Nutrition in children with cerebral palsy.

Abstract

Energy Expenditure and Body Composition in Children with Spastic Quadriplegic Cerebral Palsy. Azcue MP, Zello GA, Levy LD, Pencharz PB.J Pediatr 1996;129:870-6. Summary: In this study of 13 children with spastic quadriplegic cerebral palsy (SQCP), bioelectrical impedance analysis (BIA) was validated against 2H2O dilution to measure total body water (TBW) and against NaBr dilution to measure extracellular water (ECW). Resting energy expenditure (REE) was measured by indirect calorimetry. All 13 children with SQCP were fed by gastrostomy and were well nourished (mean weight was 105% of ideal body weight). Fat-free mass (FFM) (determined by skinfold thickness measurements and BIA), and TBW, intracellular water, and ECW (determined by BIA) were significantly lower in the children with SQCP than they were in control subjects. In both the SQCP and control groups, FFM, TBW, and ECW were similar when measured by anthropometry, dilution techniques, or BIA. The mean REE was significantly lower than that in control subjects or predicted values, and 9 of the 13 children also had reduced REE per unit body cell mass. The best predictor of REE was intracellular water derived from BIA, but the relationship was weaker in children with SQCP than it was in control subjects. The stable weight of the children indicated that energy expenditure and intake must have been similar and suggested a daily energy requirement of 1.1 times the measured REE. Estimation of REE based on World Health Organization equations and calculation of total energy needs, based on World Health Organization standards for healthy children (1.5 to 1.6 × REE), would lead to overestimation of energy requirements. The investigators recommend that in children with SQCP, individual energy expenditure should be measured to provide optimal nutritional care. Comment: Up to 85% of children with SQCP have severe feeding problems, and chronic malnutrition is a frequent result. As the results in this study indicate, nutritional assessment and management are major problems, because there are no standards for normal growth or energy requirements in these children. When height or length can be measured, weight-for-height or percentage ideal body weight can be calculated and is a measure of acute malnutrition. Linear growth measurement is difficult in up to two-thirds of children with SQCP, but such alternative measures of linear growth as the upper arm length and lower leg length can be measured reliably in 95% of cases(Dev Med Child Neurol 1989;31:206-14). Azcue et al. have demonstrated the value of BIA in the nutritional assessment of these children, but the equation that they have produced requires a height measurement. In a similar study, we developed equations, using upper arm length and lower leg length instead of height, and showed an excellent correlation with TBW measured by 2H2O dilution (Pediatr Rev Commun 1995;8:225-6). Although the similarity of the results for FFM, TBW, and ECW measured by anthropometry, dilution techniques, and BIA is reassuring, the fact that the FFM in control subjects was greater than the total body weight is worrying. Total body water was estimated by 2H2O dilution in the children with SQCP and by H218O dilution in the control subjects. The investigators point out that the theory and calculations are analogous, but it is well known that the 2H2O space is about 3% greater than the H218O space (Am J Clin Nutr 1980;33:2686-93). This alone would not explain the discrepancies, but it should be allowed for. Direct measurement of the hydration fraction of lean body mass is not possible in the clinical setting; but although this would influence the relationship between TBW and lean body mass, it would not affect the calculation of TBW itself. There must be some other problem with the method or the assumptions necessary in the calculation of these parameters. The lower REE is an important observation, because there is frequently great confusion about how much these children should be fed. In a recent study by Stallings et al. (Am J Clin Nutr 1996;64:627-34), the REE adjusted for FFM of control subjects was greater than that of children with SQCP who had low fat stores, but it was not significantly different from that of children with SQCP who had adequate fat stores. They suggested that the lower REE in the group with low fat stores may have been an adaptation to a chronically low food intake. The children studied by Azcue et al. were all well nourished, but presumably all had severe feeding problems, in that they were fed by gastrostomy. Whether adaptation could be an explanation for the low REE in these children would depend on whether they were malnourished before the gastrostomy and how long ago the procedure was performed. The investigators suggest that the reduced energy expenditure per unit of body cell mass points to the central nervous system as an important regulator of basal energy metabolism. Total energy expenditure (TEE) was measured by Stallings et al., using the doubly labelled water technique and was significantly reduced in both groups (adequate and low fat). The ratio of TEE to REE was significantly greater in control subjects (1.57), compared with that in children with SQCP who had low fat stores (1.29) or adequate fat stores (1.07). The latter is very similar to the ratio of 1.1 estimated by Azcue et al. and Bandini et al. (J Pediatr 1995;126:828-32). In results of these studies at least, the extra energy required for muscle spasticity and abnormal movements failed to outweight the reduced requirements because of immobility and perhaps because of chronic malnutrition. Mirajkar V. Suresh-Babu Adrian G. Thomas Department of Gastroenterology; Booth Hall Children's Hospital; Manchester, United Kingdom