Dialogs in the assessment of neonatal cholestatic liver disease

Neonatal cholestatic liver disease is rarely encountered by pathologists outside of specialized pediatric centers and navigating the long list of potential diseases can be daunting. However, the differential diagnosis can be rapidly narrowed through open conversations between the pathologist and pediatric gastroenterologist. The dialog should ideally begin before obtaining the liver biopsy and continue through the rendering of the final pathologic diagnosis. Such dialogs are necessary to first ensure the proper handling of the precious sample and then to allow for synthesis of the clinical, laboratory, imaging, and genetic data in the context of the histologic features seen in the liver biopsy. In this review, we aim to provide a broad template on which such dialogs may be based and pitfalls that may be encountered on both the clinical and pathologic sides. This review will focus on non-biliary atresia etiologies of neonatal cholestasis, including select infectious, genetic, and metabolic entities.

A practical approach to the pathology of neonatal cholestatic liver disease

Navigating the complexities of interpreting a liver biopsy performed on a neonate with conjugated/direct hyperbilirubinemia can be an arduous task given these biopsies are infrequently encountered. The list of entities is long and yet there are only a few histologic patterns of liver injury. The first step for the pathologist is to determine the histologic pattern, which will guide further inquiry into the useful clinical information to have while evaluating the biopsy. Ultimately, the goal is to identify those conditions that will benefit from early intervention. We begin with a review of biliary development to help understand what findings may be physiologic versus pathologic, particularly in premature infants. Then we review eight cases that cover the three most common histologic patterns of injury in patients with neonatal cholestasis: biliary obstructive, neonatal hepatitis, and paucity of intrahepatic bile ducts. The entities that serve as prototypes for these histologic patterns are covered, including biliary atresia, idiopathic neonatal hepatitis, and Alagille syndrome, along with rarer entities that have histologic overlap. The cases with accompanying tables and algorithms are intended to help place the histologic findings in the context of the overall clinical work-up, including genetic testing.

Hepatitis B viral infection of hepatic progenitor cells. Resolving unresolved questions?

Accumulated data to date do not entirely explain the; propensity of the hepatitis B virus (HBV) to cause chronic infections in newborns; failure of antiviral agents to resolve infections or precise mechanism whereby HBV causes hepatocellular carcinoma (HCC). Based on the increased numbers of hepatic stem/progenitor cells (HPCs) present within the neonatal liver, the refractoriness of these cells to the effects of interferons and xenobiotics and their ability to undergo malignant transformation, we hypothesize that HBV infection of HPCs could explain these and perhaps other clinical features of chronic HBV.

Biopsy-driven diagnosis in infants with cholestatic jaundice in Iran

AIM: To determine the frequencies of diagnoses confirmed by liver biopsy in infants with cholestasis in an Iranian pediatric hospital.

METHODS: This was a retrospective study conducted in a tertiary referral children’s hospital in Iran. We retrieved all pathology reports of liver biopsies from children less than two years of age who had presented for evaluation of cholestatic jaundice from March 2001 to March 2011. Additional specimen samples obtained from archived pathology blocks were reviewed by a pathologist blinded to the final diagnosis. These results were compared with the pathology reports from chart records to ensure consensus and eliminate any inconsistencies in final diagnoses. A structured checklist was used to gather information on multiple variables including age, sex, gestational age at birth, birth weight, age at which hyperbilirubinemia manifested, presence and identification of associated anomalies, clinical manifestations, and histological findings from liver biopsies. The baseline data are reported using descriptive statistics, and differences between groups were assessed by Fisher’s exact test and Student’s t test when indicated.

RESULTS: Fifty-five cases (28 females; 27 males) of infantile cholestasis (IC) were included in this study. The mean serum total bilirubin and direct bilirubin at presentation were 13.6 ± 5.9 and 7.3 ± 3.4, respectively. Forty cases (72.7%) were the product of term pregnancies. Common associated clinical findings were acholic stool in 33 cases (60.0%), hepatomegaly in 30 cases (54.5%), and dark-colored urine in 21 cases (38.2%). Biliary atresia (BA) was the most frequent diagnosis, found in 32 cases (58.2%), followed by intrahepatic bile duct paucity found in 6 cases (10.9%), metabolic disease in 6 cases (10.9%), idiopathic neonatal hepatitis in 5 cases (9.1%), choledochal cyst in 2 cases (3.6%), liver cirrhosis in 2 cases (3.6%), and progressive familial intrahepatic cholestasis and portal fibrosis each in 1 case (1.8%). The mean times for jaundice onset and liver biopsy were 43.8 and 102.0 d, respectively. In BA, the mean age at jaundice presentation was 21 d and for liver biopsy was 87.5 d, representing a mean delay of 66.5 d.

CONCLUSION: A significant delay was found between IC presentation and liver biopsy, which is detrimental in conditions that can cause irreversible liver damage, such as BA.

