Neonatal cholestasis

T H E J O U R N A L OF

PEDIATRICS FEBRUARY

1985

V o l u m e 106

Number 2

MEDICAL PROGRESS Comment:The facts and ideas set forth in this paper address a spectrum of problems that have baffled good clinicians for years. Many of our readers will remember attempts to resolve these complex problems by the use of various tests and will welcome an increased understanding of the pathophysiologic findings. We can agree that we do not yet have all the answers, but we hope our readers will join in our gratitude for a clear exposition of where we stand.--R.E.M.

Neonatal cholestasis W i l l i a m F. Balistreri, M . D . C i n c i n n a t i , O h i o

THE HETEROGENEOUS NATURE of the diseases that have

neonatal cholestasis (prOlonged conjugated hyperbilirubinemia) as the initial manifestation creates challenges in evaluation and in effective management. The list of potential causes of cholestasis in early life is long and diverse, and it is important that clinicians rapidly recognize the specific treatable metabolic or infectious entities in order to institute early, appropriate, and effective management. In many patients, however, it is difficult to pinpoint the precise nature of the aberration; this subset has been termed idiopathic obstructive infantile cholangiopathy, of which extrahepatic biliary atresia and the syndrome of neonatal hepatitis comprise the majority of the cases. Uncertainty is created because the nosology and diagnostic criteria vary and there is very little information regarding t h e pathophysiologic basis of specific causes Of neonatal cholestasis. Additional research addressing the mechanisms of initiation and perpetuation of impaired bile flow is needed in order to understand more fully this fascinating From the Children's Hospital Research Foundation. Reprint requests: William F. Balistreri, M.D., Children's Hospital Research Foundation, Elland and Bethesda Ave., Cincinnati, OH 45229.

and challenging group of diseases. The purpose of this review is to discuss new concepts regarding the genesis of neonatal cholestasis and the implications of recent observations in regard to current methods of evaluation and management. F A C T O R S P R E D I S P O S I N G TO CHOLESTASIS IN THE NEONATAL PERIOD There are several reasons why cholestasis of diverse causes may appear in the neonate: the cholestatic propensity of the newborn infant (so-called physiologic cholestasis) attributable to immaturity of hepatic excretory function, inborn errors that cause hepatic dysfunction first manifest in early life, and an inherent susceptibility to viral or toxic insult, associated with a stereotypic response of the immature hepatocyte to injury. Immaturity of the enterohepatic circulation of bile acids. Bile flow correlates with hepatic bile acid excretion (Fig. 1). Hepatic excretory function, which is dependent on the enterohepatic circulation of bile acids, is said to be dormant in the fetusi this role is replacec!~by placental excretorY function, After birth, there is a gradual maturation in the functional capacity of the liver. Transient perturbation

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BILE FLOW (p,I rnin "1 g'tliver)

BILE ACID EXCRETION RATE

(nmoles min -I g-i liver) Fig. l. Curvilinear relationship between rate of bile acid excretion from liver and volume of bile, indicating major role that bile acid output plays in generation of bile flow. Slope of line is steeper at lower rates of bile acid output. (Reprinted by permission Of Elsevier Science Publishing Co., Inc., from Cellular mechanisms of bile formation, by BL Blitzer and JL Boyer, Gastroenterology, vol 82, p 346. Copyright 9 1982 by The American Gastroenterological Association.)

of any of the processes involved in bile acid transport may occur in the immature hepatocytc and lead to an alteration in cellular bile formation, a decrease in biliary flow, and anatomic and clinical manifestations of cbolestasis. Inefficient liver cell transport of bile acids in early life is suggested by studies of fetal and suckling rats, as well as of normal human neonates, that show an elevation of serum bile acid concentrations, an indirect indication of impaired hepatic clearance. ~The magnitude of elevation is similar to that seen in adults with cholestasis and in experimental models of induced cholestasis. In contrast to the transient rise of unconjugated bilirubin concentrations in normal neonates, the elevation of serum bile acid values persists throughout the first 4 to 6 months of life? Other biochemical markers of cholestasis, alkaline phosphatase and ~,-glutamyl transpeptidase, also have transiently elevated values, which decline to adult levels in the first 6 months of life? Direct documentation of impaired uptake of bile acids in rat hepatocytes, and impaired hepatoceilular transport and excretion of organic anions corroborates further the suggestion that there is transient cholestasis in neonates? Conjugation of bile acids with the amino acids glycine and taurine or detoxification through the addition of a polar sulfate group (by means of a sulfotransferase) are important metabolic processes that function at low levels in the developing rat?. ~ In addition, bile acid pool size is contracted and intestinal luminal bile acid concentrations are low, accounting in part for the observed inefficiency of fat digestion and absorption. Qualitative and quantitative

