Core Clinical Cases in Paediatrics PDF

1Growth problems Questions Clinical cases Key concepts Answers  2 Growth problems ? Questions for each of the clinical cases Q1: What is the likely differential diagnosis? Q2: What issues in the given history support the diagnosis? Q3: What additional features in the...

1Growth problems Questions Clinical cases Key concepts Answers  2 Growth problems ? Questions for each of the clinical cases Q1: What is the likely differential diagnosis? Q2: What issues in the given history support the diagnosis? Q3: What additional features in the history would you seek to support a particular diagnosis? Q4: What clinical examination would you perform, and why? Q5: What investigations would be most helpful, and why? Q6: What treatment options are appropriate? Clinical cases CASE 1.1 – My 6-year-old son is the shortest in his class. A 6-year-old boy was seen in the paediatric outpatient department. His parents complained that he was the shortest boy in his class, and he could not reach the coat pegs in school. On examination, the child’s height was 106 cm (3rd centile). CASE 1.2 – My 5-year-old daughter is developing breasts. A 5-year-old girl was referred to outpatients because of early breast development. This had been present since birth, but is increasing. She was on no medication. On examination, her height was 117 cm (98th centile). Breast development was Tanner stage 2. CASE 1.3 – My 14-year-old daughter has not yet started her periods. A 14-year-old girl was referred for investigation of delayed puberty. She was born at full term, after a normal pregnancy. Her general development was normal, and she attended a mainstream school. On examination, she was prepubertal.  OSCE counselling cases 3 OSCE counselling cases OSCE COUNSELLING CASE 1.1 – Can you give my son something to make him taller? OSCE COUNSELLING CASE 1.2 – Why is my child overweight?  4 Growth problems Key concepts In order to work through the core clinical cases in this chapter, you will need to understand the following key concepts. Phases of childhood growth z Infancy phase: from birth to 2–3 years, the fastest period of growth. It is determined mainly by nutrition. z Childhood phase: from 2–3 years to the onset of puberty, and is determined mainly by hormones, including growth hormone, thyroxine and insulin. z Adolescent growth spurt: occurs from the onset of puberty to fusion of the epiphyses, and is determined by the synergistic action of growth hormone and sex hormones (androgens and oestrogens). Fusion of epiphyses A gradual process initiated by the secretion of oestrogen from the adrenals in boys and ovaries in girls. Epiphyseal fusion limits final adult height. Precocious puberty The development of secondary sexual characteristics before the ages of 8 years in females and 9 years in males. One example is thelarche, which is the isolated development of breast tissue without pubic or axillary hair development. Delayed puberty The absence of pubertal development by 14 years of age in females and 15 years in males. Tanner staging The classification of pubertal development according to the appearance of pubic hair in males and females, breast development in females, and external genital development in males. Stage 1 is prepubertal, stage 5 is adult. Orchidometer A series of beads of increasing size from 2 mL volume to 24 mL volume used to assess testicular size. Testicular volume increases in proportion to testosterone secretion. Volumes of 2–3 mL equates to prepubertal testicular size; 12 mL volume is attained at the time of maximum height velocity. From 12 mL upwards is normal for male adults. Measurement of height and height velocity z To determine the true height velocity, children should have their height measured on two occasions at least 6 months apart. This reduces measurement inaccuracies due to observer error. The accuracy of a single height measurement is ± 0.5 cm. Inter-observer error is similar. To minimize these errors, the height should be measured by the same person, on the same equipment, with a minimum interval of 6 months.  Key concepts 5 z The height attained over a 6-month period can be doubled to express a height velocity in cm per year. Centile charts exist for height velocity. A child’s height velocity needs to remain above the 25th centile in order to maintain the centile on a linear growth chart. z Height velocity below the 25th centile for at least 18 months equates to a child drifting down the centiles on a linear growth chart, and is one definition of growth failure. Estimation of final adult height from parents’ height (mid-parental height) To estimate a boy’s final height, add 12.5 cm to mother’s height and take the mean of the mother’s adjusted height and the father’s height (mid-parental height). For a girl’s final height, subtract 12.5 cm from the father’s height and take the mean of the adjusted father’s height and the mother’s height. The 95 per cent confidence limits for the child’s predicted adult height are the mid-parental height ± 8 cm. Turner syndrome z A common cause of short stature in girls, with a prevalence of about 1 in 5000. It is caused by the absence of one of the sex chromosomes, giving a karyotype of 45XO. z Features include short stature, web neck, wide carrying angle at the elbow, convex nails, shield-shaped chest, low posterior hairline, ovarian dysgenesis (defective development), and normal intelligence (but sometimes difficulty in socialization). z Girls with Turner syndrome are relatively growth hormone-resistant, but they do benefit from growth hormone treatment, which can increase their final height by about 5 cm. z These girls also need hormone replacement in the form of oestrogens to induce puberty. z Many children and parents benefit by getting in touch with a family support group such as the Child Growth Foundation.  