Endocrine Abstracts

Background: 17 α-hydroxylase enzyme deficiency is a rare condition and is responsible for < 1% of cases of congenital adrenal hyperplasia (CAH). Females present with delayed puberty due to reduced production of sex steroids and males can present with female external genitalia or with various degrees of genital ambiguity.

Case presentation: A 4.5-year-old female – previously fit and well – presented to ED with fever and vomiting for 24 hours. On presentation, she had hypoglycaemia (1.6 mmol/L) with hypokalaemia (2.7 mmol/L) and normal blood pressure (BP). There was no hyperpigmentation with normal female external genitalia. Cortisol was 37 nmol/L at the time of hypoglycaemia and an early morning repeat was 12 nmol/L. The child was started on replacement doses of hydrocortisone. A synacthen test subsequently confirmed primary adrenal insufficiency with a peak cortisol of 25 nmol/L and elevated ACTH (101 ng/L, normal range 7.2 – 63.3). Anti-adrenal antibodies were negative. Other investigations were normal including Renin 7.5 mU/L (5.4–60), 17OHP <0.1 nmol/L, Androstenedione <0.4 nmol/L, DHEA-S <0.3 umol/L, and Testosterone <0.1 nmol/L. Abdominal ultrasound showed normal adrenal glands. Electrolytes have normalised now well. The urinary steroid profile (USP) confirmed a complete deficiency of 17 α-hydroxylase with elevated corticosterone metabolites and significantly low androstenedione, dehydroepiandrosterone (DHA), and cortisol metabolites. Genetic testing is awaited.

Conclusion: Patients with 17 α-hydroxylase enzyme deficiency commonly present with delayed puberty and / or hypertension and it is a rare form of CAH. We present a case of a child whose hypocortisolism was identified after a period of hypoglycaemia following an intercurrent illness. She was hypokalaemic (consistent with relative mineralocorticoid excess) though she maintained normal BP during the illness and when well. The key to diagnosis was the USP and we wait for genetic testing to identify the causative mutation. The mainstay of management is glucocorticoid replacement as soon as the diagnosis is made and sex hormone replacement at the expected time of puberty. Close monitoring of BP is essential as hypertension is a clinical feature due to elevated levels of 11-deoxycorticosterone (DOC), corticosterone, and 18-hydroxycorticosterone.