Biliary Atresia and Cytomegalovirus and Response to Valganciclovir

Etiology and outcome of neonatal cholestasis: an experience in a tertiary center of Bangladesh

Background

Neonatal cholestasis (NC) is a major cause of morbidity and mortality in young infants. This study examines the etiology of NC and its outcome during 2 years of follow-up at a tertiary referral center in Bangladesh.

Results

Out of 80 cholestatic infants, 60% had intrahepatic cholestasis with a mean age of onset of 12.4±2.8 days and a mean age of admission of 82.4±29.0 days. The remaining 40% were extrahepatic with a mean age of onset of 6.7±2.3 days and a mean age of admission of 94.6±50.4 days. Biliary atresia (BA), idiopathic neonatal hepatitis (INH), and TORCH (Toxoplasma, rubella, cytomegalovirus, and herpes simplex) infection except rubella were the most common causes. After receiving treatment, 46.2% of the cases improved, 23.8% deteriorated with morbidity, and 30% died. The majority of the children with INH, TORCH, choledochal cyst, hypothyroidism, galactosemia, and urinary tract infection (UTI) with sepsis were improved. Significant mortality was found in BA (56.6%), intrahepatic bile duct paucity (PIBD) (100%), and progressive familial intrahepatic cholestasis (PFIC) (100%) whereas the rest of BA (43.4%) live with persistent morbidity. Significant clinical improvement was observed in 37 (46.2%) cases of cholestasis evidenced by decreasing jaundice, change of color of urine from dark to normal color, change of stool color from pale to yellow, and gradual decrease in liver size from hepatomegaly state. In addition, decreasing median total bilirubin, direct bilirubin, alanine transaminase, gamma-glutamyl transferase, and alkaline phosphatase showed biochemical improvement at 2 years follow-up. The age of admission, etiology, and presence of ascites are the predictors of outcomes.

Conclusion

BA was the most common cause of extrahepatic while INH and TORCH infection were the most common cause of intrahepatic cholestasis. Majority of children with intrahepatic cholestasis improved but deteriorated with BA and genetic causes. Prompt referral and early diagnosis as well as the etiology of NC were the main determinants of the favorable outcome.

Update on Etiology and Pathogenesis of Biliary Atresia

Biliary atresia is a rare inflammatory sclerosing obstructive cholangiopathy that initiates in infancy as complete choledochal blockage and progresses to the involvement of intrahepatic biliary epithelium. Growing evidence shows that biliary atresia is not a single entity with a single etiology but a phenotype resulting from multifactorial events whose common path is obliterative cholangiopathy. The etiology of biliary atresia has been explained as resulting from genetic variants, toxins, viral infection, chronic inflammation or bile duct lesions mediated by autoimmunity, abnormalities in the development of the bile ducts, and defects in embryogenesis, abnormal fetal or prenatal circulation and susceptibility factors. It is increasingly evident that the genetic and epigenetic predisposition combined with the environmental factors to which the mother is exposed are potential triggers for biliary atresia. There is also an indication that a progressive thickening of the arterial middle layer occurs in this disease, suggestive of vascular remodeling and disappearance of the interlobular bile ducts. It is suggested that the hypoxia/ischemia process can affect portal structures in biliary atresia and is associated with both the extent of biliary proliferation and the thickening of the medial layer.

Detection of Cytomegalovirus Infection in Infants with Biliary Atresia: A Meta-analysis

Objectives  Biliary atresia (BA) is the most common indication of liver transplantation in children. Several reports attributed BA to both prenatal and perinatal etiologies, including a viral infection-induced autoimmune response that targets the bile ducts. Cytomegalovirus (CMV) remains the most common virus being linked to BA. This meta-analysis aimed to estimate to what extent CMV infection is detected in patients with BA.

Methods  This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The databases of MEDLINE, Embase, Scopus, WHO-Virtual Health Library (VHL), ScienceDirect, and Google Scholar were used for the systematic search. The risk of bias was assessed using the Newcastle–Ottawa scale. Random effects model was used to estimate the pooled prevalence estimate with the corresponding 95% confidence interval (CI) using Comprehensive Meta-Analysis Software version 3.3.

Results  A total of 19 studies that fulfilled the eligibility criteria were included in the meta-analysis. The total number of infants with BA was 630 patients, and the pooled overall prevalence of CMV infection among them was 25.4% (95% CI: 15.9%–38.0%). There was high heterogeneity among studies (I ²  = 85.1%, p  < .001), and subgroup analyses showed significant regional differences (X ²  = 48.9, p <.001). Data on the prognosis of CMV-associated BA were scarce and obtainable from few studies that suggested an association between detection of CMV infection and poor prognosis of BA.

Conclusions  The limited available data demonstrates that the rate of detection of CMV infection is high in infants with BA. There is still a need for large studies with appropriate controls for obtaining more reliable results about the various aspects of the association between CMV infection and BA.

Adjuvant treatments for biliary atresia

The treatment of biliary atresia (BA) is predominantly surgical with firstly an attempt at restoration of bile flow from the native liver by wide excision of the obstructed, obliterated extrahepatic biliary tree to the level of the porta hepatis and a portoenterostomy using a long Roux loop-Kasai portoenterostomy (KPE). Liver transplantation is reserved for those that fail this and for those where surgery is considered futile for reasons of age or stage of disease. As the aetiology of BA remains ill-defined, so adjuvant treatment has been largely based on pragmatism, trial and error. Systematic analysis of the few randomized placebo-controlled trial data and less well-controlled cohort studies have suggested benefit from post-operative high-dose steroids and ursodeoxycholic acid (UDCA) while the benefit of long-term prophylactic antibiotics, bile acid sequestrants (e.g., colestyramine) or probiotics remains unproven. Newer modalities such as antiviral therapy (AVT), immunoglobulin, FXR agonists (e.g., obeticholic acid), ileal bile acid transporter (IBAT) antagonists (e.g., maralixibat) remain unproven. This article reviews the current evidence for the efficacy of adjuvant medical therapy in BA.

