Case history

James, aged 14 years and 3 months, has been referred by his general practitioner with concerns about his growth.

James is the eldest child of professional parents and has become concerned that his friends and his 12-year-old sister are now taller than he is.

Health and medical history

Question 1.
What other information would you want to ascertain?

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Physical examination

Question 2.
What are the differential diagnoses?

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Question 3.
Which baseline investigations would you now undertake?

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Next steps

A short course of testosterone (intramuscular 50–125 mg/month for 3–6 months) can then be given to “kick-start” puberty and stimulate growth. 

GH stimulation test?
With height between the 25th and 50th centiles, GH deficiency would be very unlikely. There is no real evidence of growth failure so this would not be organized at this point. James’s height is still within target range and height velocity (HV) is appropriate for a prepubertal boy, and GH tests are not pleasant. If a GH stimulation test is performed, it should be preceded by sex steroid priming, ie, diethylstilbestrol 1 mg twice daily for the 2 days prior to the test.

LHRH test?
A LHRH (luteinising hormone releasing hormone) test can be done but is unlikely to be able to help differentiate between constitutional delay of growth and puberty and hypogonadotrophic hypogonadism at this stage. Organising the test may also delay the initiation of testosterone therapy, so discussion with James and parents about the value of this versus a short course of testosterone is important.

HCG stimulation test?
A human chorionic gonadotrophin (HCG) stimulation test not a suitable option at this stage as there is no evidence of, or risk factors for, gonadal failure.

Management plan

  • Discuss normal growth and puberty in boys and reassure James that this is most likely to be simply delayed and there are options available to help him catch up with his peers.
  • Discuss that slowing of growth is often seen peri-pubertally – but equally James is just growing at a rate that is normal during childhood and this looks as though it is slowing because the centile charts show the pubertal spurt.
  • Explain that the puberty growth spurt occurs rather late in boys, ie, well after puberty has started. Discuss the differences in boys and girls. James’s sister will have had her growth spurt, as girls have theirs at the beginning of puberty. Reassure James that his growth spurt will come.
  • As seen in the diagram, the growth spurt usually occurs once testicular volumes reach 10–12 mL. The height gain expected during puberty is around 20–25 cm which will bring James comfortably into his target range.
  • Highlight the importance of adequate calorie intake to fuel both the exercise and pubertal growth.

During the discussion it is clear that James is finding his situation very difficult. He is being teased at school and he is very concerned that he will lose his place in the football team as he is unable to match the physical strength and speed of his peers. He and his parents are clear he wants treatment.

Results of baseline tests:

Test Result Comment
Full blood count Normal
Renal profile Normal
Liver function test Normal Low albumin can indicate inflammatory bowel disease
FT4 11.7 pmol/L Normal
TSH 2.1 mU/L Normal
CRP
ESR
<1
2 mm/hr
Normal – elevated levels seen in chronic inflammatory conditions
IGF-1 22.9 nmol/L Normal level for puberty stage
Bone profile Normal
Coeliac screen Negative
LH 2.2 iu/L Normal prepubertal level
FSH 2.7 iu/L Normal prepubertal level
Testosterone 0.8 nmol/L Normal prepubertal level 9 am sample
Prolactin 142 mU/L Normal
Bone age 12 yr 1 month 2-year delay
ACTH & Cortisol Not done Not clinically indicated
IGFBP3 Not done Not clinically indicated
Genetic studies Not sent Not indicated at present. Consider if discordant pubertal progression or persistent hypogonadotrophic hypogonadism

What next?

Short course of testosterone – consider both routes and allergies.
Some available preparations contain arachis oil, and should be used with caution in those with peanut allergy (and soy allergy, due to cross reactivity). The arachis oil does not contain peanut protein and therefore most individuals with peanut allergy will tolerate the preparation, unless their sensitivity is very high.

Advantages and disadvantages of testosterone preparations  

Route Advantages Disadvantages
Intramuscular
  • Cheap
  • Known efficacy
  • Lots of experience of use
  • Long-acting
  • Easy dose titration
  • Licensed in UK
  • Can monitor consistency of use
  • Fluctuating drug levels resulting in fluctuating symptoms (mood and libido, which may be an issue in boys with learning difficulties)
  • Local problems with injections (pain, inflammation, sterile abscess)
  • Need for appointment with healthcare service for administration
  • Potential for priapism if excess dose administered
Transdermal
  • Pharmacokinetics most closely replicate         natural diurnal variation
  • Convenient
  • Evidence of efficacy lacking
  • Doses extrapolated from adults
  • More expensive
  • Possible transfer to other persons
  • Skin irritation
  • Not licensed in UK
Oral
  • Convenient
  • Easy dose titration
  • Licensed in UK
  • Lack of evidence regarding efficacy
  • Variable absorption and metabolism
  • Gastrointestinal side effects
  • Frequent dosing (3 times daily)

Reference

James was keen to have a short course of testosterone.

In practice the majority of centres prescribe intramuscular preparations as it is easier to ensure correct dosage and concordance. This makes it clearer when evaluating response. James was prescribed testosterone 75 mg once a month for four doses.

An appointment was made for review in 6 months.

On examination 6 months later

Question 4.
Is this what you would expect? What is the definitive diagnosis?

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What will you do next?

LHRH test?
James may have hypogonadotrophic hypogonadism and an LHRH test will help confirm whether there is gonadotropin deficiency. In approximately 10% of boys, hypogonadotropic hypogonadism resolves following the introduction of sex steroids. So further investigation can be deferred and done alongside other investigations if there is no further pubertal progression following a second course of testosterone.

HCG test?
A HCG test is not indicated – the basal investigations do not suggest primary gonadal failure and if there is ongoing hypogonadotrophic hypogonadism then the results of a standard HCG test may not be reliable

Second course of testosterone?
A small proportion of boys require a second course of testosterone to stimulate the start of puberty. Another course of 3–6 months is usually given. If this is required, causes of systemic illness should be investigated again.

GH test?
There is still no clear evidence of true growth failure – but this may be considered if James or parents are concerned. An increase in HV following testosterone therapy strongly argues against a diagnosis of GH deficiency.

Management plan

On discussion James wanted to pursue treatment with testosterone rather than delay and have further investigations. He and parents were reassured that his growth spurt would occur once puberty commenced and did not want any GH tests.

James’ next review was in 6 months following another four injections of testosterone 75 mg.

Age: 15 years 3 months
Height: 167.2 cm
Weight: 52 kg
HV: 7.83 cm/yr
BMI: 18.6 kg/m2
Tanner stage: Pubic Hair 3; Genitalia 3; testicular volume 8 mL on left, 10 mL on right

The increase in HV and further development of his genitalia and pubic hair is likely to be partly due to the testosterone injections.

However, the increase in testicular volume indicates that James is now in puberty.

James is still frustrated that he is not yet catching up with his friends.

It is important to manage the expectations of James and his parents and not give unrealistic predictions of his adult height. It is likely that he has inherited more of his mother’s growth genes than his father’s.

Boys with constitutional delay of growth and puberty do not reach their mid-parental height centile.

Remind the parents that boys have their peak height velocity (growth spurt) later than girls. This would be expected once testicular volumes are around 10–12 mL – so would not be expected yet but will happen.

It may also be reassuring for James to understand that having a late puberty will have no impact on his gender identity or sexual orientation.

James was offered a further appointment for review in 9 months’ time, but if he and his parents are happy with his growth and have no further concerns they can cancel this.


Presented by Pauline Musson
Clinical Nurse Specialist
Southampton Children’s Hospital

 

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