Constitutional delay and familial short stature — formative SAQs

SAQ 1 (10)

A seven-year-old boy is referred because he is the shortest in his class. Both parents are short (father 162 cm, mother 150 cm). His birth weight was 3.1 kg at term. His height tracks just below the third centile and has done so since toddlerhood, with a normal growth velocity. His bone age equals his chronological age. [1] [2]

a) Define short stature and calculate this child's approximate mid-parental (target) height range. State the diagnosis you favour and the single investigation that confirms it. (3 marks) [1]

b) Explain why the bone age is the discriminator between familial short stature and constitutional delay of growth and puberty, and state the expected bone age in each. (3 marks) [2]

c) Name the focused blood panel you would send to exclude the pathological mimics, and give one reason for each test. (3 marks) [1]

d) Explain why growth hormone is not indicated for this child, and state the principle that governs its use in the normal variants. (1 mark) [2]

SAQ 2 (10)

A fourteen-year-old boy is distressed that he has no signs of puberty while his peers are well into theirs. His father began shaving at seventeen and his mother's menarche was at fifteen. His height has drifted down through the centiles in childhood. His bone age reads eleven years, and his height is appropriate for that bone age. His testes are 3 mL bilaterally. [3] [4]

a) Give the diagnosis, the two clinical features that support it, and the expected natural history for his final adult height. (3 marks) [3] [4]

b) Explain why this presentation can be indistinguishable from permanent hypogonadotrophic hypogonadism at first assessment, and name two features that would favour the latter (including Kallmann syndrome). (3 marks) [3]

c) Outline the management, including the role of reassurance and surveillance and the circumstances in which a short course of testosterone would be offered. State a representative dose and duration. (3 marks) [3] [4]

d) State the single growth-chart finding that would exclude a normal-variant diagnosis and demand investigation, and name two pathological causes it would suggest. (1 mark) [1]