Endocrine Abstracts

Introduction: Avascular necrosis of the femoral head (AVN) is most commonly a consequence of glucocorticoid excess and is believed to be due to osteocyte apoptosis. It can also be due to vascular occlusion or trauma. We describe a patient with congenital adrenal hyperplasia secondary to 17-hydroxylase deficiency who presented with osteoporotic vertebral fractures and atraumatic avascular necrosis of the femoral head. She was also found to have mild cardiomyopathy.

Case report: We report a case of a 38-year-old female who was referred to endocrinology outpatients with primary amenorrhea. She had a BMI of 30 and mild hypertension. Initial investigations showed low baseline cortisol of 19 nmol/l and 30-minute cortisol of 29 nmol/l on SST with a high ACTH of 192ng/l and corresponding low salivary cortisol/cortisone levels, confirming primary adrenal insufficiency. Further studies revealed low androgens, LH 30.4IU/l, FSH 56.9IU/l, oestradiol <91.8 pmol/l and high progesterone of 23.3 nmol/l. MRI pelvis showed a small uterus, no ovary identified, and early avascular necrosis of the right femoral head supported by severe osteoporosis on DXA scan. She was started on hydrocortisone, an intravenous bisphosphonate and continued on HRT. Following treatment, her BP improved. Her ECHO showed mild dilated cardiomyopathy. A urine steroids test confirmed the diagnosis of 17-hydroxylase deficiency with a high level of corticosterone metabolites and a high pregnanediol to pregnanetriol ratio. In addition, androstenedione, DHEA and cortisol metabolites were low. Genetic studies confirmed the diagnosis of autosomal recessive 17-hydroxylase deficiency – (pathogenic CYP17A1 variant c.753+1G>A).

Discussion: - AVN has never been reported previously as a complication of untreated 17-hydroxylase deficiency in the literature. The pathophysiology is unclear. Moreover, mild cardiomyopathy is an unusual finding. - If untreated, 17-hydroxylase deficiency may lead to significant multi-organ long-term consequences such as osteoporosis complicated by vertebral fractures. We recommend early screening for osteoporosis in such patients.