differences exist between the immature and the mature liver in bile acid synthesis; these differences are associated with the appearance of atypical bile acids in meconium.~'6 The presence of qualitatively abnormal bile acids suggests the existence of a fetal synthetic pathway and a delay in the establishment of a mature synthetic sequence. In adults who acquire cholestatic liver disease, there is a resurgence of this fetal pattern of serum bile acids. 6 The physiologic importance and pathophysiologic effects of these compounds are Unknown and controversial. For example, certain of these atypical bile acids, such as 3/3-hydroxy-5A-cholenoic acid, may be intrinsically hepatotoxic and may initiate or exacerbate cholestasis. 1,6 On the other hand, polyhydroxylated bile acids, such as tetrahydroxycholanoic acids, are present in the urine of normal infants in concentrations comparable to those of the primary bile acids. 7 Formation of these more soluble compounds may present an efficient alternate route of elimination, and may be beneficial. Teleologic principles seem to favor the latter in order to maintain homeostasis. The net effect is that morphologic and functional aspects of both the hepatic excretory apparatus and of various metabolic processes may be slow to achieve an adult level of development. This creates the potential for a decrease in bile flow or the production of abnormal bile acids in response to perturbation. 1,6.8 The neonate, therefore, is a prime candidate for cholestasis. Exogenous insults such as sepsis may adversely affect the uniquely vulnerable infantile liver. For example, Escherichia coli endotoxin, can produce cholestasis. 9 Likewise, the intravenous infusion of amino acids during nutritional support, especially in low-birth-weight infants, may be associated with progressive liver dysfunction.~~The complex series of events often encountered by prematurely born infants (hypoxia, hypoperfusion, sepsis, medications, and diminished input of enteric hormones as a result of inability to feed) may combine to result in a marked impairment in hepatic excretory function. T M Specific data regarding issues such as the role of an amino acid (or other nutrient) deficiency or toxicity are required to allow modification of either the infusate or of the method of administration, and thus decrease the incidence or severity of cholestasis.'. ~3.~4 The clinical dilemma is whether to continue the infusion, with the inherent risk of hepatic damage, or to attempt alternate means of feeding, with the possibility of undernutrition and long-term effects on growth and development. A t the present time, a prudent course may be to attempt to initiate small-volume feedings orally while decreasing the infusion. Experiments of nature thatcause cholestasis. Inborn

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Table I. Causes of cholestasis in the neonate I. Anatomic abnormalities A. Extrahepatic 1. Biliary atresia 2. Biliary hypoplasia 3. Bile duct stenosis 4. Choledochal-pancreatico-ductal junction anomaly 5. Spontaneous perforation of bile duct 6. Choledochal cyst 7. Mass (neoplasia, stone) 8. Bile/mucous plug B. Intrahepatic 1. Idiopathic neonatal hepatitis 2. lntrahepatic cholestasis, persistent a. Nonsyndromic paucity of intrahepatic ducts (apparent absence of bile ductules) b. Arteriohepatic dysplasia (Alagille syndrome) c. Byler disease (severe intrahepatic cholestasis with progressive hepatocellular disease) d. Trihydroxycoprostanic acidemia (defective bile acid metabolism and cfiolestasis) e. Zellweger syndrome (cerebrohepatorenal syndrome) 3. Intrahepatic cholestasis, recurrent (syndromic?) a. Familial benign recurrent cholestasis b. Hereditary cholestasis with lymphedema (Aagenaes) 4. Congenital hepatic fibrosis 5. Caroli disease (cystic dilation of intrahepatic ducts) If. Metabolic disorders A. Disorders of amino acid metabolism 1. Tyrosinemia 2. Hypermethioninemia B. Disorders of lipid metabolism 1. Wolman disease 2. Niemann-Pick disease 3. Gaucher disease

errors of metabolism that affect hepatic excretory function, albeit rare, may first be manifest in the neonatal period. For example, selective impairment of a specific step in the hepatic excretory processes may be responsible for the expression of a cholestatic syndrome. Eyssen et al. ~5 and Hanson et al. 16,17 documented the presence of elevated concentrations of trihydroxycoprostanic acid in bile, serum, and urine of children with intrahepatic cholestasis, some in association with Zeltweger (cerebrohepatorenal) syndrome. This suggests that a specific, persistent defect in bile acid metabolism (altered cholic acid synthesis possibly related to specific mitochondrial or peroxisomal dysfunction) may l e a d to impaired bile secretion, either through direct interference by the abnormal toxic compound or through lack of a choleretic compound such as cholic acid. The apparent association of

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Table I. Cont'd C. Disorders of carbohydrate metabolism 1. Galactosemia 2. Fructosemia 3. Glycogenosis IV D. Metabolic disease in which defect is uncharacterized 1. al-Antitrypsin deficiency 2. Cystic fibrosis 3. Idiopathic hypopituitarism 4. Hypothyroidism 5. Neonatal iron storage disease 6. Indian childhood cirrhosis 7. Multiple acyl-CoA dehydrogenation deficiency (glutaric acid type 11) III. Hepatitis A, Infectious 1. Cytomegalovirus 2. Hepatitis B virus (? non-A, non-B virus) 3. Rubella virus 4. Herpesvirus 5. Varicella virus 6. Coxsackie virus 7. ECHO virus 8. Toxoplasmosis 9. Syphilis 10. Tuberculosis 11. Listeriosis B. Toxic 1. Cholestasis associated with parenteral nutrition 2. Sepsis with possible endotoxemia (urinary tract infection, gastroenteritis) IV. Genetic/chromosomal A. Trisomy E B. Down syndrome C. Donahue syndrome (leprechaunism) V. Miscellaneous A. Histiocytosis X B. Shock C. Intestinal obstruction

bile duct paucity, a structural alteration, with an inherited abnormality of bile acid metabolism may allow study of the role of bile acid formation and excretion in the genesis and development of the interlobular bile ducts. An example of an inborn aberration of hepatic excretory function may be what is called microfilament dysfunction. The contractile proteins, which comprise the cytoskeleton of the hepatocyte (microfilaments/microtubules), seem to be involved in bile acid transport and the generation of bile flow. Weber et alY have described 14 North American Indian children with a severe form of familial cholestasis a n d cirrhosis in whom the ultrastructural abnormalities (bile canalicuN~~dilation, prominent pericanalicular filamentous web) were similar to the changes of microfilament hyperplasia noted by Phillips et al. 19 in phalloidin-induced microfilament dysfunction. Whether the altered ultra-