6 Growth problems Answers CASE 1.1 – My 6-year-old son is the shortest in his class. Q1: What is the likely differential diagnosis? A1 z Familial short stature. z Constitutional delay of growth. z Psychosocial causes of short stature. z Isolated growth hormone deficiency. Q2: What issues in the given history support the diagnosis? A2 The boy is on the third centile for height, which means that 3 per cent of the population of 6-year-olds are shorter than him. He is within the normal range of height for a UK population. Consequently, he is likely to be a short, normal boy. A Q3: What additional features in the history would you seek to support a particular diagnosis? A3 z Ask how long the parents have been worried, i.e. has he always been short or small; is there any history of chronic illness? (e.g. coeliac disease (q.v.), heart or kidney disease) z Was he a normal birth and delivery? (ask about birthweight). Was he born premature or growth restricted? (constitutional short stature) z What ethnic group is the family from? (ethnic differences in height) How tall are his parents? (familial short stature) z What is the social background and family relationships? (emotional neglect or other forms of child abuse are causes of psychosocial short stature) z Is he falling behind his peers? (height falling off centiles as in growth hormone deficiency) Q4: What clinical examination would you perform, and why? A4 z Measure his parents’ height and plot them on the growth chart. z Estimate mid-parental height.  Answers 7 Q5: What investigations would be most helpful, and why? A5 z Take serial height measurements at least 6 months apart. z Calculate height velocity. If height velocity is below 25th centile over 6 months, other investigations would include: z Measurement of insulin-like growth factor-1 (IGF1) as a surrogate marker of growth hormone. z X-ray of the left wrist to ascertain bone age or skeletal maturity. This is delayed in growth hormone deficiency. Other causes of bone age delay include hypothyroidism and coeliac disease. z Growth failure is an indication for formal pituitary testing with a dynamic growth hormone stimulation test such as the insulin stress test in which a small dose of insulin is given to induce hypoglycaemia. This is a potent stimulus for growth hormone secretion, and serial measurements assess the peak secretion. Q6: What treatment options are appropriate? A6 z The most likely diagnosis is familial short stature. No treatment is necessary, but reassurance that the child is normal. z Constitutional short stature is usually not amenable to treatment, although some children with Russell Silver syndrome (a disorder of short stature, hemihypertrophy, incurved little fingers, and triangular shaped face) do benefit from growth hormone therapy. z Psychosocial short stature will respond to elimination of the causes of emotional neglect or other forms of child abuse. This may require removal of the child from the abusing environment. CASE 1.2 – My 5-year-old daughter is developing breasts. Q1: What is the likely differential diagnosis? A1 z Isolated thelarche. z Thelarche variant. z Precocious puberty. Q2: What issues in the given history support the diagnosis? A2 The child is not on any medication, and some breast development has been present since birth.  8 Growth problems A Q3: What additional features in the history would you seek to support a particular diagnosis? A3 z Ask whether parents have noticed any pubic hair or unusual mood swings (precocious puberty). In addition, has the child been growing rapidly over the past 1–2 years, as in an adolescent growth spurt? z Has anyone else in the family had early breast development? Did this progress to precocious puberty? Q4: What clinical examination would you perform, and why? A4 z Plot the growth on a height and weight chart, together with previous measurements to gauge her height velocity. A rapid height velocity would suggest an adolescent growth spurt, and precocious puberty. Check mid-parental height. z Examine for pubic and axillary hair – again, signs of precocious puberty – and perform an abdominal examination for masses. z Consider neurological examination. Intra-cranial tumours are a rare cause of precocious puberty, more common in boys, and usually resulting in disconsonant puberty (pubic hair without testicular enlargement). Q5: What investigations would be most helpful, and why? A5 z If there are no other signs of puberty, then isolated premature thelarche is the most likely diagnosis. This is a benign condition, and may not require follow-up. Parents can be instructed to contact the doctor again if further signs of puberty develop. z If the child’s height is above the expected centile for the parents’ height, then serial measurements of growth are required to detect a premature growth spurt. In addition, a bone age X-ray will give an indication of possible advanced bone age. If the bone age is advanced in the absence of other signs of puberty, the child fits into the category of thelarche variant. These children are at risk of developing precocious puberty, and require follow-up. z The presence of other signs of puberty such as pubic hair, warrants further investigations. These include a pelvic ultrasound for ovarian follicles and uterine size, and a luteinizing hormone-releasing hormone (LHRH) test. An injection of LHRH is given, and luteinizing hormone (LH) and follicle-stimulating hormone (FSH) measured at time points after. The magnitude of the rise in LH and FSH indicates whether the child is prepubertal, in early puberty, or established puberty. True precocious puberty is usually of central origin at the level of the hypothalamus, and the cause is unknown. Q6: What treatment options are appropriate? A6 z The most likely diagnosis is isolated premature thelarche. In this situation, the parents can be reassured and the child does not need to be followed-up.  