Clinical Handbook In Adolescent Medicine, A: A Guide For Health Professionals Who Work With Adolescents And Young Adults

A Guide for Health Professionals Who Work with Adolescents and Young Adults

Kate Steinbeck, Michael Kohn

• Publisher: WSPC
• Year: 2013
• ISBN:
  9789814518819
• Topic: Medicine
• Subtopic: Pediatric Medicine

This clinical handbook is a valuable resource for any health professional who works with adolescents and young adults, whether in paediatric or adult acute care facilities or in the community. As a handbook it provides ready access to practical, clinically relevant and youth specific information.

This clinical handbook fills a clear gap, as most adolescent texts are primarily directed at paediatricians. This handbook extends its scope beyond paediatrics for three important reasons. First, many adolescents are managed by adult trained clinicians who have not had much exposure to or training in adolescent health. Secondly, the important health conditions of adolescents are often the important health conditions in young adults. Thirdly, with increased survival rates in chronic illness over the last two to three decades, it is becoming essential that clinicians in adult health care are able to assess and manage conditions that have their origins in childhood.

Each chapter is written by an expert in their field with a highly practical approach. The information is relevant and straightforward, with the aim of enhancing clinical skills.

Contents:

• Normal Physical Development and Growth at Puberty (Geoffrey Ambler)
• The Normal Development of the Adolescent Brain (Donna M Palmer and Leanne M Williams)
• Normal Psychosocial Development in Adolescence (David Bennett and Richard G MacKenzie)
• Body Image Issues in Adolescents (Jennifer O'Dea)
• Communicating with Adolescents (Richard G MacKenzie)
• Consent and Confidentiality (Michelle Yeo)
• Communicating with Parents and Carers (Anne Honey and Gwynneth Llewellyn)
• Communicating Electronically with Adolescents (Fiona Robards and Andrew Campbell)
• Education Issues (Margaret Allan)
• Adolescents and Young Adults in Adult Hospitals (Gail Anderson, Tegan Sturrock and Patricia Kasengele)
• Self-Management in Chronic Illness; Promoting Therapy Adherence (Michele Casey and Kate Steinbeck)
• Complex Medicopsychosocial Conditions: Chronic and Functional Disorders (Susan J Towns and Helen E Bibby)
• Transition from Paediatric to Adult Care in Chronic Illness (Sandra Whitehouse, Lynne Brodie and Susan J Towns)
• Resilience (Emily Klineberg)
• Alcohol and Other Drugs (Bronwyn Milne, Yvonne Bonomo and Gilbert Whitton)
• Unintentional Injuries Among Adolescents and Young Adults (Richard E Bélanger and Joan-Carles Suris)
• Rural and Remote Australian Adolescent Health Issues (Catherine Hawke)
• Important Medical and Mental Health Issues for Incarcerated and Homeless Youth (Stephen Stathis, Lee Hudson and Andrew Kennedy)
• The Dying Adolescent (Michael Stevens, Julie Dunsmore and John Collins)
• Disorders of Puberty (Ann Maguire and Kate Steinbeck)
• The Deaf Adolescent (Eric Weiselberg)
• The Adolescent and Young Adult with Intellectual Disability and Complex Health Needs (Helen Somerville and Cameron Ly)
• Key Issues in Adolescent Obesity (Shirley Alexander, Alison G Hoppin and Louise A Baur)
• Adolescents with Eating Disorders (Jorge L Pinzon, Gail Anderson and Simon Clarke)
• Adolescent Sexuality, Sexual and Reproductive Health (Melissa Kang, Rachel Skinner and Deborah Bateson)
• Physical Activity and Sports Medicine (Carolyn Broderick and Damien McKay)
• Depression and Anxiety (Sloane Madden)
• Assessment and Treatment of Psychotic Disorders in Adolescence (Jean Starling and Anthony Harris)
• Suicide and Self-Harm (Philip Hazell)
• Mental Health in Young People with Intellectual Disability and Autism (David Dossetor and Rameswaran Vannitamby)
• Sleep and Sleep Disorders in Adolescents (Karen Waters)
• Attention Deficit Hyperactivity Disorder (Michael R Kohn and Deborah Erickson)
• Immunisation and Infectious Diseases (Melina Georgousakis, Alexa Deirig and Robert Booy)
• Respiratory Disorders in Adolescence (Donald Payne and Siobhain Mulrennan)
• Common Adolescent Endocrine Disorders (Shubha Srinivasan)
• Diabetes During Adolescence (Kristine Heels, Nuala Harkin and Kim C Donaghue)
• Adolescent Bone Health (Craig Munns)
• Common Neurological Disorders (Richard Webster)
• Common Gastrointestinal Disorders of Adolescence (Annabel Magoffin)
• Common Dermatological Problems in Adolescents (Anuja Elizabeth George)
• Common Haematological Conditions in Adolescence (Julie Curtin)
• Allergic and Immunological Disorders in Adolescence (Alyson Kakakios, Dianne Campbell, Paul Turner and John Tan)
• Cancer in Adolescents and Young Adults (Bhavna Padhye and Melissa Gabriel)
• Late Effects of Childhood Cancer Therapy (Helena Gleeson)
• Common Cardiology Problems in Adolescence (Mugur Nicloae and Dorothy Radford)
• Adolescent Renal Medicine (Siah Kim and Deirdre Hahn)
• Common Rheumatological Conditions in Adolescence (Davinder Singh-Grewal)
• Genetics and Adolescents (David Sillence)
• Urological Problems in Adolescence (Grahame H H Smith)
• Common Gynaecological Problems in Adolescence (Kim Matthews and Peter Benny)
• The Andrology of Adolescence (David J Handelsman)
• Cardiovascular Risk Factors and Atherosclerosis (Marc S Jacobson and Michael R Kohn)