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structural features are a primary inborn error or are secondary to the specific injury is unknown. DIFFERENTIAL CHOLESTASIS

DIAGNOSIS

OF

The list of specific causes of prolonged conjugated hyperbilirubinemia is long and diverse (Table I). However, the clinical presentation in most instances is characteristic (jaundice, dark urine, light stools, hepatomegaly) and is caused by decreased bile flow; there may also be a variable degree of dysfunction in hepatic synthesis and hepatocellular necrosis. The early detection of specific infectious diseases, intoxications, and disorders of amino acid, lipid, or carbohydrate metabolism is important, because in many instances cholestasis attributable to these factors is treatable and reversible. Patients with homozygous a~-antitrypsin deficiency and cystic fibrosis may have hepatobiliary disease or develop one of the consequences of cholestasis such as a coagulopathy with severe hemorrhagic disease. In one series,2~ eight of 67 children with liver disease associated with a~-antitrypsin deficiency had bleeding, and in two infants serious cerebral hemorrhage occurred. Endocrine disorders (hypopituitarism or hypothyroidism) may also be associated with cholestasis. These observations emphasize the importance of hormonal influences on the development and modulation of hepatic excretory function. Relative incidence of the various forms of infantile obstructive eholangiopathy. Despite the long and heterogeneous list of specific diseases that may cause cholestasis during the neonatal period, extensive evaluation leads to a diagnosis of either biliary atresia or neonatal hepatitis in approximately 70% to 80% of infants. These terms are only descriptive and do not imply a specific cause or entity; a uniform definition of terms is required. The major confusion relates to the neonatal hepatitis syndrome. This term has various connotations and should be subdivided to designate hepatitis in a neonate, namely, infection with a specific virus, such as hepatitis B virus or cytomegalovirus, which accounts for only a small percentage of cases; intrahepatic cholestasis, as in the various forms to be discussed; and neonatal hepatitis, which implies an idiopathic process and accounts for the majority of cases. The cause of cholestasis in neonatal hepatitis is undetermined; certain of these patients may prove to have a currently undescribed metabolic or infectious disease. For example, a~-antitrypsin deficiency is now well delineated; cholestasis associated with at-antitrypsin deficiency, formerly included in the idiopathiqcategory, is now clearly separable. Future investigation may permit other discrete diagnoses. In our series of 65 patients with neonatal cholestasis, 19 had extrahepatic biliary atresia, 17 had idiopathic neona-

tal hepatitis, and four were found to have neonatal cholestasis associated with al-antitrypsin deficiency2t; the relative incidence of al-antitrypsin deficiency was unexpectedly lower than in other series. Twelve children had various forms of intrahepatic cholestasis, such as Alagille and Byler syndromes. Other series have also emphasized that the two seemingly disparate entities, idiopathic neonatal hepatitis and biliary atresia, comprise the bulk of the cases?2. 23 Idiopathic obstructive cholangiopathy has been applied to this spectrum of diseases that includes cases of predominant hepatocellular injury, predominant extrahepatic biliary tract injury, as well as intermediate gradations. Landing 24 coined this phrase to encompass in a simple, hypothetical unifying overview the entities of neonatal hepatitis, extrahepatic biliary atresia, and possibly some instances of intrahepatic cholestasis. Neonatal obstructive cholangiopathy may be viewed as a continuum in which each entity is a manifestation or outcome of a single basic underlying disease process. The theory implies that an initial insult leads to inflammation at any level of the hepatobiliary tract, and the end result represents the sequela of a stable or continuing inflammatory process at the primary site of injury, the hepatocytes or bile ducts. The presumed interrelationship has been further strengthened by an apparent postnatal evolution, suggested by reports of patients initially shown to have neonatal hepatitis with a patent biliary system who were subsequently found to have biliary atresia. The theory remains unproved and does not account for all features, such as inheritance patterns. There are, however, sufficient overlapping characteristics toallow perpetuation of the concept, which can serve as a basis for future study. The initial insult and the sustaining mechanisms remain undefined. Viral infection seems to be a likely initial insult, but no specific viral agent has been consistently associated with neonatal obstructive cholangiopathy. Intensive search for evidence of organisms such as hepatitis B virus in tissue or serologic evidence for infection in these patients has been unrewarding. There is, however, a striking similarity between the changes induced by reovirus t y p e 3 infection in weanling mice (hepatitis with biliary tract inflammation) and the progressive postnatal fibrotic obliteration of the extrahepatic bile ducts and liver cell injury noted in biliary atresia in humans? 5 It is possible that reovirus type 3 infection serves as the initial insult in the sequence of events resulting in infantile obstructive cholangiopathy. Infants with biliary atresia have been examined for serologic evidence of reovirus type 3 infection. A murinefibroblast tissue culture line infected with reovirus type 3 was used as the antigen in an indirect immunofluorescent antibody technique for assay of serum. The assay distinguished the infants with biliary atresia from the control

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Neonatal eholestasis

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group and from the group of infants with hepatobiliary disease from other causes. Sixty-eight percent of the patients with biliary atresia had an IFA-positive response. 2S Preliminary studies of infants with neonatal hepatitis show a similarly high positive incidence, suggesting that reovirus type 3 is involved in the pathogenesis of these diseases.26 Confirmation of the putative causative role of this specific virus will require either isolation or identification of the infectious agent or detection of viral antigens and nucleic acid in affected tissue. 27 The observation of immunoglobulin deposits in 33% of 128 biliary remnants removed from patients with extrahepatic biliary atresia suggests that immunologic mechanisms, perhaps in conjunction with viral-induced injury, may perpetuate the inflammation and fibrosis.2s

Table II. Initial workup for suspected cholestasis

THE PROBLEM CHOLESTASIS

megalovirus-induced obliterative cholangitis is a precursor of liver dysfunction associated with paucity of intrahepatic bile ducts? ~ However, initiating factors and the mechanisms of perpetuation remain unknown.

