had higher alkaline phosphatase levels (P = 0.0003). The area under the receiver operating characteristic curve of total bilirubin, direct bilirubin, GGT, and alkaline phosphatase was 0.584, 0.614, 0.843, and 0.398, respectively. In all age groups (i: 31-60 days; ii: 61-90 days; iii: 91-120 days; iv: ≥121 days), BA groups had higher GGT levels (in IU/L) (i: 725.3 ± 549.9; ii: 927.0 ± 679.8; iii: 1114.3 ± 823.1; iv: 767.5 ± 666.7). The level of GGT in patients with BA younger than 30 days was 834.2 ± 475.3 IU/L. GGT levels had the highest diagnostic value (0.869) in group ii (61-90 days) and the lowest diagnosis value (0.712) in group iv (≥121 days). At a cutoff of >303 IU/L in group ii (61-90 days), GGT had 82.8% sensitivity and 81.6% specificity for the discrimination of BA.

CONCLUSIONS

GGT levels contribute to the diagnosis of BA before 120 days. Age must be considered if using GGT levels as a diagnostic test for BA.

A screening algorithm for the efficient exclusion of biliary atresia in infants with cholestatic jaundice

BACKGROUND

Neonates with cholestasis may undergo many tests before biliary atresia (BA) or an alternative diagnosis is reached, and delayed intervention may worsen outcomes. An optimal diagnostic approach to reduce risk, cost, and delay has yet to be defined. The purpose of this study was to develop an algorithm that rapidly and accurately excludes BA for infants with cholestatic jaundice.

METHODS

A single-center retrospective comparison of diagnostic workup was made between cholestatic infants with BA, and those without BA who underwent hepatobiliary iminodiacetic acid (HIDA) scan during admission. Patients were born between 2000 and 2010 and those older than 100days at assessment were excluded. Sensitivity and specificity analysis of predictive variables was performed and an algorithm constructed.

RESULTS

There were 45 BA and 167 non-BA patients. Some variables were 100% sensitive for the exclusion of BA: conjugated bilirubin <2.5mg/dL, gamma-glutamyl transpeptidase <150U/L, excretion on HIDA, or a normal percutaneous cholangiogram. Clinical variables and ultrasound were less useful as screening tests owing to low specificity and sensitivity, respectively. Liver biopsy was 98% sensitive and 84% specific in the diagnosis of BA. An algorithm was constructed that rules out BA with a negative laparotomy rate of 3-22%.

CONCLUSION

We propose a screening algorithm for infants with conjugated hyperbilirubinemia that permits efficient exclusion of BA with minimal invasive testing and with a low risk of negative laparotomy. This algorithm now requires prospective evaluation to determine its diagnostic accuracy and its ability to reduce hospital costs, patient morbidity, and time to Kasai portoenterostomy in patients with BA.

Differentiating Biliary Atresia from Other Causes of Cholestatic Jaundice

Diagnosis of biliary atresia (BA) in infants presenting with cholestatic jaundice (CJ) requires exploratory surgery with cholangiography. However, the lack of a standardized approach to pre-operative evaluation of infants with CJ can lead to a high number of negative surgical explorations. We reviewed our experience with CJ and BA to determine preoperative variables that might reliably identify BA. Infants explored for possible BA over a 5–year period were retrospectively reviewed. Preoperative clinical indices and liver biopsy results were reviewed. Statistical analysis was conducted by Student's t test and Fisher's exact test ( P < 0.05). Twenty patients were identified, 10 with BA and 10 without (50% negative exploration rate). Nuclear cholescintigraphy (HIDA) excretion into the gastrointestinal tract was absent in all BA and in 8 of 10 without BA. Hepatomegaly was more common in the BA group (OR = 9.3, P = 0.07). BA had higher mean (6 standard error) serum gammaglutamyl transpeptidase levels (542 ± 130 vs 139 ± 25.8 U/L in non-BA, P = 0.03). There were insignificant differences in sex, type of feeding, TPN exposure and sepsis between the two groups. Although our small sample size limits conclusions, we suggest screening infants with CJ by measuring GGT levels, absence of hepatomegaly, presence of cholic stools and/or excretion on HIDA scan to undergo pecutaneous liver biopsy given the lower likelihood of BA necessary.

Guideline for the evaluation of cholestatic jaundice in infants: recommendations of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition

For the primary care provider, cholestatic jaundice in infancy, defined as jaundice caused by an elevated conjugated bilirubin, is an uncommon but potentially serious problem that indicates hepatobiliary dysfunction. Early detection of cholestatic jaundice by the primary care physician and timely, accurate diagnosis by the pediatric gastroenterologist are important for successful treatment and a favorable prognosis. The Cholestasis Guideline Committee of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition has formulated a clinical practice guideline for the diagnostic evaluation of cholestatic jaundice in the infant. The Cholestasis Guideline Committee, consisting of a primary care pediatrician, a clinical epidemiologist (who also practices primary care pediatrics), and five pediatric gastroenterologists, based its recommendations on a comprehensive and systematic review of the medical literature integrated with expert opinion. Consensus was achieved through the Nominal Group Technique, a structured quantitative method. The Committee examined the value of diagnostic tests commonly used for the evaluation of cholestatic jaundice and how those interventions can be applied to clinical situations in the infant. The guideline provides recommendations for management by the primary care provider, indications for consultation by a pediatric gastroenterologist, and recommendations for management by the pediatric gastroenterologist. The Cholestasis Guideline Committee recommends that any infant noted to be jaundiced at 2 weeks of age be evaluated for cholestasis with measurement of total and direct serum bilirubin. However, breast-fed infants who can be reliably monitored and who have an otherwise normal history (no dark urine or light stools) and physical examination may be asked to return at 3 weeks of age and, if jaundice persists, have measurement of total and direct serum bilirubin at that time. This document represents the official recommendations of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition on the evaluation of cholestatic jaundice in infants. The American Academy of Pediatrics has also endorsed these recommendations. These recommendations are a general guideline and are not intended as a substitute for clinical judgment or as a protocol for the care of all patients with this problem.