BALTIMORE — Consider a wide range of causes when evaluating a child for a growth disorder, Leslie Plotnick, M.D., said at a meeting on pediatric endocrinology sponsored by Johns Hopkins University.
Although growth hormone treatment is approved by the Food and Drug Administration for some conditions, not all children with growth problems are growth hormone deficient, and a thorough evaluation is important, including a complete history and physical examination.
“A child with normal growth will track along a percentile line,” said Dr. Plotnick, a pediatric endocrinologist at Johns Hopkins University. Growth velocity normally decreases prior to puberty, until the adolescent growth spurt begins.
Consider evaluating children for growth problems when the growth rate is less than 5 cm/yr from age 3 years to 12 years, Dr. Plotnick advised. In addition, consider the possibility of a growth disorder when a child's height is below the 5th percentile or when height drops across percentiles over time. Another sign is when a child's height is more than two standard deviations below the average height of the biologic parents.
Causes of short stature or poor linear growth include major organ system diseases that are cardiac, pulmonary, renal, gastrointestinal, nutritional, hematologic, or CNS-related. In addition, chromosomal disorders such as Turner's syndrome; intrauterine growth retardation; endocrine disorders; or, simply, familial short stature or constitutional growth delay can cause a child to grow at a slower than average rate.
Although evidence of any association remains uncertain, oral or inhaled glucocorticoids might contribute to delayed growth. Long-term data on the impact of other medications—including stimulants, antidepressants, antiseizure medications, and antipsychotics—on growth delay remain inconclusive as well.
Carefully monitor height and weight patterns in children who take these medications, Dr. Plotnick said. Changes from established pretreatment growth patterns suggest a medication effect and may require further evaluation.
Endocrine-related causes of short stature include hypothyroidism, cortisol excess, pseudohypoparathyroidism, poorly controlled diabetes mellitus, and growth hormone deficiency. Features associated with these conditions include goiter, dry skin, midline defects, micropenis in boys, and an especially round, cherubic face.
The screening work-up for short stature is extensive and includes a complete metabolic profile, complete blood count, thyroid function test, and celiac screen.
A definitive diagnosis of growth hormone deficiency requires at least two tests that indicate a growth hormone level of less than 10 ng/mL, including arginine, L-dopa, clonidine, glucagon, and insulin-induced hypoglycemia. If a child appears to have growth hormone deficiency, conduct a brain MRI and test other pituitary axis hormones, she added.
Growth hormone deficiency can be congenital or genetic, or it can be acquired as a result of brain tumors, infiltrative diseases, head trauma, infection, central nervous system surgery, or central nervous system irradiation to treat a tumor.
For more specific information about growth patterns in children and to download the current growth charts from the Centers for Disease Control and Prevention, visit www.cdc.gov/growthcharts