Perineal ultrasound offers useful information in girls with congenital adrenal hyperplasia.
A variable spectrum of urogenital malformations exists in girls with congenital adrenal hyperplasia (CAH). The vagina may enter the urethra at a variable level, and relations to the sphincter complex vary accordingly. Furthermore, an enlarged clitoris and variations in the bladder sphincter anatomy can be found. Endoscopy, genitography or magnetic resonance imaging (MRI) are commonly used for the assessment of these anomalies, and to provide information for counselling and treatment. When surgery is planned, introitoplasty cosmetical reduction of the clitoris and labioplasty are discussed with the families; introitoplasty is the most demanding aspect. In order to plan the most appropriate surgical approach, the entrance level of the vagina into the urethra and its relation to the bladder sphincter must be known. Thus, imaging has an important role in CAH. The imaging techniques mentioned above require sedation, anaesthesia or involve ionizing radiation of the gonads and, thus, are relatively invasive. It would therefore be highly desirable to have a minimally invasive and accurate technique that provides images of the individual anatomic situation. The present paper describes experience with perineal ultrasound in the initial imaging evaluation of girls with CAH. Ultrasound findings were compared to the results of endoscopy that was performed before surgery. From 2006 to 2012, 11 girls had perineal ultrasound and endoscopy. Measurements of clinical relevance for introitoplasty were: the length of the urogenital sinus, the distance to the vaginal opening into the urogenital sinus, and the length of the bladder neck. This retrospective analysis showed that the entrance point of the vagina into the urogenital sinus could be identified in 10 of 11 girls. In some cases, the correlation of endoscopic and ultrasound data showed a correlation between endoscopic and sonographic findings. The length of the bladder neck and the length of the urogenital sinus could be measured by ultrasound in 10 of 11 girls, and were subsequently confirmed by endoscopy. This showed, for the first time, that perineal ultrasound could provide the information required for surgical correction of the urogenital sinus anomaly in CAH. Advantages of these techniques are the minimal invasiveness and wide availability. Because long-term problems are not uncommon, perineal ultrasound may also be of value during follow-up. Widespread use of this technique has the potential to reduce costs and morbidity associated with endoscopy and genitography.