Congenital Anomalies of the GU Tract - Donohue/Kryger Flashcards
Give some general features of undervirilized males
- small phallus
- hypospadias
- cryptorchism
- bifid scrotum
- absence of scrotal rugation
Give some general features of virilized females
- clitoromegaly
- common urogenital sinus
- fused labioscrotal folds
- rugated labioscrotal folds
What is 46 XX DSD? What causes it?
What is the most common etiology of 46 XX DSD?
Give some other causes
Ovaries are present, but external genitalia are virilized or ambiguous. Occurs due to excessive and inappropriate exposure to androgens during early gestation.
Excessive fetal androgen production due to congenital adrenal hyperplasia due to 21-hydroxylase deficiency
Other causes include: excessive maternal androgens (virilizing tumors), maternal drugs (exogenous androgens), presence of SRY sequences on X chromosome
What is 46 XY DSD? What causes it?
What is the most common etiology?
What other causes/associations does 46 XY DSD have?
Testes are present, but external genitalia are female or ambiguous
Idiopathic (lecture) or **androgen insensitivity syndrome **(first aid)
Other causes include:
- Genetic defects in testicular differentiation: SRY, X-loci, autosomes
- Defects in sertoli cell function (inadequate MIS) -> persistence of mullerian ducts
- Defects in leydig cell function: testosterone defect, LH/hCG response defect
- Defects in DHT production
- Gonadal dysgenesis
- Congenital adrenal hyperplasia
What is ovotesticular DSD?
What is the most common karyotype?
Describe the makeup of the gonads in this disorder
Describe the external genitalia observed in this disorder
Describe the internal genitalia observed in this disorder
Both ovarian and testicular tissue are present
46XX (70%)
Gonads: many combinations - ovotestes, testis on one side and ovary on the other, etc
External genitalia: variable (fem <-> male)
Internal genitalia: parallels the ipsilateral gonad
Is fertility common with ovotesticular DSD?
No. Fertility is uncommon.
What should you consider working up a child for DSD?
When any of the following are present:
- Whenever the genitalia do not look completely normal
- Bilateral nonpalpable gonads
- Severe hypospadias with or without nonpalpable gonads
- Clitoromegaly or microphallus
- Posterior fusion of the vaginal opening or undervirilized scrotum
Explain why DSD should still be on your differential for each of the following:
- Cryptorchism
- Clitoromegaly
- Hypospadias
- Unambiguous external sexual phenotype
- Don’t assume cryptorchism because the child could be female (ovaries are in the abdomen where they belong)
- Don’t assume clitoromegaly when it could be microphallus (i.e. the child is actually male)
- Don’t assume hypospadias when it could be a female urethral opening (i.e. the child is actually female)
- Don’t assume you know the karytype of the child based on normal-looking external sexual characteristics (i.e. androgen insensitivity syndrome - see House, MD S2E13 for an example of this)
And, because this doesn’t fit anywhere else: avoid calling the baby he/she until gender assignment is decided upon
A female adolescent undergoes surgical repair of an apparent inguinal hernia. To the surgeon’s surprise, he finds a testicle in the inguinal canal. WTF? Explain.
This child likely has CAIS (complete androgen insensitivity syndrome). She is karyotypically male but shows a complete female phenotype (sans pubic hair and menses) due to lack of any androgen response.
Compare CAIS to PAIS in terms of phenotype
(complete androgen insensitivity syndrome vs. partial androgen insensitivity syndrome)
CAIS: otherwise phenotypically normal female with primary amenorrhea and absent pubic hair
PAIS: highly variable - from ambiguous genitalia (most common) to normal male (with infertility). Gynecomastia and microphallus are often observed.
CAIS
- Type of gonads formed
- Androgen production
- Wolffian duct status
- MIS production
- Mullerian duct status
- External genitalia
- Course of puberty
- Testes
- Produces androgens, no response
- Wolffian ducts regress
- MIS produced
- Mullerian ducts do not develop
- Femal external genitalia
- Feminizing puberty w/o menses
Why is PAIS especially frustrating to both the patient and the clinician?
Clinician: gender assignment may be difficult - variable phenotype spectrum may make constructing functional genitalia difficult. Predicting gender identity satisfaction is also difficult.
Patient: though most are ultimately satisfied with gender assignment, most are ultimately unsatisfied with genital appearance and/or functionality.
Complete testosterone biosynthetic defect (karyotype 46XY):
- gonad type?
- androgen production?
- Wolffian duct status?
- MIS production
- Mullerian duct status?
- External genitalia type
- Puberty?
- testes
- no androgen production (due to enzyme deficiency)
- wolffian ducts regress
- MIS is produced
- mullerian ducts regress
- female external genitalia
- feminizing puberty (if given estrogen therapy)
What hormone is most important to virilization prior to birth?
At puberty?
DHT
Testosterone
5-alpha reductase deficiency:
- gonad type?
- androgen production?
- Wolffian duct status?
- MIS production
- Mullerian duct status?
- External genitalia type
- Puberty?
- testes
- produces androgens
- wolffian ducts develop
- MIS produced
- Mullerian ducts regress
- male external genitalia
- masculinizing puberty