OF INTRAHEPATIC

A heterogeneous subset of cholestatic diseases, characterized by intrahepatic cholestasis with or without bile duct paucity, must be further delineated from neonatal hepatitis and biliary atresia (Table I). These may represent specific syndromes with different prognostic implications. For example, arteriohepatic dysplasia (Alagille syndrome) is characterized by the presence of a decreased number of interlobular ducts. 29 Extrahepatic anomalies, which may be expressed in varying degrees and are possibly nonspecific, include unusual facies (broad forehead, eyes that are deeply set and widely spaced, and a pointed chin), vertebral defects (butterfly vertebrae, hemivertebrae, or a decrease in the interpeduncular distance), cardiovascular abnormalites (peripheral pulmonic stenosis), short stature, and posterior embryotoxon? ~ These diseases generally have a relatively benign prognosis but are included because they often are diagnosed in the neonatal period and might be considered to be either biliary atresia (ductular hypoplasia) or neonatal hepatitis. Intrahepatic cholestasis may represent a further experiment of nature; therefore, detailed study, especially of the seemingly homogeneous varieties, may lead to the identification of specific defects in hepatic excretory function. Bile duct hypoplasia or bile duct paucity implies that within the portal triad there is an absence or marked reduction in the number of interlobular bile ducts despite the presence of normal sized branches of the portal venule and hepatic arteriole. It is uncertain whether this represents a congenital absence, partial failure to form, atrophy, or progressive disappearance. Data from several inyestigators support the latter sequence, because segmental destructive changes or progressive decrease in the number of bile ducts per portal tract on serial biopsies has been documented. Several authors have suggested that cyto-

1. Fractionated serum bilirubin and serum bile acid determinations 2. Index of hepatic synthetic function (prothrombin time) 3. Stool color 4. Cultures (blood, urine, spinal fluid) 5. HB~Ag, TORCH, and VDRL titers 6. al-Antitrypsin phenotype 7. Metabolic screen (urine/serum amino acids, urine reducing substances) 8. Thyroxine and thyroid-stimulating hormone 9. Sweat chloride test 10. Ultrasound 11. Duodenal intubation for bilirubin content 12. Hepatobiliary scintigraphy 13. Liver biopsy

MANAGEMENT CHOLESTASIS

OF THE INFANT WITH

The goals in management of the newborn infant with jaundice follow. Prompt identification of cholestasis is imperative because, as opposed to unconjugated hyperbilirubinemia, this condition is never benign. Therefore, differentiation from physiologic or breast-milk jaundice is the first goal. Early recognition of specific, treatable primary causes of cholestasis is the next goal. Biliary atresia must then be differentiated from neonatal hepatitis, because the prognosis and management of these clinical entities differ significantly. Surgical relief of cholestasis (hepatoportoenterostomy for biliary atresia or drainage of a choledochal cyst) may be attempted in the appropriate patient. In the majority of cases, the challenge is to deal with the consequences of cholestasis and offer nonspecific treatment. Such nonspecific treatment may be critical for ultimate survival and quality of life. 32

Evaluation of the infant with protracted conjugated hyperbilirubinemia. A significant delay in diagnosis or treatment can be tragic if jaundice in an infant is erroneously attributed to physiologic hyperbilirubinemia or to breast-feeding, both of which cause an elevation of predominantly unconjugated (usually >80%) bilirubin. Cholestasis should be considered present in a patient with hyperbilirubinemia if the conjugated (direct reacting) fraction comprises more than approximately 20% of the total. Early in the e~,aluation of the infant with cholestasis, a few precautions should be exercisedf~Hypoprothrombinemia may be present regardless of the cause; therefore, administration of vitamin K to any patient with cholestasis

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Fig. 2. Biliary atresia. Bile duct proliferation is evident in fibrotic portal areas. Hepatic architecture is fairly well preserved outside the portal area. Bile plugs are also evident (arrows). (A, Original magnification )<60; B, •

may prevent catastrophic spontaneous bleeding, such as intracranial hemorrhage. The potentially devastating but treatable illnesses include sepsis, endocrine disorders, and nutritional hepatotoxicity attributable to metabolic disease, such as galactosemia. The institution of appropriate treatment (antibiotics or a galactose-free diet) may prevent further damage. The definitive detection of these specific metabolic, infectious, or endocrine diseases is relatively straightforward. However, the overlap of the diseases classified as idiopathic obstructive chotangiopathy presents a more difficult problem. No single test is entirely satisfactory; therefore, complex, multifaceted schemata utilizing various historical and clinical features have been suggested. Clinical features may aid in the discrimination. For undefined reasons, neonatal hepatitis appears to be more common in boys (up to 70%), 33 especially in those born prematurely or of low birth weight; there is a familial incidence of approximately 15% to 20%. Extrahepatic biliary atresia, in contrast, occurs more commonly in girls, and no well-documented familial cases have been reported. There is an increased incidence of the polysplenia syndrome (abdominal heterotaxia/malrotation, levocardia) and intra-abdominal vascular anomalies in patients with biliary atresia. 34 Numerous diagnostic algorithms utilizing biochemical features have been proposed in an attempt to select those infants who are surgical candidates and to avoid unnecessary surgery. Percutaneous transhepatic cholangiography or endoscopic retrograde cholangiography, which are used