Adjuvant therapy in biliary atresia: hopelessly optimistic or potential for change?

Given that the aetiology of biliary atresia (BA) is complex and that there is a multiplicity of possible pathogenic mechanisms then it is perhaps not surprising that the evidence for effect of a number of different agents is contradictory. Post-operative cholangitis for instance is common, bacterial in origin and various antibiotic regimens have been tested (although none in a randomized trial) but continuation beyond the early post-operative period does not appear to offer any greater protection. There is an inflammatory reaction in about 25-35% of cases of BA illustrated by abnormal expression of class II antigen and upregulation of ICAM, VCAM and E-selectin with an infiltrate of immune-activated T cells (predominantly CD4 + Th1 and Th17) and NK cells and a systemic surge in inflammatory cytokines (e.g. TNF-α, IL-2, IL-12). This has potential as a therapeutic target and is the main hypothesis behind the rationale use of steroids. The first report of steroids was published in 1985 by Karrer and Lilly as "blast" therapy to treat recalcitrant cholangitis, followed by a multiplicity of small-scale uncontrolled studies suggesting benefit. To date there has been one randomized placebo-controlled study with a low-dose (prednisolone 2 mg/kg/day) regimen (2007); one with a high-dose (IV prednisolone 4 mg/kg/day regimen) (2014); two prospective high-dose open-label studies (2013); a prospective comparison of low- and high-dose regimen and a large (380 infants) retrospective comparison. The most recent meta-analysis (2016) identified a significant difference in clearance of jaundice at 6 months (OR 1.59, 95% CI 1.03-2.45, P = 0.04), in patients treated with high-dose steroids, particularly if < 70 days at surgery. Ursodeoxycholic acid (UDCA) may increase choleresis or change the ratio of endogenous bile acids to a less hydrophobic and, therefore, less toxic millieu. UDCA may protect cholangiocyte membranes against damage and perhaps reduce the tendency to fibrogenesis. Biochemical benefit has been shown in a single crossover trial in older BA children who had cleared their jaundice. Other potential adjuvant therapies include immunoglobulin therapy, anti-viral agents and Chinese herbs although real evidence of benefit is lacking.

Early and Peri-operative Prognostic Indicators in Infants Undergoing Hepatic Portoenterostomy for Biliary Atresia: a Review

PURPOSE OF REVIEW

Biliary atresia is the most common indication for liver transplantation among children. In recent years, prospective, multi-centre collaboration has been underway with the aim of providing high-quality data on the natural history of the condition, prior to and following hepatic portoenterostomy.

RECENT FINDINGS

There is increasing evidence that specific histological findings, and age, at the time of portoenterostomy have relevance as prognostic indicators. Recent data suggest that the sub-type of biliary atresia, its co-existence with other anomalies and concurrent infection may also be important variables. This review provides a comprehensive summary of the histological predictors of outcome following portoenterostomy. Later age at portoenterostomy, advanced degree of hepatic fibrosis and co-existence with other congenital anomalies are strongly correlated with poor outcomes following portoenterostomy. There is increasing evidence to suggest that common serological indices and the presence or absence of cytomegalovirus (CMV) co-infection may have utility as early prognostic indicators.

Cytomegalovirus-associated biliary atresia: An aetiological and prognostic subgroup

BACKGROUND AND AIMS

Perinatal cytomegalovirus (CMV) infection is a possible cause or trigger of biliary atresia though clinical evidence is scant. We hypothesised that CMV IgM+ve biliary atresia is a separate clinical entity compared to CMV IgM-ve biliary atresia.

METHODS

Prospective single-centre study. 210 infants with histologically confirmed biliary atresia were treated in our institution (Jan. 2004 to Dec. 2011); of these 20 (9.5%) were CMV IgM+ve at presentation. We compared these with 111 infants who were CMV IgM-ve (controls) for clinical features, biochemistry at presentation and outcome following Kasai portoenterostomy (KPE). A blinded comparison of age-matched liver histology was also performed. Data are quoted as median (interquartile range). A P value ≤ 0.05 was regarded as significant.

RESULTS

Infants with CMV IgM+ve biliary atresia were older at Kasai portoenterostomy (or laparotomy) [70 (60-80) days vs. 56 (44-75)days; P = 0.003] and were more jaundiced [175 (147-224) vs. 140 (121-181) μmol/L; P = 0.002+ with higher AST*287 (157-403) vs. 180 (133-254) IU/L; P = 0.005] and aspartate aminotransferase-to-platelet ratio index [1.1 (0.79-3.0) vs. 0.63 (0.43-0.95)] levels. Liver histology: CMV IgM+ve biliary atresia was characterised by a greater degree of inflammation (P < 0.0001) and fibrosis (P = 0.02), whereas CMV IgM-ve isolated biliary atresia had a higher degree of lobular cholestasis (P = 0.001). This effect was independent of the effects of age at KPE.

OUTCOME

CMV IgM+ve biliary atresia had a poorer outcome with a reduced clearance of jaundice (15% vs. 52.2%; P = 0.002), native liver survival (P < 0.0001) and increased mortality (P = 0.002).

CONCLUSIONS

CMV IgM+ve biliary atresia is a distinct clinical and pathological entity with a diminished response to Kasai portoenterostomy.