Ambiguous genitalia

Question 1

Ix for ambiguous genetalia (2)

Answer 1

buccal smear: barr bodies suggest female
WBC mustard stains make y chromosomes fluoresce

phallus+barr bodies=androgenital syndrome/maternal androgens or true hemaphroditism
phallus+male buccal smear=boy

Question 2

Causes of ambiguous genetalia (4)

Answer 2

CAH
androgen insensitivity syndrome
5-alphareductase deficiency (male genitals develop to varying degree)
mosaicism (variably XX/XY/other)

Question 3

Features of CAH (3)

Answer 3

auto-R
90% salt wasting(no aldosterone):21-hydroxylase deficiency, needed to make cortisol> raised ACTH>raised androgens
10% salt sparing: 17-alpha-hydroxylase deficiency, can still produce aldosterone

Question 4

Presentation of salt-wasting CAH

Answer 4

in XX: ambiguous genetalia, cliteromegaly, fused labia
in XY: large penis, darkened scrotum
salt loss crisis:
-1-3wks post-partum
-present w. vomitting, wt. loss, circulatory collapse and floppiness
-Rx w. IV saline, hydrocortisone and fludrocortisone

Question 5

Ix for CAH and blood test results (7)

Answer 5

raised 17-OHP (hydroxyprogesterone)
raised 21-deoxycortisol levels
decreased urinary adrenocorticosteroid metabolites
Blood tests:
-hyponatraemia
-hyperkalaemia
-metabolic acidosis
-hypoglycaemia

Question 6

Mx of CAH (4)

Answer 6

cortisol replacement-hydrocortisone as it doesn’t stunt growth (raise dose when sick)
fludrocortisone for salt wasting
urogenital surgery-clitoral reduction, vaginoplasty
monitor wt. and growth

Question 7

Features of androgen insensitivity syndrome (4)

Answer 7

looks like vagina on outside
blind-ended pouch
no ovaries and uterus
boys express MIF (mullerian inhibitory factor) to prevent development of female genetalia