A 13-year-old boy has not started puberty. Testicular volume is 2 mL bilaterally, no pubic hair, height 148 cm (below 3rd centile), height velocity 4 cm/year. His father started puberty at 16 years. LH and FSH are both low. Bone age is 11 years. Olfactory testing is normal. What is the MOST likely diagnosis and appropriate initial management?
- A Constitutional delay of growth and puberty (CDGP); reassure and offer low-dose testosterone to expedite puberty ✓
- B Hypogonadotropic hypogonadism (Kallmann syndrome); treat with GnRH pump
- C Primary hypogonadism (Klinefelter syndrome); hormone replacement
- D Growth hormone deficiency; recombinant GH therapy
Explanation
Constitutional delay of growth and puberty (CDGP) is the most common cause of delayed puberty in boys, characterized by positive family history, low bone age (confirming delayed but not deficient pubertal axis), normal LH/FSH (which are low because puberty has not started, not because of gonadotropin deficiency), and normal smell (rules out Kallmann syndrome). Management involves reassurance and, if significant psychosocial impact, a short course of low-dose testosterone enanthate (50 mg IM monthly for 3–6 months) to initiate puberty. Kallmann syndrome has anosmia; Klinefelter has small, firm testes and elevated FSH/LH.
Reference: Ghai Essential Pediatrics, 10th ed.
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Written and medically reviewed by the StethoPrep medical team.