The guidelines were then reviewed by primary care physicians in community and academic practices. In addition, the guidelines were distributed to the NASPGHAN membership for review and comment and were officially endorsed by the NASPGHAN Executive Council. This document represents the official recommendations of NASPHGAN on the evaluation of cholestatic jaundice of the infant. The American Academy of Pediatrics has also endorsed these recommendations. This review and 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.
The initial recognition and evaluation of any infant with possible cholestasis depends upon physicians and other providers of medical care to infants. The age limits of 2 weeks to 8 weeks of age used in this guideline were selected because they represent times when primary care providers typically examine healthy infants. As the evaluation proceeds, the tests to accurately diagnose cholestasis fall increasingly in the province of the referral center and pediatric gastroenterologist. Different care models or differing relationships between primary physicians and referral centers may alter the point at which the responsibility for the evaluation shifts from primary care to specialist. The goal remains the early detection and efficient diagnostic evaluation of cholestasis in infants.
The report of pale stools by the parent or observation of clay colored stool by the physician raises the suspicion of cholestasis. In one study of 3,629 infants, 4 passed pale stools during the first 4 weeks of life, none more than three times. None of these infants had liver disease. The high specificity of persistent pale stools means that this finding almost certainly indicates disease when it is present. However, infants with biliary atresia have been noted to have pigmented stools at presentation, and stool color is variable in other conditions causing cholestasis (20). Parents do not appear to be reliable observers of stool color: even when the specific question “What color is your baby’s stool?” was added to a booklet received by all parents for well care, the average age for definitive care for infants with biliary atresia was not improved (4). A scoring card displaying color photographs of normal and abnormal stools modestly improved case finding in a subsequent program (21).
Dark urine is also a nonspecific indicator of increased conjugated bilirubin. No studies could be found that addressed the utility of this sign for case finding. Literature review did not identify any studies that defined specificity or sensitivity for the findings of jaundice, pale stools, or dark urine in combination. Thus, the clinician must continue to test for cholestasis when these findings are present, despite the low yield. The American Academy of Pediatrics practice parameter on the management of hyperbilirubinemia in the healthy term newborn recommends testing for conjugated hyperbilirubinemia if jaundice is accompanied by dark urine or light stool or if it persists beyond 3 weeks (22).
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 (Table 6) 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.
Bacterial infections, including urinary tract infection, are a well known cause of concomitant conjugated hyperbilirubinemia, probably because of the effect of bacterial endotoxin on bile formation (23,24). Otherwise asymptomatic jaundiced infants may have urinary tract infection, particularly if the onset of jaundice occurs after 8 days of age (25). Jaundice caused by an acute infection resolves when the acute illness has been addressed. Because jaundice is more likely to be related to the underlying illness, rather than primary liver disease, in the acutely ill infant, management is oriented to the underlying acute illness.
Because either conjugated or unconjugated hyperbilirubinemia may be present in a jaundiced infant who does not appear acutely ill, measurement of serum bilirubin that includes both total and direct (conjugated) bilirubin is recommended. The most commonly used laboratory determination (the diazo or van den Bergh method) does not specifically measure conjugated bilirubin but reports direct bilirubin. For methodological reasons, the higher the total bilirubin (even if it is all unconjugated), the higher the reported direct bilirubin (26–28). Measurements of direct bilirubin may vary significantly both within and between laboratories (29–32). The methods used may also influence the measurement of conjugated bilirubin (33–35). A specific measurement of conjugated bilirubin, such as that obtained with the Ektachem system, is optimal. Because canalicular excretion of bilirubin can be rate limiting to overall clearance, infants with high nonconjugated bilirubin may retain some conjugated bilirubin. Therefore, in the presence of elevated total bilirubin, conjugated bilirubin levels are considered abnormal when values greater than 1.0 mg/dL are reported (36). Practitioners whose laboratories use the Ektachem system could use a value of conjugated bilirubin greater than 1.0 to define cholestasis, regardless of total bilirubin. For this guideline, we defined an abnormal direct bilirubin as a value greater than 1.0 mg/dL if the total bilirubin is less than 5 mg/dL, or a value of direct bilirubin that represents more than 20% of the total bilirubin if the total bilirubin is greater than 5 mg/dL. It is important to be aware of the potential for error in these measurements and consult with the laboratory if the measurements are inconsistent with the appearance of the patient. Urine testing has also been used to diagnose cholestasis: assay of sulfated bile acids in urine was found in a single study to distinguish control infants from those with cholestasis, but this test is not generally available (37).