Readership: Clinicians, nurses, doctors and all other professionals in healthcare.

Chapter 1

Normal Physical Development and Growth at Puberty

Geoffrey Ambler

1. Introduction

Puberty is the biological process in which children undergo physical and sexual maturation with the ultimate attainment of adult body characteristics and reproductive capability. It includes primary sexual development (gonadal and genital growth and maturation), secondary sexual development (such as sexual hair development, female breast development, and male voice changes), accelerated height and weight growth and changes in the body composition. Crucially, these biological changes occur in the context of a complex process of psychosocial and cognitive maturation. As well as the hypothalamic–pituitary–gonadal axis, puberty involves a coordinated response from other hormonal systems including the growth hormone and adrenal axes.

The following terms are often encountered in the description of puberty and related processes:

• Thelarche — the onset of breast development in girls.
• Pubarche — the onset of sexual hair development in boys or girls.
• Menarche — the onset of the first menstrual period in girls.
• Gonadarche — the onset of mature gonadal function (sperm production in boys or ovulation in girls).
• Adrenarche — the onset of adrenal androgen production in boys or girls.

2. The Physiology of Puberty

2.1. Activation of the Hypothalamic–Pituitary–Gonadal Axis

The onset of puberty is activated through the central nervous system and requires pulsatile secretion of the hypothalamic hormone gonadotropin releasing hormone. GnRH secretion is controlled by the GnRH ‘pulse generator’ which has been localised to the arcuate nucleus. Pubertal activation of the GnRH pulse generator is through the effects of the neuropeptide kisspeptin and its G-protein coupled receptor. Other gene products and receptors involved include GnRH, GnRH receptor, FGFR1, leptin, and the leptin receptor.

With the onset of puberty, pulsatile GnRH secretion increases in frequency and amplitude, at first during the night. With progression through puberty, there is a relatively greater rise in luteinising hormone pulses and levels than follicle stimulating hormone levels in both sexes as a result of GnRH stimulation.

Sex steroid secretion rises progressively in puberty in association with the rise in gonadotropin secretion. In girls, LH secretion induces the production of androstenedione and testosterone in the ovarian theca cells and FSH induces the aromatase enzyme in follicular cells to produce oestradiol. Oestradiol induces breast development, changes in body shape and composition, a growth spurt, and then growth plate fusion through its effects on growth plates (epiphyses). In early puberty, oestradiol secretion is greatest at night, but subsequently increases during the daytime hours with menarche usually occurring after a year-long rise in daily oestradiol secretion. From late puberty, a series of negative and positive feedback loops that alter gonadotropin secretion are responsible for the mature reproductive cycle. This includes oocyte development, ovulation, and menses, which continues cyclically unless pregnancy occurs (Chapter 50).

In boys, pulsatile gonadotropin secretion induces testicular enlargement and function. LH stimulates the Leydig cells to produce testosterone and maintain spermatogenesis, while FSH stimulates the Sertoli cells and initiates and regulates spermatogenesis, although there is integration of these two systems at several levels. Testosterone (itself and through local tissue conversion to dihydrotestosterone) is the predominant hormone responsible for male virilisation, body composition changes and growth spurt. Oestradiol production (through aromatisation of testosterone and androstenedione) is still responsible for growth plate closure. The hormone Inhibin B progressively rises in boys also, indicating integrity of seminiferous tubule function.

