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PITUITARY ANTERIOR LOBE DEFICIENCY IN CHILDHOOD AND ADOLESCENCE IN BOYS

PITUITARY ANTERIOR LOBE DEFICIENCY IN CHILDHOOD AND ADOLESCENCE IN BOYS

The most common deficient hormones in children and adolescents with anterior pituitary failure are the gonadotropins, luteinizing hormone (LH), and follicle-stimulating hormone (FSH). Gonadotropin deficiency may occur in isolation or in concert with other anterior pituitary hormone deficiencies. In the absence of gonadotropins in boys, puberty is delayed, and secondary sex characteristics do not develop (see Plate 4-7). The penis and prostate gland remain small, and the scrotum fails to develop rugae; the larynx fails to enlarge, and the voice maintains the high pitch of childhood. Some pubic hair appears, but it is usually sparse and fine. Axillary hair either does not appear or is sparse. Beard growth is absent.

Lack of androgens leads to prolonged persistence of open epiphysial plates and in the presence of intact growth hormone (GH) and insulin like growth factor 1 linear growth continues for longer than normal. The linear growth is particularly prominent in the extremities, and the arms and legs become disproportionately long. Eunuchoid proportions develop; lower body length (from the soles of the feet to the pubis) exceeds upper body length (from the pubis to the top of the cranium). In addition, the arm span exceeds the standing height (normally, these dimensions should be equal). Eventually, the epiphyses close in the third decade of life, even in untreated eunuchoid men. Administration of testosterone leads to prompt epiphysial closure. Excessive linear growth is not seen in adults with anterior pituitary deficiency after epiphysial closure.

PITUITARY ANTERIOR LOBE DEFICIENCY IN CHILDHOOD AND ADOLESCENCE IN BOYS


The presentation of secondary hypogonadism in adolescence may be affected by the presence or absence of other anterior pituitary hormone deficiencies. If GH is also deficient in childhood, short stature is evident. Short stature occurs when a child is 2 standard deviations or more below the mean height for children of that gender and chronologic age typically below the third percentile for height. The three phases of growth are infantile, childhood, and pubertal. Infantile growth is a rapid but decelerating growth pattern during the first 2 years of life with an average growth of 30 cm. A statistically significant and positive correlation exists between the height at age 2 years and final adult height. The childhood growth phase progresses at a relatively constant velocity of 5 to 7 cm per year. The pubertal growth phase refers to the growth spurt of 8 to 14 cm per year that occurs during puberty. The most common causes of short stature are genetic short stature and delayed growth. In addition to GH deficiency, the disorders that are most often associated with short stature are renal disease, cancer (and its treatment), glucocorticoid therapy, pulmonary diseases (e.g., cystic fibrosis), cardiac disorders (e.g., congenital heart disease), gastrointestinal disorders (e.g., celiac disease, inflammatory bowel disease), poorly controlled diabetes mellitus, vitamin D deficiency, hypothyroidism, and Cushing syndrome.

Additional anterior pituitary hormone deficiencies may contribute to the clinical presentation. For example, corticotropin deficiency may cause signs and symptoms of postural hypotension, tachycardia, fatigue, anorexia, weight loss, hyponatremia, and hypoglycemia. Thyrotropin deficiency may contribute signs and symptoms of fatigue, cold intolerance, constipation, facial puffiness with periorbital edema, dry skin, bradycardia, and delayed relaxation phase of the deep tendon reflexes.