extensively in evaluation of adults with cholestatic disease, 35 have rarely been of value in these children. Ultrasonography is of limited value, although it may detect dilation of the biliary tract in a patient with a choledochal cyst. The tests or procedures that we have found to be of specific value are listed in Table II. A few deserve comment regarding false results that may occur during attempts to rule out infectious and metabolic diseases. Assessment of urine reducing substances and of urine and serum amino acids can be of help if placed in the proper clinical context. 36F o r example, an infant with cholestasis associated with galactosemia may not excrete the offending sugar in the urine after abstention from a galactosecontaining formula or if the infant has been vomiting. However, the diagnosis can be reliably confirmed by red cell assay for galactose-l-phosphate uridyl transferase activity, provided the infant has not recently received a blood transfusion. The parents of a galactosemic infant are obligate heterozygotes and will have intermediate levels of this enzyme. Elevated serum concentrations of tyrosine and methionine may occur in neonatal liver disease of various causes and do not necessarily indicate a specific metabolic disease such as tyrosinemia. The detection of unique metabolites, which reflect an altered pathway of tyrosine degradation, provides much more reliable criteria for the diagnosis of tryosinemia. 37 The most common metabolic cause of neonatal cholestasis in most series, c~-antitrypsin deficiency, may be best excluded by determination of the ~-antitrypsin phenotype. 3~ The serum

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177

Fig. 3. Neonatal hepatitis. Lobular disarray and inflammatory cells within portal area (arrow) are demonstrated. Higher magnification shows multinucleated giant cells (g) adjacent to portal area (p.) (A, Original magnification X80; B,

x4oo.)

concentration alone may not accurately reflect the deficiency state. A very valuable clinical clue is provided by the presence of acholic stools; the consistent absence of pigment suggests biliary obstruction. This is not specific for biliary atresia, because patients with severe neonatal hepatitis may undergo a phase in which bile excretion is severely retarded as a result of intrahepatic disease. Conversely, the consistent presence of pigmented stools rules out biliary atresia. A simple yet reliable maneuver is to obtain duodenal fluid to assess the bilirubin content. 39 If bile-stained fluid is collected, biliary atresia is virtually excluded; in one Series,4~none of i 51 patients with extrahepatic biliary atresia had bilirubin pigment in duodenal fluid. Although some patients with neonatal hepatitis may have absence of bile-stained fluid, in the majority it will be present. The use of new hepatobiliary scintigraphic agents, such as iminodiacetic acid analogs, has been helpful to some investigators? ~,42 In biliary atresia, hepatocyte function is usually intact early in the disease; therefore, uptake of the agent is unimpaired, but excretion into the intestine is absent. By contrast, in neonatal hepatitis uptake is sluggish or impaired, but excretion into the bile and intestine eventually occurs. Oral administration of phenobarbital (5 mg/kg/day) for 5 days prior to the study may enhance biliary excretion of the isotope and therefore increase the discriminatory value. 42.43 The most reliable evidence in our experience and that of

many otherS is obtained by liver biopsy.2t,23,44,45 In most cases this can be performed using the Menghini technique of percutaneous aspiration with local anesthesia. Interpretation by an experienced pathologist will provide the correct diagnosis in 90% to 95% of cases and will avoid unnecessary surgery in patients with intrahepatic disease. The classic histologic features of biliary atresia are bile ductular proliferation, bile plugs, and portal or perilobular fibrosis and edema; the basic hepatic lobular architecture remains intact (Fig. 2). This contrasts with neonatal hepatitis, in which severe hepatocellular disease may be accompanied by marked infiltration with inflammatory cells and focal hepatocellular necrosis (Fig. 3). Bile ductules show little or no alteration in neonatal hepatitis. Giant cell transformation is found in a high percentage of infants with either condition and has no diagnostic specificity. Alagille has used several of these clinical and histologic features as discriminant variables to differentiate biiiary atresia from neonatal hepatitis in patients studied before the age of 3 months. 44 The following features occurred significantly more frequently in infants with neonatal hepatitis than in those with extrahepatic biliary atresia: male gender (66% vs 45%); low birth weight (mean 2680 vs 3230 gm), the presdnce of other congenital anomalies (32% vs 17%), onset of jaundice (mean 23 vs 11 days of age), onset of acholic stools (mean 30 vs 16 days), white stools within 10 days after admission (26% vs 79%), and enlarged liver with a firm or hard consistency (53% vs 87%). Bile

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The Journal of Pediatrics February 1985

right hepatic duct

~

"~,

common

hepatic

i

'

~

left hepatic d u c t

left

hi~patic a r t e r y

duct

Fig. 4. Extrahepatic biliary atresia. Operative approach. Transected fibrous cord represents obliterated common hepatic duct. At porta hepatis, minute channels (black dots) are visible in right and left hepatic duct remnants. (From Altman RP: Pediatr Ann 6:87, 1977.) Presence of biliary epithelium in resected porta hepatis may be confirmed by examination of frozen sections (Fig. 5).