For infants with only unconjugated hyperbilirubin-emia, practitioners can refer to the previously published guideline on management of unconjugated hyperbilirubinemia from the American Academy of Pediatrics (22). If the conjugated serum bilirubin is elevated, cholestasis is present. The further evaluation of an infant with cholestasis is a matter of some urgency. Because biliary atresia is one of the possible causes of cholestasis, the goal of management is to complete the diagnostic evaluation, or at least to exclude biliary atresia, by 45 to 60 days of age. History and physical examination can help guide the diagnostic process for the infant with cholestasis. Some findings on history or physical examination will lead the clinician to other diagnostic possibilities. For example, 3% of infants with severe ABO hemolytic disease have conjugated hyperbilirubinemia that may persist until 2 weeks of age; thus, further observation may suffice for these infants (38). Table 6 describes abnormalities that may be present on history and physical examination and their potential significance. Abnormalities suggestive of a particular disease entity would lead to more focused diagnostic evaluation, rather than further investigation of cholestasis. It is important to evaluate or repeat the newborn screen for galactosemia and hypothyroidism because these conditions can present with conjugated hyperbilirubinemia and require urgent management to prevent serious sequelae (39–42). Keeping in mind that the diagnosis of one disease does not preclude the presence of another, additional evaluation is necessary if the jaundice does not resolve with treatment of these specific conditions.
Consultation with a pediatric gastroenterologist is essential for infants with conjugated hyperbilirubinemia of unknown cause. The nature of this consultation may vary among practice settings. A telephone consultation may be particularly useful for practitioners at some distance from specialty care. Of the tests listed in Box 15 of the algorithm (Fig. 1), which should be ordered and where they should be performed is likely to vary, depending on which of the tests are readily available to the referring physician, and on whether examination of the patient by the specialist will be delayed. If the level of serum alpha-1 antitrypsin is found to be low, Pi typing is indicated. If an obvious extrinsic obstruction (such as choledochal cyst) is present, referral for surgery is warranted. Of the tests listed at this decision point, the ultrasound is the most operator dependent, and thus may be most appropriately performed at the referral center by more experienced personnel. In many practice settings, all of the listed tests would be best obtained by immediate referral of the patient for evaluation by the pediatric gastroenterologist. In the evaluation for infants with possible biliary atresia, it is optimal for an experienced pediatric surgeon to also be involved.
Ultrasonography is useful to identify anatomic abnormalities such as choledochal cyst. The finding of a small or absent gallbladder may suggest extrahepatic biliary atresia, but reported sensitivities as low as 73% indicate that ultrasound cannot be used to rule out this diagnosis. Several reports of high sensitivity and specificity of the “triangular cord” sign on ultrasound suggest that this test may be useful in the diagnosis of extrahepatic biliary atresia.(43–45) Again, this appears to be operator dependent. Despite these limitations, we recommend ultrasonography for the evaluation of the infant with cholestasis of unknown etiology.
Gamma glutamyl transpeptidase (GGT) has been used in the past to distinguish biliary atresia from neonatal hepatitis, but wide variability in levels makes interpretation of test results difficult. Especially in the older infant with cholestasis, a very low GGT level may be useful to exclude obstruction and, in conjunction with an elevated alkaline phosphatase level, suggests genetic and metabolic causes of intracellular cholestasis. The degree of elevation of GGT is not useful in discriminating the etiology of the cholestasis. The evidence supporting the use of ultrasound and GGT is summarized in Table 7.
Once it is established that cholestasis is present, the principal diagnostic concern is the differentiation of hepatocellular from obstructive cholestasis, of disorders of physiology from disorders of anatomy, and of disease that is managed medically from disease that is managed surgically. The tests that have been used to make this differentiation and about which we were able to find at least some evidence regarding their value were percutaneous liver biopsy, hepatobiliary radionuclide scan, and duodenal aspirate. Evidence and citations for the use of these tests are summarized in Table 7.
Most studies of percutaneous liver biopsy are retrospective analyses using as a gold standard the clinical course or surgical or autopsy results. Biopsy interpretation is pathologist dependent, and requires experience that many general pathologists lack. Review of all of the studies of biopsy revealed that 50% to 99% of patients with biliary atresia are correctly identified with biopsy. Biliary atresia is incorrectly suspected from the biopsy in 0% to 46%.