Diagnosis in bile acid-CoA: Amino acid N-acyltransferase deficiency

Cholate-CoA ligase (CCL) and bile acid-CoA: amino acid N-acyltransferase (BAAT) sequentially mediate bile-acid amidation. Defects can cause intrahepatic cholestasis. Distinction has required gene sequencing. We assessed potential clinical utility of immunostaining of liver for CCL and BAAT. Using commercially available antibodies against BAAT and CCL, we immunostained liver from an infant with jaundice, deficiency of amidated bile acids, and transcription-terminating mutation in BAAT. CCL was normally expressed. BAAT expression was not detected. Immunostaining may facilitate diagnosis in bile-acid amidation defects.

Spectrum of phenotypic variability in Niemann-Pick type C disease: A cause of delayed diagnosis

BACKGROUND

Niemann-Pick type C (NP-C) disease exhibits marked heterogeneity in its phenotype. This can pose diagnostic dilemmas and even delayed recognition of this condition.

OBJECTIVE

To highlight the phenotypic variations and distinctive pathological and biochemical findings in this disorder.

DESIGN

Descriptive case studies.

SETTING

Tertiary care children's hospital and clinic.

POPULATION STUDIED

Three cases of NP-C disease where diagnosis was delayed.

RESULTS

In each of the three cases the clinical presentation was varied, one as neonatal hepatitis, the second with megaloblastic anemia, chronic hepatitis and short stature, and the third with neonatal hepatitis and chronic respiratory failure. Definitive diagnosis was established in each case by demonstration of defective cholesterol esterification in skin fibroblasts.

CONCLUSIONS

In the clinical setting of neonatal hepatitis, hepatosplenomegaly and undiagnosed neurological symptoms, NP-C disease should be considered in the differential diagnosis. Electron microscopic examination of skin biopsy is an effective screening test, although the definitive diagnosis should be made by the cholesterol esterification assay and filipin staining.

The molecular and antigenic tissue impact of viral infections on liver transplant patients with neonatal hepatitis

BACKGROUND

Pathogenesis of neonatal hepatitis relates to various underlying causes including viral infections. Both hepatotropic and non-hepatotropic viruses may induce liver failures in infants before birth, during delivery, or shortly after birth.

OBJECTIVES

The tissue impact of HCMV, HSV, HBV, HCV, and rotavirus and adenovirus infections was evaluated in studied infants with neonatal hepatitis.

METHODS

The history of viral infections was analyzed in paraffin-embedded biopsy and autopsy tissues of 22 infants with neonatal hepatitis between years 1996 and 2007, retrospectively. The tissue molecular presentation of HBV, HCV, HCMV, HSV, adenovirus, and rotavirus was evaluated by different qualitative simple and nested PCR and RT-PCR protocols. Immunohistochemistry (IHC) method was used for studying the antigenic prevalence of HSV-1, 2; HBV, HCMV and adenovirus infections. Also the laboratory liver indices of all patients with neonatal hepatitis were analyzed.

RESULTS

The HBV and HSV genomes were detected in 3 (14%) of 22 infants. The rotavirus and HCV-RNA and also the HCMV-DNA were detected separately in 1 (4%) of 26 paraffin-embedded autopsy and biopsy tissues. The HBV and HSV-1 specific antigens were separately diagnosed in 1 (4%) of 26 neonatal samples by IHC protocols. Also the HSV-2 antigen was seen in 5 (23%) of 22 liver autopsy and biopsy specimens. Co-infections with HCMV, HSV, HBV, HCV, and rotavirus were detected in these infants with hepatitis.

CONCLUSION

Diagnosis of single and mixed molecular and antigenic traces of HCMV, HSV, HBV, HCV and rotavirus underlines the etiologic role of these viruses in clinical pathogenesis of neonatal hepatitis.

Jaundice in a neonate with congenital diaphragmatic hernia

A six-week-old boy presented to the emergency department with worsening jaundice. His medical history included congenital diaphragmatic hernia repaired shortly after birth. Significant jaundice, unresponsive to phototherapy, was noted on the eighth day of life. His total bilirubin level decreased when he was advanced to full oral feeds. However, on the 23rd day of life, the patient's conjugated bilirubin level had tripled. This was attributed to total parenteral nutrition, and the patient was discharged home. Over the next month, his jaundice worsened. The patient was readmitted and ultimately diagnosed with cytomegalovirus (CMV) hepatitis. After treatment with ganciclovir, his hepatitis completely resolved. CMV infection is a common cause of neonatal hepatitis and congenital malformation. Prolonged neonatal jaundice that does not improve with transitioning from total parenteral nutrition to oral feeds warrants further evaluation. Simple laboratory investigation can avoid unnecessary and potentially harmful medical and surgical interventions. Early treatment of neonatal CMV infection reduces the risk of long-term neurological and hepatic complications.