ductular proliferation was absent in 70% of the patients with neonatal hepatitis, compared with only 14% of those with extrahepatic biliary atresia. Discriminant analysis using these variables permitted accurate distinction between intrahepatic and extrahepatic cholestasis in 85% of the patients tested. In those patients thought to have biliary atresia on the basis of these clinical, biochemical, and histologic features, exploratory laparotomy with intraoperative cholangiography (to document the presence and site. of obstruction) may provide the definitive diagnosis and properly direct attempts at drainage. The presence of biliary epithelium and the size of residual ducts can be evaluated in frozen sections of the transected porta hepatis. This approach is not without pitfalls, as pointed out in several reports 33'43.46and by unpublished experience, which suggest that caution be exercised in interpretation of certain studies. Delayed accumulation of radioactivity during scintigraphy suggested intrahepatic disease in four patients described by Markowitz et al.46; however, in view of the lack of excretion into the intestine, surgical exploration was performed. Intraoperative cholangiography with clamping of the distal common bile duct did not demonstrate the proximal intrahepatic biliary radicals; therefore, hepatoportoenterostomy was performed. Postoperatively

there was inadequate drainage in all patients with cholangitis, cirrhosis in two, and death from hepatic failure in one infant?6.47 A subsequent histologic and clinical diagnosis of arteriohepaticdysplasia was made; however, the occurrence of the progressive hepatic disease demonstrates that portoenterostomy had severely altered the course of this relatively benign disorder. During cholangiography, an absence of retrograde flow into the proximal intrahepatic ducts does not-exclude the presence of a patent, albeit hypoplastic, extrahepatic biliary duct system in a patient with intrahepatic disease. Therefore, in view of the highly variable results attained in patients who have undergone such radical operative procedures, portoenterostomy should be reserved for highly selected cases as discussed below. Surgical management of biliary atresia. The anatomy of the abnormal extrahepatic bile ducts may vary markedly. So-called correctable lesions are those in which there is distal atresia along with a patent portion of the extrahepatic duct up to the porta hepatis, thereby allowing direct drainage. Unfortunately, the most commonly encountered lesion is obstruction of the ducts at or above the porta hepatis; this occurs in 75% to 85% of cases of extrahepatic biliary atresia and presents an apparently noncorrectable type of atresia. However, cure rates are highly variable

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Fig. 5. A, Section from patient, currently 8 years of age, in whom bile flow was established in postoperative period. Duct is Of relatively large caliber (~ 400/~m diameter); epithelium has been denuded, and wall consists of granulation tissue with chronic inflammation. (H and E; X40; bar - 1,000#m.) B, Minute bile ducts (<50 #m), which were unable to sustain bile flow. Patient died at 7 months of age. (H and E; :480; bar = 100 #m.)

despite the rate of pOtential operability of approximately 15% to 25%. 33`48Thirty percent of infants thought to have an uncorrectable defect at initial laparotomy have later been found to have a usable dilated hepatic duct. 33 A radical surgical approach was based on the observation of Kasai that minute bile duct remnants or residual channels are present in the fibrous tissue near the porta hepatis; these channels are often in continuity with the intrahepatic ductal system38 Therefore, dissection into the liver parenchyma to a depth of 2 to 4 mm at this site should allow drainage. It was postulated that if flow is not rapidly established in these ducts, progressive obliteration will

ensue. This led to attempts by Kasai and others to establish biliary drainage by excision of the obliterated extrahepatic ducts (Figs. 4 and 5) and apposition of the resected surface of the porta hepatis to the bowel mucosa (hepatoportoenterostomy)48,49 (Fig. 6). Many of the operative variations include creation of an abdominal stoma. P R O G N O S I S A~FTE R HEPATOPORTOENTEROSTOlfr Without doubt, certain patients with biliary atresia derive long-term benefit from hepatoportoenterostomy, in

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Fig. 6. Kasai procedure, demonstrating Roux-en-Y portoenterostomy. (From Altman RP: Pediatr Ann 6:87, 1977.)

the majority, a variable degree of hepatic dysfunction persists. However, there is short-term benefit, because growth to a size sufficient for transplantation is often achievable. The highly variable prognosis for patients with biliary atresia after hepatoportoenterostomy is directly related to several factors. The age at operation is crucial; bile flow has been established in approximately 90% of infants younger than 2 months of age. 48 The success rate drops rapidly, to under 20%, in those older than 90 days at the time of operation. The size of the ducts visualized in tissue from the porta hepatis seems to be important, because microscopic patency should determine postoperative bile flow; however, this concept is not universally accepted.32 ,5~ Chandra and Altman 53 examined the resected, fibrotic intrahepatic biliary system in 65 patients who had undergone hepatoportoenterostomy. Patients with lumens >_ 150 #m had an excellent chance o f achieving postoperative bile flow. However, if the size of the lumen (proximal margin) was <150 /~m, counting single or multiple ductal structures, the rate of success declined. For those patients with no identifiable epithelial-lined structures in fibrous tissue, the rate was low. The experience and operative technique of the surgeon is also a determinant. The rate of progression of the liver disease may b e the overall limiting factor; a nearly universal finding is the

The Journal of Pediatrics February 1985

presence of intrahepatic disease. The persistent inflammatory process in the intrahepatic biliary tree may explain why results expected for correction of a static lesion are not obtained; this feature may partially account for the poor results and for the development of portal hypertension. Recent studies have reemphasized the dynamic pathology of the intrahePatic ducts. Ito et al. 54 correlated survival with intrahepatic bile ductular epithelial cell injury. The continuing nature of the disease process may be caused by persistence of an infectious agent (possibly reovirus type 3), immunologically mediated injury, or the presence of an undefined metabolic aberration. The prevention of secondary postoperative complications has been frequently cited as a major prognostic determinant; bacterial cholangitis, which is a constant threat, can lead to reobstruction. Kobayashi et al. 55 noted that 47% of 17 patients with successfully repaired extrahepatic biliary atresia developed cholangitis. These patients, who previously had good bile excretion, were noted to have repeated episodes of fever, increased jaundice, leukocytosis, and evidence of contamination with intestinal flora. Altman 49 has emphasized the potential value of reoperation in patients with refractory cholangitis; in many cases debridement or revision of the scarred area is associated with the establishment of bile flow. MEDICAL MANAGEMENT CHOLESTASIS