Answers 9 z If thelarche variant is present, the child needs follow-up as she is at risk of precocious puberty. z If precocious puberty is present, it is important to delay further progression to avoid compromising final height, and to prevent the onset of menarche in primary school. The available treatment is depot injection of a gonadotrophin- releasing hormone agonist such as goserelin. This acts by down-regulating the release of LH and FSH from the anterior pituitary, and may regress pubertal signs. CASE 1.3 – My 14-year-old daughter has not yet started her periods. Q1: What is the likely differential diagnosis? A1 z Familial delayed puberty. z Turner syndrome. z Systemic illness. z Anorexia nervosa. Q2: What issues in the given history support the diagnosis? A2 This girl is presumably of normal development and intelligence as she attends a mainstream school. Age at menarche has a large genetic component, and tends to run in families. However, Turner syndrome must be excluded. A Q3: What additional features in the history would you seek to support a particular diagnosis? A3 z Ask about mum’s age at menarche, and the ages of menarche of any sisters. z Is the girl short compared to her peers? (Turner syndrome) z Does she have any chronic illness such as cystic fibrosis (q.v.) that would explain her delayed puberty? z Are there any factors in the social history that would lead you to suspect anorexia (pressure of examinations, unusual fixation with food, unwillingness to develop adult interests and behaviour). Q4: What clinical examination would you perform, and why? A4 z Plot height and weight on a growth chart. Check the parents’ height. z Look for short stature in relation to parents’ heights (Turner) and underweight for height (anorexia).  10 Growth problems z Assess her pubertal stage. Is she prepubertal? (the commonest situation in Turner) z Does she have hyperteleorism, web neck, wide carrying angle of the arms, shield chest, hypoplastic nails, underdeveloped nipples, or other signs of Turner syndrome? Q5: What investigations would be most helpful, and why? A5 z Chromosome karyotype. The normal female complement should be 46XX. Turner girls are usually mosaic (i.e. they have a mixture of cells, some normal 46XX karyotype, some 45XO karyotype). z LHRH test (q.v.). This will establish if the hypothalamo-pituitary-gonadal axis is intact, and exclude primary gonadal failure. z X-ray the left wrist for bone age. Look for delayed bone age in most causes of delayed puberty. Q6: What treatment options are appropriate? A6 z If the diagnosis is familial delayed puberty, the girl can be reassured that she will achieve a final adult height within the range predicted by her parents’ heights. z Girls with Turner syndrome need genetic counselling. z If a systemic illness is diagnosed, then specific treatment will be required. z Anorexia nervosa is a life-threatening condition that needs specialist child psychiatry input.  OSCE counselling cases 11 OSCE counselling cases OSCE COUNSELLING CASE 1.1 – Can you give my son something to make him taller? This is a common question asked by parents of short and not-so-short children. z Children who are ‘short normal’ – i.e. due to familial short stature or constitutional short stature – do not need treatment other than reassurance that they are healthy. Trials of growth hormone in short normal children have not shown any appreciable increase in final adult height. Growth hormone is indicated for growth hormone deficiency, Turner syndrome, Prader–Willi syndrome, Russell–Silver syndrome and in chronic renal failure. z If growth hormone is indicated, the child and parents should be counselled about its use. Growth hormone is administered by daily subcutaneous injection until the child’s height velocity falls below 2 cm per year (usually until mid-late teens). z The family may wish to contact a parent support group such as the Child Growth Foundation. z Regular monitoring of the child’s growth is required to assess compliance and the effects of treatment. z Many children with isolated growth hormone deficiency recover normal growth hormone secretion by puberty. They all need retesting at the end of the growth period. z The benefit of exogenous growth hormone in growth hormone-deficient adults is controversial; there is some evidence that it improves general well-being and cardiac muscle contractility. However, this must be balanced against the cost of this very expensive drug. OSCE COUNSELLING CASE 1.2 – Why is my child overweight? Children are often brought to general paediatric clinics because of obesity. z Find out in the history if there is any indication of pathology such as tiredness and lethargy in hypothyroidism, growth failure in Cushing’s syndrome (very rare in children). Enquire about diet and exercise, and look at the phenotype of the parents (are the parents overweight as well?). z Measure blood pressure, assess fat distribution (uniform in exogenous obesity), abdominal striae, acanthosis nigricans (sign of insulin resistance). z The most likely diagnosis is exogenous obesity. This frequently induces more rapid growth and some advance in bone age. The family needs to be reassured that there is no underlying pathology. z Explain that weight is determined by the balance of calorie intake and energy expenditure. z Give dietary advice to reduce the fat content in the diet, reduce salt and increase fibre. z Give exercise advice and suggest 30 minutes of exercise that makes the child breathless, every day. z Set realistic targets for weight, and give positive encouragement. This page intentionally left blank