The exocrine pancreas is functionally immature at birth.<sup>21 Lebenthal E., Lee P.C. Development of the functional response in human exocrine pancreas Pediatrics 1980 ;  66 : 556-560

Cliquez ici pour aller à la section Références, 35 Zoppi G., Andreotti G., Pajno-Ferrara F. , et al. Exocrine pancreas function in premature and full term neonates Pediatr Res 1972 ;  6 : 880-886

Cliquez ici pour aller à la section Références</sup> Protease function is probably adequate, but lipase activity approximates 5% to 10% of adult values in the newborn and remains low in infancy. Pancreatic amylase secretion is essentially absent at birth and remains low through the first years of life. Except possibly in times of extreme metabolic or nutritional stress, pancreatic immaturity does not appear to be of clinical importance in infancy. Nevertheless, healthy infants (<6 months) have physiologic steatorrhea.

The exocrine pancreas has a large functional reserve capacity. This finding was first demonstrated in adults in the classic studies of DiMagno et al,<sup>4 DiMagno E.P., Go V.L.W., Summerskill W.H.J. Relations between pancreatic enzyme outputs and malabsorption in severe pancreatic insufficiency N Engl J Med 1973 ;  288 : 813-815  [cross-ref]

Cliquez ici pour aller à la section Références</sup> who showed that pancreatic maldigestion did not occur until pancreatic enzyme secretion decreased to less than 10% of control values. Using more sensitive enzyme assays, it was shown that approximately 98% to 99% of enzyme secretory capacity must be lost before clinical evidence of malabsorption is evident.<sup>8 Gaskin K.J., Durie P., Lee L. , et al. Colipase and lipase secretion in childhood onset pancreatic insufficiency: Delineation of patients with steatorrhea secondary to relative colipase deficiency Gastroenterology 1984 ;  86 : 1-7

Cliquez ici pour aller à la section Références</sup> The term pancreatic insufficiency (PI) is used to define patients who have incurred loss of exocrine function to the point of being unable to digest and assimilate nutrients normally. By inference, symptoms of PI develop when more than 98% of pancreatic reserve is lost. The term pancreatic sufficiency (PS) describes patients with evidence of pancreatic dysfunction but in whom pancreatic reserve remains above the threshold for development of maldigestion.

Functional disturbances of the exocrine pancreas are less frequent in childhood than in adult life, but there is a wide spectrum of causes that are likely to be genetic or congenital in origin. Causes of pancreatic dysfunction in childhood can be divided into two general categories: (1) hereditary conditions that directly affect the pancreas and (2) acquired disorders in which loss of pancreatic function is a secondary phenomenon (Table 1). Most inherited causes of pancreatic dysfunction are due to a generalized disorder. Cystic fibrosis (CF) is the commonest inherited cause of disturbed pancreatic function among white children. Rarely, disturbance of pancreatic function may arise as a result of disordered embryogenesis. On a worldwide basis, however, acquired pancreatic dysfunction resulting from severe malnutrition is probably more frequent. The precise frequency and severity of the pancreatic defect after malnutrition and its clinical importance, however, are poorly defined.