Endocrine Abstracts

Introduction: The male child with congenital adrenal hyperplasia (CAH) due to 21 hydroxylase deficiency classically presents with salt-wasting and the female with genital ambiguity. 17-OHP measurement is a key investigation but the assay takes time to perform and is not usually available at weekends. We have examined the role of renal/adrenal ultrasonography in the above clinical scenarios.

Method: An abdominal ultrasound focussing on adrenal anatomy was performed following the presentation of a baby with suspected CAH (March–June 2013). The images were viewed jointly by radiologist and paediatric endocrinologist. The radiological diagnosis (CAH or not) was compared with the final diagnosis made on the basis of a range of indices including 17-OHP values.

Results: There were four babies with suspected CAH. Cases 1–3 were male infants, 2–5 weeks of age, with a salt wasting picture (sodium 119, 120 and 128 mmol/l, potassium 6.7, 7.2 and 6.5 mmol/l). Case 4 had genital ambiguity noted at birth. A diagnosis of CAH was made in infants 1, 2, and 4 on the day of presentation on the basis of a normal renal tract but characteristically enlarged, irregular, echogenic adrenal glands. Grossly elevated 17-OHP concentrations were identified 2–5 days after the initial presentation (2681, 2882, and 2159 nmol/l). Imaging was normal in infant 3 and 17-OHP concentrations were age appropriate. He was diagnosed with pseudohypoaldosteronism on the basis of his biochemistry and urine steroid profile.

Conclusion: Adrenal ultrasonography is a key diagnostic tool when investigating suspected CAH with high sensitivity/specificity. It can be undertaken in the first hours following presentation, the images are easy to interpret and the test means that CAH can be diagnosed promptly out of hours. In two of the above cases the diagnosis was made at the weekend. UK guidance should highlight the role of adrenal ultrasonography in greater detail.