title: Serum and bile bilirubin pigments in the differential diagnosis of Crigler-Najjar disease.
abstract: OBJECTIVE
  To differentiate between Crigler-Najjar (CN) disease types 1 and 2.
  
  
  METHODS
  The patterns of serum bilirubins, bile pigment composition, and phenobarbital response were studied.
  
  
  METHODS
  Three infants, affected by high serum unconjugated bilirubin concentrations, previously classified as type 1 CN.
  
  
  METHODS
  Serum and bile bilirubin pigment composition, both before and after phenobarbital (PB) treatment, were determined by alkaline methanolysis and high-pressure liquid chromatography. PB was given for at least 3 weeks by oral administration (5 mg/kg bw per day).
  
  
  RESULTS
  No diconjugated bilirubin was found either before or after PB treatment in the serum of the three studied infants. In two patients traces of monoconjugated bilirubin were detected before PB therapy, and the ratio of conjugated/total bilirubin (percent) was increased by the PB response. In the third patient, traces of monoconjugated bilirubin appeared only after PB administration. However, the serum unconjugated bilirubin concentration decreased significantly only in the second patient, following the second cycle of PB treatment, leading to the diagnosis of type 2 CN. The analysis of the methyl ester derivatives of bile pigments was also performed on bile samples obtained in two patients by Entero-Test (R) both before and after PB treatment. An absolute increment in monoesterified bilirubin concentration was found after PB administration, although the percent concentration increased in one case and decreased in the other. No diesterified bilirubin was detected in the bile samples.
  
  
  CONCLUSIONS
  The present results show that in types 1 and 2 CN disease it is possible to detect traces of monoconjugated but not diconjugated bilirubin both in serum and in bile. Whereas PB treatment is effective in slightly increasing the serum monoconjugated bilirubin concentration even in type 1 CN disease, the diagnosis of type 1 or 2 is based on finding a substantial decrease of serum unconjugated bilirubin following PB administration.
authors.affiliation: Department of Pediatrics, University of Padova, Italy.
authors.forename: F F
authors.initials: FF
authors.lastname: Rubaltelli
authors.forename: A
authors.initials: A
authors.lastname: Novello
authors.forename: L
authors.initials: L
authors.lastname: Zancan
authors.forename: M T
authors.initials: MT
authors.lastname: Vilei
authors.forename: M
authors.initials: M
authors.lastname: Muraca
mesh_terms: D000284:Administration, Oral; D001646:Bile / Q000737:chemistry*; D001654:Bile Pigments / Q000032:analysis*; D001663:Bilirubin / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D003414:Crigler-Najjar Syndrome / Q000145:classification / Q000175:diagnosis* / Q000188:drug therapy / Q000378:metabolism; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010634:Phenobarbital / Q000627:therapeutic use
chemical_list: D001654:Bile Pigments; D001663:Bilirubin; D010634:Phenobarbital