Puberty

Adolescence is a time when young people become particularly sensitive to their appearance and differences from their peers (see Chapter 2). They also are anxious about puberty onset and progress, although they may not overtly express these anxieties. For example, males more commonly present for assessment of delayed puberty, although there is little indication that the incidence varies much between the sexes (4). Common working definitions

Box 2 Assessment of Pubertal Delay

Trigger questions:

■ How do you compare yourself to peers in your class? Are you small? Do they appear more or less developed than you?

■ How do you like your body? What about it would you like to be different?

■ Have your periods started?

Bear-in-mind factors influencing pubertal development:

■ Ethnicity—black females enter puberty around one year earlier than white females and proceed through menarche around 6 months earlier

■ Family history—there is some concordance with parental age of puberty onset

■ Nutrition—chronic malnutrition can delay, while overnutrition can advance, puberty onset

■ Bone age—a young person's bone age, rather than chronological age, best concurs with pubertal development of delayed puberty requiring assessment are: no breast development by 13 years or no menses by 15 years in females and prepubertal testes volume (<4mL) at 14 years in males. While the majority will have constitutional delay, assessment is required to identify those requiring intervention, whether for psychological reasons or for pathologic delay. It is also important to try and ascertain which is more distressing to the young person: lack of pubertal changes or the associated short stature.

Just as height is assessed at each visit, an assessment of pubertal stage should also be made (Box 2). This allows for early identification of abnormalities, as well as allowing reassurance to be given. Historical information in addition to the chronic rheumatic disorder and its management should include: parental ages of puberty onset; symptoms suggestive of other hormonal disorders; past illnesses, their treatment and any surgery. Physical assessment should include: current and previous height and weight; pubertal staging according to Tanner and Marshall (Figs. 6 and 7) including determination of any significant discrepancy between gonadal (breast or testes) and adrenal (pubic hair) development; body proportions; and dys-morphic features. Assessment following referral to a pediatric endocrinol-ogist will also involve neurological examination, visual fields, fundoscopy, and sense of smell.

Young people often find pubertal assessment embarrassing. Pictorial and written aids for self-assessment have been developed for use by adolescents. Studies assessing the reliability and validity of such assessments in different adolescent populations have shown inconsistent results (27-32). Concordance with physician examination ranged from fair to good with both over- and underestimation, varied by aspect of development (genital vs. pubic hair), ethnicity, and sex, with female self-assessments generally more reliable. If used in a clinical setting, they should not be relied upon for treatment decisions, but rather as a screening tool.

One of the most useful initial investigations is an X-ray of the left hand and wrist to assess bone age. However, this is unlikely to be useful in a proportion of young people with chronic rheumatic conditions with delayed growth and development. Those with JIA systemic onset or polyarthritis and associated growth abnormalities are more likely to have growth-plate damage in the hand and wrist secondary to their arthritis, making a bone age assessment difficult.

Delayed puberty in those with chronic rheumatic conditions is most commonly reversible, whether from a constitutional delay (family history of delayed puberty) or active inflammation and its treatment, particularly systemic steroids. If a bone age can be obtained, a delayed bone age is usually found, indicating potential for further height growth.

Table 3 outlines the differential diagnosis of delayed puberty (4,33-36). While not exhaustive it provides an approach to clinical evaluation and investigation. Two broad categories can be established by baseline

Table 3 Differential Diagnosis of Delayed Puberty

Condition

Hypogonadotrophic hypogonadism: Low

LH and FSH Reversible deficiency

Constitutional delay of growth and pubertal development

Chronic illness and/or malnutrition

Psychogenic disorders Excessive exercise Endocrine disorders Cushing syndrome Hyperprolactinemia Hypothyroidism Permanent deficiency

Hypothalamic-pituitary defects Acquired

Chemotherapy/irradiation/ surgery

Tumors Congenital

Panhypopituitarism Isolated gonadotrophin deficiency Kallman syndrome

Congenital midline defects

Hypergonadotrophic hypogonadism: High

LH and FSH Chromosomal disorders

Klinefelter syndrome (47 XXY) Turner syndrome (45 X0) and variants Other variants of ovarian and testicular gonadal dysgenesis

Features/investigations

Bone age delayed by more than 2 SD Delayed puberty and growth spurt (otherwise normal history and examination) Height velocity normal for bone age (growth parallel to 3rd percentile for late pubertal development) Family history delayed puberty Normal final height History/examination/screening and confirmatory test History/examination History/examination History/examination/respective hormone profiles

History/examination Neurological examination/MRI head

LHRH test with other pituitary hormones

Normal childhood growth, LHRH test with other pituitary hormones Normal childhood growth /sense of smell, LHRH test History/examination/MRI head

Dysmorphic features/body proportions/ karyotype

(Continued)

Table 3 Differential Diagnosis of Delayed Puberty (Continued)

Condition

Features/investigations

Testicular abnormalities

Anorchism/cryptorchism/ testicular torsion

History/examination

Chemotherapy/irradiation/surgery to gonads

History

Viral infections, e.g., mumps orchitis

History

Biochemical evaluation

Some types of congenital adrenal hyperplasia e.g., 17a-hydroxylase deficiency

Autoimmune disorders, e.g.,

Serum autoantibodies oophoritis

Abbreviations: LHRH, luteinizing hormone-releasing hormone; SD, standard deviation.

LH and FSH levels. In addition, there is a group of miscellaneous disorders, for example, Prader-Willi syndrome, Noonan syndrome, and testicular feminization.

It can often be difficult distinguishing between constitutional delay and other causes of hypogonadotrophic hypogonadism, and referral to a pediatric endocrinologist is recommended. Those with constitutional delay tend to also have delayed adrenarche (low DHEA-sulphate levels), while those with permanent causes of hypogonadotrophic hypogonadism tend to have normal onset of adrenarche, and therefore appropriately increasing DHEA-sulphate levels (37). There is however considerable overlap between the two groups. Recently, further attempts to help this distinction have included measurement of 8am testosterone levels: for those with levels greater than 0.7nmol/L, 77% will have an increase in testicular volume to 4 ml or more within 12 months, and 100% within 15 months; while only 12% and 25% will do so within 12 and 15 months respectively with levels below 0.7 nmol/L (37). More definitive measures are still awaited while we continue to mostly rely on the passage of time to give the ultimate answer.

In addition, females may enter puberty normally and progress without establishing menstruation, while others may progress through menarche but then develop secondary amenorrhea. The differential diagnoses for primary amenorrhea in a pubertal female and secondary amenorrhea (36) are presented in Table 4.

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