Neonatal hypopituitarism presenting with poor feeding, hypoglycemia and prolonged unconjugated hyperbilirubinemia

Reduced Hepatocellular Expression of Canalicular Transport Proteins in Infants with Neonatal Cholestasis and Congenital Hypopituitarism

OBJECTIVE

To assess whether prolonged neonatal cholestasis, described in congenital hypopituitarism and septo-optic dysplasia (SOD), is associated with altered expression of selected canalicular ectoenzymes and canalicular transport proteins.

STUDY DESIGN

Children with congenital hypopituitarism (n = 21), SOD (n = 18), and cholestasis seen in our center over 26 years were reviewed. Histopathologic findings in archival liver biopsy specimens were assessed (n = 10) and in those with low/normal levels of serum γ-glutamyltransferase (GGT) activity despite conjugated hyperbilirubinemia, expression of canalicular ectoenzymes and canalicular transport proteins was evaluated immunohistochemically.

RESULTS

Patients presented at a median age of 8 weeks (range 3-20 weeks) with median total bilirubin 116 µmol/L (45-287 µmol/L), GGT 95 IU/L (25-707 UI/L), and serum cortisol 51 nmol/L (17-240 nmol/L). All but 3 had low free thyroxin (median 9.6 pmol/L [6.8-26.9]) with increased thyroid-stimulating hormone levels (median 5.95 mU/L [<0.1-9.24]). Liver histologic features included moderate-to-severe intralobular cholestasis with nonspecific hepatitis, giant-cell transformation of hepatocytes, and fibrosis. In all, immunohistochemical staining for canalicular ectoenzymes and canalicular transport proteins revealed a degree of reduced expression, associated with normal serum GGT values in 6 of the 10 patients, and another 6 nonbiopsied infants with cholestasis also had low/normal serum GGT activity. Sequencing of ABCB11 and ATP8B1 performed in 6 of the biopsied patients did not identify pathogenic mutations. Following replacement therapy, biochemical evidence of hepatobiliary injury resolved in all children within a median period of 6 months.

CONCLUSION

Hepatobiliary involvement in congenital hypopituitarism associated with SOD has a good prognosis, but its etiology remains uncertain. Immunohistochemical expression of canalicular transport proteins was reduced in available liver samples.

Underlying etiologies of prolonged icterus in neonates

The purpose of this study was to determine underlying causes of prolonged neonatal icterus. Icterus or jaundice is an important common problem in neonatology. When this condition persists beyond 14 days, it is called prolonged or protracted neonatal icterus. Determining underlying causes of this problem is a pivotal step for management, because a delay in treatment may lead to serious complications or even death. In a prospective study, newborns with diagnosis of prolonged icterus were evaluated during a six-month period in Tabriz Children Teaching Hospital. Data regarding the past medical history, physical examination and appropriate laboratory and paraclinical investigations were gathered and accordingly, the underlying cause of jaundice was documented. One hundred newborns, 67 males and 33 females with a mean age of 21.5 +/- 4.5 days were enrolled. Breastfeeding, urinary tract infection, glucose 6-phosphate dehydrogenase deficiency and hypothyroidism were found as the main underlying causes in 75, 7, 7 and 4% of the cases. The exact etiology was unknown in 4% of newborns. ABO incompatibility, sepsis and Down syndrome were underlying etiologies in remaining three patients. Present study showed that the underlying causes of prolonged neonatal jaundice could be determined in majority of cases and breastfeeding is the most common one in this regard.