The interpretation of a single liver biopsy in a child with neonatal cholestasis is also limited by the dynamics of disease. Many cholestatic conditions express themselves differently with time. Liver biopsy specimens obtained early in the course of biliary atresia may be indistinguishable from hepatitis (47). In addition to being able to visualize the hepatocanalicular cholestasis and injury, the liver biopsy also can provide disease-specific findings. Examples include PAS-positive granules in alpha-1 antitrypsin deficiency, ductal paucity in Alagille syndrome, necroinflammatory duct lesions in sclerosing cholangitis, and other findings that are relatively specific for metabolic and storage diseases.
The evidence indicates that liver biopsy can be performed safely and expeditiously in young infants and is useful in establishing specific diagnoses (48). The Cholestasis Guideline Committee recommends that a liver biopsy be performed in most infants with undiagnosed cholestasis, to be interpreted by a pathologist with expertise in pediatric liver disease. A percutaneous liver biopsy is recommended before performing a surgical procedure to diagnose biliary atresia. If the biopsy is done early in the course of the disease (before 6 weeks of age), the biopsy may have to be repeated if the results are equivocal.
Injected radioactive material is normally excreted into the intestine within a predictable period of time. Nonvisualization of radioactivity within the intestine (in the scanning field comprising the intestines) 24 hours after injection is considered to be an abnormal result, indicating biliary obstruction or hepatocellular dysfunction. In the studies reviewed, a variety of radiolabeled scintigraphic agents were used, the diagnostic criteria varied greatly, and no blinded comparisons were found between scintigraphy and a gold standard for diagnosis. Although it is thought that the precision of the test can be improved by administering phenobarbital for several days before imaging, no studies are available to confirm or refute this hypothesis. In the available studies, the sensitivity of scintigraphy for the diagnosis of biliary atresia is high; virtually all patients with complete biliary obstruction showed no excretion on scintiscan. A few patients with a negative test (tracer evident in the intestine) later experienced biliary atresia, presumably because of disease evolving from incomplete to complete obstruction. Specificity of scintigraphy for biliary atresia or other obstructive processes is low; many patients without anatomic obstruction will not excrete tracer. Although the high sensitivity for biliary atresia makes this a fairly good single test for detecting disease, it is time consuming and expensive and does have significant false-positive and false-negative results. The Cholestasis Guideline Committee concludes that hepatobiliary scintigraphy generally adds little to the routine evaluation of the cholestatic infant but may be of value if other means for excluding biliary obstruction are not available.
Limited data indicate that duodenal aspirate analysis for bilirubin concentration can identify patients with biliary obstruction with a sensitivity similar to that of scintiscan. In this test, fluid is obtained from the duodenum, either by placing a tube or a string in the duodenum, and analyzed for bilirubin concentration. A positive test for obstruction is one in which the bilirubin concentration of the aspirate is no greater than serum concentration. This would appear to be a low-tech, inexpensive alternative to scintiscan, yet it is not commonly used, probably because it is time and labor intensive, invasive, and inconvenient. The Cholestasis Guideline Committee concludes that the duodenal aspirate test may be useful in situations in which other tests to detect biliary obstruction are not available.
The few reports available to date have studied a very small number of patients, and although the results are encouraging, firm conclusions are not possible. Magnetic resonance cholangiopancreatography (MRCP) requires deep sedation or general anesthesia. Additional technical advancement and clinical experience are necessary before MRCP can be used in the evaluation of cholestatic infants. The Cholestasis Guideline Committee concludes that this test cannot be routinely recommended based on the currently available data.
Endoscopic retrograde cholangiopancreatography (ERCP) is an evolving technology that has been increasingly used in some tertiary referral centers to diagnose the cause of cholestasis in young infants. ERCP involves endoscopic intubation of the biliary (and pancreatic) ducts via the ampulla of Vater with a small tapered catheter and injection of contrast material to facilitate radiologic visualization of the ductal systems. A small pediatric side-viewing duodenoscope has enhanced the capability to perform this procedure in young infants. Most endoscopists prefer to perform this procedure with the patient under general anesthesia.
The data supporting the use of ERCP for the evaluation of the cholestatic infant are sparse. Many of the reports simply document the use of the prototype smaller side-viewing instrument for these patients. Operators report mixed success with the procedure to distinguish biliary atresia from neonatal hepatitis and other forms of nonoperative cholestasis. Most tertiary centers use ERCP to sort as surgical or nonsurgical cases that remain equivocal after liver biopsy. No controlled studies have been conducted to compare endoscopic techniques. In larger studies, sensitivity and specificity are excellent, but failed cannulation and/or visualization are reported in more than 10%. Patient populations vary from young infants to older infants (before or after 60 to 90 days of age). No controlled study has been done to demonstrate that ERCP will alter the final diagnosis. A cost-benefit analysis of ERCP has not been performed, but it is possible that the procedure could obviate the need for surgical exploration in some infants. ERCP in pediatric patients has been recommended only at facilities with appropriate support staff and specialists with expertise in this procedure in young infants (49).
