NUTRITION IN CHILDREN WITH EXTRA HEPATIC BILIARY ATRESIA
Dr D A Kelly, Consultant Paediatric Hepatologist
The Liver Unit, Birmingham Children's Hospital NHS Trust and Reader in Paediatric Hepatology, University of Birmingham

Biliary atresia is the commonest cause of cholestatic liver disease in childhood and the main indication for liver transplantation. Approximately 60% of infants with chronic cholestasis become malnourished; the aetiology of which is multifactorial. The pathophysiology includes increased energy expenditure, inadequate calorie intake secondary to anorexia, fat malabsorption of fat soluble vitamins, long chain triglycerides (LCT) and essential fatty acids (EFA) and protein malnutrition secondary to abnormal hepatic metabolism.

Recent research has demonstrated that only 50% of LCT and EFA are absorbed in children with extra hepatic biliary atresia compared to 95% of medium chain fat (MCT). Disappointingly, supplementation with MCT (in concentrations greater than 50% of total fat) does not improve linear growth indicating the necessity for long chain fat and essential fatty acids. Recent data indicates that decosahexanxoic acid (DHA) can be supplemented orally and prevents deficiency in cholestatic children.

It has been more difficult to evaluate the aetiology of protein malnutrition. Recent studies of protein turnover using 13C leucine have demonstrated that, in contrast to normal children, protein degradation continues despite feeding in children with liver disease but can be reversed by using a 50% branch chain amino acid supplemented feed. In this group of children with cholestatic liver disease, the rate of protein retention correlated with subsequent catch up growth and may be a useful indicator for future therapy.

Strategies to prevent the development of malnutrition particularly pre transplant, are based on intensive nutritional support providing an energy intake of between 140-200% estimated average requirement (EAR). In infants this is best provided by using a modular feed of carbohydrate 15-20 g/kg/day (glucose polymer); up to 8 g/kg/day of fat (MCT to LCT in ratio 50/50), whole protein 3-4 g/kg/day in association with generous fat soluble vitamin supplementation.

For those children with inadequate weight gain or anorexia, nasogastric tube feeding is usually required. Although the development of ascites and fluid retention means that feed volume must be restricted, this can be balanced by concentrating feeds even further to 1.6-2 kilocals/ml. It is unusual to require parenteral nutrition except for children with very advanced liver disease or recurrent variceal bleeds who do not tolerate oral feeding. The importance of the liver in the aetiology of malnutrition is amply demonstrated by the satisfactory nutritional rehabilitation achieved following successful liver transplantation.

References

Beath S, Johnson T, Willis K, Hooley I, Brown G, Booth I, Kelly D.
Superior absorption of medium chain triglycerides compared with conventional deitary long chain fats in children with chronic liver disease. Proc Nut Soc 1993; 52: 252.
Spray CH et al. Docohexanoic acid (DHA) in visual function in infants with malabsorption secondary to liver disease. Proceeding of the Nutritional Society 54; 108a.
Protheroe S et al. 1996. Failure to suppress protein breakdown contributes to malnutrition in infants with liver disease. Hepatology 24: (4) part 2, 141a
Protheroe S and Kelly DA. Cholestasis in end stage liver disease. IN; Nutritonal support in Paediatric Gastrointestinal Disease. ED: 0 Goulet, Publisher Balliere's. 1998 823-843.
Kelly DA. Nutritional factors effecting growth before and after liver transplantation.
Paediatric Transplantation 1997; 1: 80-84.

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