Disorders of sex development — formative SAQs

SAQ 1 (10)

A two-week-old infant, recorded as male at birth with severe hypospadias and bilaterally impalpable gonads, presents to the emergency department with two days of vomiting, poor feeding, and lethargy. On examination the infant is dehydrated, with hyperpigmented scrotal skin, and the initial blood gas shows a metabolic acidosis with a sodium of 122, a potassium of 6.8, and a glucose of 1.6 mmol per litre. [11] [1]

a) What is the most likely diagnosis, and which single bedside examination finding, noted at birth, should have oriented the team to it? Explain why the appearance was misleading. (3 marks) [1]

b) Outline the immediate resuscitation, naming each component and the physiological rationale, and state the dose principle for the key medication. (3 marks) [11]

c) The karyotype returns as 46,XX. State how this is classified, and outline the lifelong replacement therapy and the monitoring the child will need. (2 marks) [11]

d) The parents ask whether the genitalia should be surgically 'corrected' before discharge. State the principle that governs cosmetic genital surgery in this condition, and the evidence and ethics behind it. (2 marks) [3] [12]

SAQ 2 (10)

A sixteen-year-old girl presents with primary amenorrhoea. She has normal breast development, scanty pubic and axillary hair, and a blind-ending vagina with no uterus on pelvic ultrasound. Her karyotype is 46,XY. [7] [3]

a) What is the most likely diagnosis, and which pathophysiological mechanism explains both the normal breast development and the absent uterus? (3 marks) [7]

b) Outline the investigation that confirms the diagnosis and the counselling of the adolescent and family, including the timing and manner of disclosure. (3 marks) [3]

c) State the long-term management, including the decision around the intra-abdominal gonad and the hormone replacement. (2 marks) [7]

d) Explain how the 2006 Chicago consensus reframed the terminology and the classification of this group of conditions, and why the language used with the family matters. (2 marks) [1] [3]