Chapter 522

Growth is a complex process that involves the interaction of multiple, diverse factors and represents the sum of these influences on cell replication and programmed cell death (apoptosis) and on cell differentiation. Growth is ultimately governed by the genome of a person and its interactions with external factors, such as nutrition and psychosocial well-being. Linear height growth may occur as a continuous process or with periodic bursts of growth and arrest.1-3During 1 year of growth monitoring, there may be marked seasonal variations of height and weight gain with several monthly bursts of weight and then height growth.4 Despite the complexity, healthy children usually grow linearly in a remarkably predictable manner. Change from a normal growth pattern often is the first manifestation of a disease, either an endocrine or a nonendocrine disorder that can involve almost any organ system. Frequent and accurate assessment of growth therefore is of primary importance in the care of children.

Growth rates differ during intrauterine life, early and middle childhood, and adolescence. During gestation, growth averages 1.2 to 1.5 cm per week but increases dramatically to a midgestational peak of 2.5 cm per week with a decline to 0.5 cm per week immediately before birth. Growth velocity during the first 2 years of life averages about 15 cm per year and slows to approximately 6 cm per year during middle childhood. The peak height velocity during the pubertal growth spurt is 7 to 11 cm/yr. The time of puberty onset and consequently the age at the pubertal growth spurt varies among healthy children. On average, girls begin and complete puberty earlier than do boys and thus stop growing earlier (at 14 to 15 years of age compared with 16 to 17 years for boys). This accounts for the approximately 13-cm difference in the adult heights of women and men. Despite variations in the age of onset of puberty, among most healthy children, final height is not influenced by the chronological time of onset of the pubertal growth spurt. Growth ceases after fusion of long bone and vertebral epiphyses. This occurs when chondrocyte proliferation in the growth plate slows and senescent changes occur in a process seemingly intrinsic to the biology of the growth plate.5,6

Because heredity is a significant determinant of growth, it is important to relate a patient’s height to that of siblings and parents. Tanner and associates developed a method by which stature of children can be assessed relative to midparental height. Mean parental height is calculated, and 6.5 cm is added for boys or subtracted for girls. The 2-SD (standard deviation) range for this calculated parental target height is approximately 10 cm. The possibility of an underlying pathological condition must be considered when a child’s growth pattern clearly deviates from that of the parents.7

Accurate height measurements are necessary for the evaluation of growth. Measurement of supine length should be used for children younger ...

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