SAT-296 Congenital Adrenal Hyperplasia Presenting as Central Precocious Puberty

Background: Sometimes peripheral precocious puberty (PPP) is the underlying cause of central precocious puberty (CPP) and is called as secondary CPP. In most of the secondary CPP, the role of the PPP is evident at diagnosis of CPP. Here we report a case of secondary CPP who was initially misdiagnosed as idiopathic CPP. Case presentation A-6.25-years-old boy, born of a third degree consanguineous consummation, presented with appearance of pubic hair and enlargement of phallus since the age of 4 years. He has history of mild global developmental delay, predominantly affecting language milestones. There was no family history of early puberty, sibling deaths or ambiguous genitalia. His height was 113 cm (-0.54 SDS ) and mid-parental height was 176.5 (+0.31 SD), Sexual maturity rating was P3, G3 (stretched phallic length: 6 cm) and bilateral testes measuring 5 cc each. He had multiple large café-au-lait spots over the lower extremities with irregular borders. Bone age was 9.5 years. Serum testosterone was elevated (190.1 ng/dl) with LH of 0.31 mIU/ml and FSH of 1.25 mIU/ml. Thyroid function was normal (TSH: 1.11 µIU/ml, FT4: 1.56 ng/dl). Leuprolide stimulation was done which suggested central precocious puberty (peak LH: 10.61mIU/ml, peak FSH: 3.75 mIU/ml). MRI of the pituitary hypothalamic area was normal. He was diagnosed to have idiopathic CPP and was initiated on leuprodile depot preparation 3.75 mg intramuscularly once a month. After 6 months, he had grown 5 cm (and basal serum testosterone was still elevated (185.3 ng/dl), LH: <0.01 mIU/ml). Adequate LH suppression was also confirmed with suppressed LH (peak LH: 0.95 mIU/ml) after leuprolide depot stimulation. Hence, he was suspected to have secondary CPP and was evaluated for the cause. Serum 8:00 am cortisol was 7.48 µg/dl and β-hCG was undetectable. Basal 17OHP (16.79 ng/ml) and ACTH stimulated 17OHP (54 ng/ml) were elevated. Hence, a diagnosis of simple virilising CAH with secondary CPP was done. Patient was started on oral hydrocortisone (10 mg/m2/day) and shifted to leuprodile depot preparation 11.25 mg Q12 weekly. After 3 months basal serum testosterone was 45 ng/ml and LH was < 0.01 mIU/ml. Conclusion: In a patient with hormonal profile suggestive of CPP, a disproportionately smaller testes for a given serum testosterone should suggest a secondary cause for CPP. In patients treated with GnRH agonist for CPP, persistent growth acceleration and/or persistently elevated sex steroid but well-suppressed LH should also suggest a secondary cause for CPP.