2.2. Adrenarche

The word adrenarche describes the increase in the secretion of the relatively weak adrenal androgens (predominantly DHEA, DHEAS and androstenedione) that commonly precede the true onset of puberty. Adrenarche is frequently the cause of the first signs of secondary sex characteristics (in particular pubic hair, axillary hair, oiliness of skin, mild acne and apocrine body odour). Adrenal androgens continue to rise through late puberty. Premature adrenarche is a normal variant condition (Chapter 20). Adrenarche (premature or normal) merges into the processes of true central puberty as the gonads become the predominant source of androgens. The control of the onset of adrenal androgen production remains poorly understood although it is believed to be independent of and not required for gonadarche.

2.3. The Growth Hormone Axis

In addition to activation of the gonadal and adrenal axes, puberty involves a coordinated increase in the activity of the growth hormone axis. There is a 2–4 fold increase in GH secretion during puberty and this parallels the growth spurt and hence occurs earlier in girls than boys. The increase in GH secretion is mediated by sex steroids. Increased secretion of GH stimulates increased production of insulin-like growth factor-1, mainly from the liver. Serum IGF-1 levels peak markedly with puberty and parallel sexual development and growth velocity. Levels are also significantly influenced by nutrition, general health, and liver function (lower in under-nutrition and ill-health). IGF-1 production is also directly stimulated by sex steroids in some tissues, especially cartilage. Growth hormone as well has direct effects on some tissues that are not mediated via IGF-1. Thus, the growth axis, in coordination with sex steroids, acts through endocrine, autocrine, and paracrine mechanisms.

Leptin, a hormone secreted mainly by adipose tissue, also increases during puberty and is known to have a role in regulation of weight gain, initiation of puberty, sexual development and changes in body composition. Leptin levels are strongly correlated with body mass index; its role in the initiation of puberty is thought to be permissive rather than primary.

3. Timing of Puberty and Secular Trends

It has been estimated that 50%–80% of the timing of puberty is determined by genetic factors, although the specific genetic factors responsible are not well characterised. In a number of countries the age of menarche declined from approximately 15.5 years in the mid-19th century and plateaued at approximately 12.7 years in the mid-20th century, although there are suggestions that it has risen again slightly in recent years. Suggested recent trends in earlier onset of puberty and menarche are likely to be related to overweight, but in females only. It should be noted that all such data analyses are limited by methodological issues and that no adequate data exist to assess secular trends for boys. There is also evidence for chronic family stress being associated with earlier menarche. Several studies have shown that girls who are adopted internationally into Western countries have significantly early puberty and an increased incidence of precocious puberty, compared to those immigrating with their families. In boys, excess weight gain in childhood may have the opposite effect with a relatively later onset of puberty. Endocrine-disrupting chemicals have also been proposed as being associated with earlier puberty (for example phthalates, phytoestrogens and polychlorinated biphenyls) although evidence is limited. Ethnic differences are well recognised in the timing of puberty; for example African American girls have earlier pubertal onset than white American girls.

4. Physical Changes of Puberty

Although wide variations occur in the timing of onset and tempo of puberty, the sequence of pubertal events is usually fairly orderly and predictable in both males and females. The stages of progression of secondary sexual characteristics in males and females were first comprehensively described by Tanner. Tanner staging descriptions and charts exist for pubic hair in males and females, breast staging in females and genital staging in males (Figs. 1 and 2). For the purposes of describing the timing and sequence of physical changes in puberty in the next sections, composite data are described from Tanner and other studies that reflect those widely used in clinical practice.

In addition to Tanner staging, there are other useful measures of pubertal progress. Measurement of testicular size in males is particularly useful to assess the onset and progression of puberty. This is best performed using an orchidometer. Stretched penile length can also be measured, if there is a concern, and compared to available standards, although this is not

Fig. 1: Genital and pubic hair staging in males (Tanner staging). Normal data on pubertal timing in boys are relatively few, however the mean age of achieving a testicular volume of 4 ml is reported to be 11.5–12 years (normal range 9.5–13.5 years). While the tempo of puberty can vary considerably, the average time for the completion of genital development is three years (range 2–4.7 years), although growth of the testes to adult volumes occurs over 5–7 years. The average adult testis is an ellipsoid with a volume of 18 ml (range 12–30 ml) and mean adult penile length is approximately 13 cm (range 10.5–15.3 cm).