The Cholestasis Guideline Committee concludes that ERCP is not frequently used because of the cost of instrumentation and the need for technical expertise. The usefulness of ERCP appears to be center and operator dependent. Clinicians with the appropriate expertise and instrumentation will find the test a useful adjunct in the evaluation of the difficult-to-diagnose cause of cholestasis in an infant in whom laparotomy is being contemplated. The Committee recommends that a liver biopsy be obtained before subjecting an infant to ERCP. Under selected circumstances, ERCP can clarify the cause of neonatal cholestasis and obviate the need for laparotomy. ERCP can be recommended in selected cases at facilities with appropriate support staff and specialists with expertise in this procedure in young infants.
This test is no longer widely available; the few studies on this subject are of poor quality and suggest poor sensitivity and specificity for differentiating biliary atresia from neonatal hepatitis. The Cholestasis Guideline Committee recommends that this test not be performed.
The rapid and effective diagnosis of the cause of cholestasis in an infant is challenging. The initial detection of these infants remains in the domain of the primary care provider and depends on the recognition of jaundice past the age of 2 weeks or recognition of abnormal stool or urine color. Laboratory testing for cholestasis should include direct (conjugated) bilirubin. A direct bilirubin value greater than 1.0 mg/dL if the total bilirubin is less than 5 mg/dL or a direct bilirubin more than 20% of the total bilirubin if the total bilirubin is greater than 5 mg/dL is considered abnormal. The relative rarity of cholestatic jaundice in contrast to unconjugated hyperbilirubinemia in this age range dictates that many jaundiced infants will be tested to find a few with elevated direct bilirubin. It is recommended that primary care providers continue to screen for cholestasis, despite its rarity, because of the gravity of the consequences of missed diagnosis.
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.
Identification of cholestasis warrants a prompt effort to accurately diagnose the cause. In an ill appearing infant, the primary cause of the acute problem should be sought and treated. Cholestasis that does not resolve with resolution of the acute problem requires thorough evaluation. In a well appearing infant, cholestasis should be evaluated without delay because this condition has etiologies that are both serious and treatable. Patients with extrahepatic biliary atresia often appear well at initial presentation, and in these patients there is evidence that early diagnosis and surgical bile drainage is associated with longer survival of the native liver.
Most of the diagnostic tests that are used to determine the etiology of cholestasis in infants are operator dependent and variable in utility, and most are not commonly performed outside of referral centers. Although specific circumstances may support the performance of diagnostic testing at a referring hospital, most practitioners will need to use the diagnostic expertise of a referral center. Diagnostic workup by referring hospitals may be most useful to quickly exclude some of the many causes of cholestasis.
For all diagnostic tests reviewed, the sensitivity and specificity varied widely. Percutaneous liver biopsy had the greatest diagnostic accuracy in published studies. However, because of the dynamic and progressive nature of extrahepatic biliary atresia, even this test can be misleading. Scintigraphy appears to be primarily useful in excluding extrahepatic obstruction, consistent with the diagnosis of extrahepatic biliary atresia. Sonographic evaluation is currently useful for excluding anatomic abnormalities but may have a greater value in the future if descriptions of new findings (such as the “triangular cord” sign) are corroborated. ERCP may have a role in centers with pediatric gastroenterologists experienced in its use. Too little experience with MRCP has been reported to analyze its utility. Duodenal aspirate or string test may be useful in remote sites or if other testing is not readily available.
In summary, the diagnosis of neonatal cholestasis is an urgent matter. This guideline and algorithm have been developed to assist in this process. No single pathway appears to be clearly superior for the diagnosis of conditions leading to cholestasis. A guide is provided here for clinicians who are challenged with the prospect of detecting and evaluating the rare infant with cholestasis. Vigilance is crucial in detecting these patients, selecting appropriate and timely diagnostic testing based on the resources available in their own institutions, and referring the infant to a pediatric gastroenterologist who can provide the essential diagnostic and treatment modalities for optimal outcome. The scarcity and relatively low quality of research found in this area indicate that further research is needed.
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