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 monitoring 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]}