A 14-year-old boy with an unremarkable medical history presents to his pediatrician with concerns about his short height and lack of pubertal development as compared to his peers. His father relates to the pediatrician that he was a “late bloomer.” His height has been progressing along the 5th percentile and his weight has been at the 10th percentile. His physical exam reveals Tanner stage 1 and prepubertal sized testes, but is otherwise normal. The pediatrician makes the diagnosis of constitutional delay of growth and puberty, reviews the expected growth and development with the family, and recommends watchful waiting (Figure 199-1). The boy begins spontaneous sexual development at 15 years of age and his growth velocity increases shortly thereafter.
Delayed puberty is defined as a lack of initiation of secondary sexual development in boys 14 years or older and in girls 13 years or older. The majority of boys with delayed puberty have constitutional delay of growth and puberty (CDGP), defined on the basis of a normal physical examination and a growth chart showing short stature but normal growth velocity. Pathologic delayed puberty may be due to primary endocrine disorders such as gonadal failure, isolated gonadotrophic deficiency, panhypopituitarism, or chronic underlying diseases.
CDGP is the single most common cause of delayed puberty in both sexes, but it can be diagnosed only after any underlying pathologic causes have been ruled out.1
CDGP occurs more commonly in boys than in girls.
Hypergonadotrophic hypogonadism, also known as primary gonadal failure, is more common in girls.
Competitive swimmers, gymnasts, and ballet dancers are at high risk for functional hypogonadotrophic hypogonadism.
CDGP represents the single most common cause of delayed puberty in both sexes. The cause is unknown but a genetic predisposition with an autosomal dominant effect as well as environmental modifiers is likely.1–3
Causes of hypergonadotrophic hypogonadism include Turner syndrome, gonadal dysgenesis, chemotherapy, or radiation therapy to testes or ovaries, and autoimmune ovarian function. The diagnosis is based on demonstrating very high levels of Follicle stimulating hormone (FSH).
Functional hypogonadotrophic hypogonadism (FHH) occurs in 20 percent of boys and girls referred for delayed puberty. Underlying conditions include eating disorders (anorexia or bulimia) and other chronic systemic illnesses such as inflammatory bowel disease, celiac disease, cystic fibrosis, and hypothyroidism. Excessive exercise is a relatively common cause of delayed menarche in girls. Although body fat is decreased in those affected, BMI is often in the normal range because of an increase in muscle mass.
Permanent hypogonadotrophic hypogonadism (PHH) is diagnosed in 10 percent of boys and 20 percent of girls with delayed puberty. Two types occur: (1) Isolated gonadotrophin deficiency (IGD) or (2) Multiple pituitary hormone deficiencies (MPHD).2,3
Most boys who have not had spontaneous pubertal development by 18 years or girls by 16 years have PHH, if they do not have risk factors for FHH.
About half of boys with delayed puberty due to PPH also have defective smell (anosmia or hyposmia), which is called Kallman syndrome. The most common form is due to a mutation in a gene on the X chromosome.
Acquired MPHD is caused by tumors of the hypothalamic-pituitary axis or a head and neck tumor requiring radiation therapy with the pituitary gland in field of radiation. Rarely an infiltrative process such as Langerhans cell histiocytosis can be a cause of acquired MPHD.
Genetic factors—Fifty to seventy-five percent of children with CDGP has at least one parent with pubertal delay and inheritance is often autosomal dominant.1
Decreased body fat in girls is a common risk factor associated with pubertal delay.
Excessive exercise.
Chronic illness and obesity are implicated in some cases of pubertal delay.