OF CHRONIC

The clinical consequences of prolonged cholestasis are well known and are attributable directly or indirectly to diminished bile flow: (1) retention by the liver of substances normally excreted in bile (bile acids, bilirubin, cholesterol, and trace elements) with subsequent regurgitation into serum and tissue; (2) decreased delivery of bile acids to the proximal intestine with decreased intraluminal bile acid concentrations and malabsorption of fat and fat-soluble vitamins; and (3) progressive liver damage with biliary cirrhosis, portal hypertension, and liver failure. Cholestasis, liver damage, and malnutrition may interact to alter the metabolism of hormones, somatomedins, or other factors required for growth, and thus result in marked growth failure. In patients with neonatal hepatitis, intrahepatic cholestasis, or biliary atresia in whom surgery is unsuccessful, management becomes an effort to minimize growth failure and to reduce discomfort. The limiting factors remain the residual functional capacity of the liver and the rate of progression of the liver disease. We have listed our recommendations for management of cholestasis (Table III); these are somewhat empiric, and careful monitoring should serve as the most reliable guide. The major complications are malabsorption and malnu-

Volume 106 Number 2

Neonatal cholestasis

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Table Ill. Suggested medical management of consequences of persistent cholestasis

Effect Malnutrition Malabsorption of dietary long-chain triglyceride Fat-soluble vitamin deficiency A (night blindness, thick skin) E (neuromuscular degeneration) D (metabolic bone disease) K (hypopr0thrombinemia) Micronutrient deficiency Deficiency of water-soluble vitamins Retention of biliary constituents Bile acids and cholesterol (itch/xanthomas) Trace elements, such as copper (? hepatotoxicity) Progressive liver disease Portal hypertension (variceal bleed, ascites, hypersplenism) End-stage liver disease

]

Management Replace with dietary formula or supplement containing medium-chain triglyceride Adequate protein (vegetable protein) Adequate calories (complex starch) Replace with 10,000 to 15,000 IU/day as Aquasol A Replace with 50 to 400 IU/day as oral a-tocopherol (may require parenteral administration) Replace with 5000 to 8000 IU/day vitamin Dz or 3 to 5 gg/kg/day 25-hydroxycholecalciferol Replace with 2.5 to 5.0 mg every other day as water-soluble derivative, of menadione Calcium/phosphate/zinc supplementation Supplement with twice recommended daily allowance Choleretics (phenobarbital 5 to 10 mg/kg/day) Bile acid binders (cholestyramine 8 to 16 gm/day) ? Avoid copper-enriched food ? Chelating agents Interim management (control bleeding, salt restriction) Transplantation

trition from ineffective intraluminal long-chain triglyceride lipolysis and absorption. Therefore, the use of mediumchain triglycerides may be beneficial. Fat-soluble vitamins require solubilization by bile acids into mixed micelles prior to intestinal absorption; therefore, deficiency may occur during chronic cholestasis and be associated with significant symptoms, most prominently rickets caused by vitamin D deficiency and neuromuscular disease associated with vitamin E deficiency?6-58 Malabsorption of these vitamins may be exacerbated by coadministration of cholestyramine. The marked impairment of vitamin E absorption may not be compensated by even massive orally administered doses of the vitamin. 57 Chronic deficiency of vitamin E (o~-tocopherol) results in the development of a progressive neuromuscular syndrome composed of areflexia, cerebellar ataxia, posterior column dysfunction, and peripheral neuropathy? 6,57 The diagnosis of vitamin E deficiency in children with chronic cholestasis has been based on low serum levels. A more reliable index may be the ratio of serum vitamin E to total serum lipids (sum of fasting serum cholesterol, triglyceride, and phospholipids; normal, >0.6 mg/gm in children, >0.8 mg/gm in adults)? 9 Elevated lipid values allow vitamin E, which circulates in the plasma lipoprotein fraction, to partition into this nonpolar phase and falsely raise the serum vitamin E concentration, often into the normal range. Recent success has emphasized the need for early attempts at repletion by

either large doses orally (50 to 200 I U / k g / d a y c~-tocopherot) or the use of parenterally administered vitamin E in selected patients? 7,~9 The parenteral form of vitamin E (DL-a-tocopherol; Hoffman-LaRoche) is currently an investigational drug. Troublesome pruritus and xanthomas may cause significant morbidity. The goals in management are to increase the conversion of cholesterol to bile acids and to enhance the elimination of retained bile acids. This requires patent bile ducts; compounds such as phenobarbital and cholestyramine will work only if there i s an adequate drainage system to allow bile acids to reach the gut lumen. It is theoretically possible that interruption of the itch may be accomplished with carbamazepine or other agents affecting pain fibers; however, no data are available to corroborate this approach. The ultimate therapy for patients with liver failure caused by neonatal cholestasis may be orthotopic liver transplantation. The major indication for liver transplantation in pediatric patients is biliary atresia, which accounts for approximately 50% of all recipients. The high success rates (60% to 70%) reported in children, the result of excellent pre-, lntra-, and postoperative care as well as the use of cyclosporine, have been encouraging. The initial human orthotopic liver transplantation was performed in I963. ~~ Since then, more than 500 operations have been performed in the United States and