Fig. 2: Genital and pubic hair staging in females (Tanner staging).

routine. In girls, ovarian ultrasound is a relatively simple and accurate measure of ovarian size when needed to evaluate gonadal development. Axillary hair is staged as (1) no hair, preadolescent; (2) scanty growth of slightly pigmented hair; or (3) hair, adult, in quantity and quality.

4.1. Physical Changes in Boys (see Fig. 1 and Table 1)

The earliest sign of puberty in boys is generally defined as testicular enlargement to ≥3 ml volume, although achieving 4 ml or longitudinal axis measurement of 2.5 cm is used by others. Testicular enlargement is an indicator of pulsatile gonadotropin secretion. Most of the increase in volume (approximately 70%) relates to develo...

Table of contents

• Cover
• A Clinical Handbook in Adolescent Medicine
• Title Page
• Copyrights
• Contents
• Foreword
• Acknowledgements
• Contributors
• Chapter 1: Normal Physical Development and Growth at Puberty
• Chapter 2: The Normal Development of the Adolescent Brain
• Chapter 3: Normal Psychosocial Development in Adolescence
• Chapter 4: Body Image Issues in Adolescents
• Chapter 5: Communicating with Adolescents
• Chapter 6: Consent and Confidentiality
• Chapter 7: Communicating with Parents and Carers
• Chapter 8: Communicating Electronically with Adolescents
• Chapter 9: Education Issues
• Chapter 10: Adolescents and Young Adults in Adult Hospitals
• Chapter 11: Self-Management in Chronic Illness; Promoting Therapy Adherence
• Chapter 12: Complex Medicopsychosocial Conditions: Chronic and Functional Disorders
• Chapter 13: Transition from Paediatric to Adult Care in Chronic Illness
• Chapter 14: Resilience
• Chapter 15: Alcohol and Other Drugs
• Chapter 16: Unintentional Injuries Among Adolescents and Young Adults
• Chapter 17: Rural and Remote Australian Adolescent Health Issues
• Chapter 18: Important Medical and Mental Health Issues for Incarcerated and Homeless Youth
• Chapter 19: The Dying Adolescent
• Chapter 20: Disorders of Puberty
• Chapter 21: The Deaf Adolescent
• Chapter 22: The Adolescent and Young Adult with Intellectual Disability and Complex Health Needs
• Chapter 23: Key Issues in Adolescent Obesity
• Chapter 24: Adolescents with Eating Disorders
• Chapter 25: Adolescent Sexuality, Sexual and Reproductive Health
• Chapter 26: Physical Activity and Sports Medicine
• Chapter 27: Depression and Anxiety
• Chapter 28: Assessment and Treatment of Psychotic Disorders in Adolescence
• Chapter 29: Suicide and Self-Harm
• Chapter 30: Mental Health in Young People with Intellectual Disability and Autism
• Chapter 31: Sleep and Sleep Disorders in Adolescents
• Chapter 32: Attention Deficit Hyperactivity Disorder
• Chapter 33: Immunisation and Infectious Diseases
• Chapter 34: Respiratory Disorders in Adolescence
• Chapter 35: Common Adolescent Endocrine Disorders
• Chapter 36: Diabetes During Adolescence
• Chapter 37: Adolescent Bone Health
• Chapter 38: Common Neurological Disorders
• Chapter 39: Common Gastrointestinal Disorders of Adolescence
• Chapter 40: Common Dermatological Problems in Adolescents
• Chapter 41: Common Haematological Conditions in Adolescence
• Chapter 42: Allergic and Immunological Disorders in Adolescence
• Chapter 43: Cancer in Adolescents and Young Adults
• Chapter 44: Late Effects of Childhood Cancer Therapy
• Chapter 45: Common Cardiology Problems in Adolescence
• Chapter 46: Adolescent Renal Medicine
• Chapter 47: Common Rheumatological Conditions in Adolescence
• Chapter 48: Genetics and Adolescents
• Chapter 49: Urological Problems in Adolescence
• Chapter 50: Common Gynaecological Problems in Adolescence
• Chapter 51: The Andrology of Adolescence
• Chapter 52: Cardiovascular Risk Factors and Atherosclerosis
• Abbrevations
• Index