18 2

Balistreri

Western Europe. In June 1983, the participants at a Consensus Development Conference on Liver Transplantation held by the National Institutes of Health concluded that the operation is technically feasible and that liver transplantation offers an alternative therapeutic approach that may prolong life in certain patients with severe liver disease. 62Although the success of biliary enteric anastomosis in patients with extrahepatic biliary atresia cannot be predicted, we believe it remains the most reasonable initial therapy. Liver transplantation should be delayed as long as possible to permit maximal growth. However, repeated attempts at revision of the hepatoportoenterostomy or portosystemic shunting seem to render eventual transplantation surgery more difficult and more dangerous. In that situation, liver transplantation should be strongly considered. P R O G N O S I S FOR P A T I E N T S W I T H INTRAHEPATIC DISEASE An analysis of subsets, such as a~-antitrypsin deficiency, points out the variability in severity and prognosis in patients with any form of intrahepatic disease. Sveger63,64 has emphasized that only 11% of children with the PiZ phenotype have overt liver disease, despite a high incidence of biochemical abnormalities. Psacharopoulos et ai. 2~ followed 74 children with chronic liver disease associated with al-antitrypsin deficiency and noted that by 17 years of age 27% had died, an additional 27% had established cirrhosis, 26% had persisting liver disease, and only 20% had documented clinical and biochemical recovery. This disease seems to breed true, because the pattern of liver disease in siblings with the deficiency was similar; however, environmental factors may exert an influence. The outcome in infants with neonatal hepatitis is also highly variable. Of the sporadic cases reported by Danks et al., 65 approximately 60% recovered, 10% had persisting fibrosis or inflammation, 2% had cirrhosis, and 30% had died. This outcome differed from that in familial cases, in which there was a much more severe outcome: 30% recovered, 10% developed chronic liver disease with cirrhosis, and 60% died. A similar phenomenon has been noted by others. 21,32 The heterogeneous nature of other diseases manifested as intrahepatic cholestasis, with or without bile duct paucity, precludes an accurate statement regarding overall prognosis. There are certain progressive, fatal, familial forms such as that seen in the Byler syndromer 6 However, in patients with syndromic paucity of ducts (arteriohepatic dysplasia syndrome), the prognosis is much more favorable. 29,61,68 The genetic basis for this disease is only partially defined; however, it appears that there are mild forms with varying clinical features.

The Journal of Pediatrics February 1985

SUMMATION The spectrum of diseases causing neonatal cholestasis presents intriguing problems for future investigation. There are many causes, and the eventual outcome of the specific entity has unique individual features, despite the wide areas of overlap. For example, extrahepatic biliary atresia may be the result of the sporadic occurrence of a virus-induced, progressive obliteration of the extrahepatic bile ducts with some degree o f intrahepatic bile duct injury. This same sequence of viral infection with persisting injury may account for sporadic (nonfamilial) cases of neonatal hepatitis, as suggested by the Landing hypothesis. Conversely, the familial forms of cholestasis, either neonatal hepatitis or instances of intrahepatic cholestasis, are most likely genetic diseases that represent specific defects in the hepatic excretory process or in the bile secretory apparatus. The persistent nature of these presumed enzymatic or structural defects may explain the less favorable prognosis. Elucidation of the nature of these inborn errors of liver function may allow a better understanding of biliary physiology, and improved therapy. I thank Dr. Kevin E. Bove for assistance with the histologic sections; Dr. Frederick J. Suchy for reviewingthe manuscript; and Ms. Pamela A. Hyland for assistance in preparing the manuscript. REFERENCES 1, Balistreri WF, Heubi JE, Suchy FJ: Immaturity of the enterohepatie circulation in early life: Factors predisposingto "physiologic" maldigestion and cholestasis. J Pediatr Gastroenterol Nutr 2:346, 1983. 2. Suchy FJ, Balistreri WF, Heubi JE, Searcy JE, Levin RS: Physiologic cholestasis: Elevation of the primary serum bile acid concentrations in normal infants. Gastroenterology 80:1037, 1981. 3. Balistreri WF: Age-related alterations in hepatic structure and function. In Children are different, ed 3. Columbus, Ohio, 1984, Ross Laboratories. 4. Balistreri WF, Zimmer L, Suchy FJ, et al: Bile salt sulfotransferasc: Alterations during maturation and non-induclbility during substrate ingestion. J Lipid Res 25:228, 1984. 5. Suchy FJ, Courchene SM, Balistreri WF: The developmentof hepatic bile acid conjugation in the rat. Pediatr Res 17:202, 1983. 6. Back P, Walter K: Developmental pattern of bile acid metabolism as revealed by bile acid analysis of meconium. Gastroenterology 78:671, 1980. 7. Strandvik B, Wikstrom SA: Tetrahydroxylated bile acids in healthy human newborns. Eur J Clin Invest 12:301, 1982. 8. Balistreri WF, Suchy FJ, Farrell MK, Heubi JE: Pathologic versus physiologiccholestasis: Elevated serum concentration of a secondary bile acid in the presence of hepatobiliary disease. J PEDIATR98:399, 198 1. 9. Utili R, Abernathy C, Zimmerman H: Inhibition of Na §

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Erratum. Please note the following corrections to the article " F o u r siblings with malformations after exposure to phenytoin and primidone" (Krauss et al: 105:750, 1984). On page 752, column 1, line 1 should read " . . . decrease in skull breadth, a n d maxillary hypoplasia (Fig. 1, Table II)." On page 754, column 2, p a r a g r a p h 2, line 8 should read " . . . abnormalities, 27 which are associated . . . . "