Reproductive Endocrinology Practice Questions

Q: A tall adolescent presents with primary amenorrhea. On examination, she has normal breast development, absent axillary and pubic hair, and an inguinal hernia. What is the probable diagnosis?

Androgen insensitivity syndrome. ### Explanation The clinical presentation points toward **Androgen Insensitivity Syndrome (AIS)**, specifically the complete form. **1. Why Androgen Insensitivity Syndrome (AIS) is correct:** AIS is an X-linked recessive condition where a genotypic male (46, XY) has a functional mutation in the androgen receptor. * **Breast development:** Occurs because the testes produce testosterone, which is peripherally converted to estrogen (aromatization). * **Absent hair:** Axillary and pubic hair growth is dependent on androgen action; since receptors are non-functional, hair is absent or sparse. * **Inguinal hernia:** This is a classic sign in AIS, representing the undescended testes (cryptorchidism) located in the inguinal canal. * **Tall stature:** Due to the presence of the Y chromosome and the lack of androgen-mediated epiphyseal closure. **2. Why other options are incorrect:** * **Complete Gonadal Dysgenesis (Swyer Syndrome):** These patients have a 46, XY karyotype but streak gonads. They lack estrogen, so they present with **no breast development** (sexual infantilism). * **MRKH Syndrome:** These are genotypic females (46, XX) with normal ovaries. They have **normal pubic and axillary hair** because their androgen receptors function normally. * **Congenital Adrenal Hyperplasia (CAH):** This typically presents with ambiguous genitalia and **virilization** (excess hair/clitoromegaly) in females, not normal breast development with absent hair. **3. NEET-PG High-Yield Pearls:** * **AIS vs. MRKH:** The most common "differentiating" factor in exams is **hair distribution** (Absent in AIS, Normal in MRKH) and **Karyotype** (46, XY in AIS, 46, XX in MRKH). * **Management of AIS:** Gonadectomy is performed **after puberty** to allow for natural breast development (via aromatization), followed by estrogen replacement to prevent osteoporosis. * **Vagina:** In both AIS and MRKH, the vagina is a short, blind-ended pouch.

Q: A 10-year-old girl presents with primary amenorrhea, widely spaced nipples, and streak-like gonads. What is the most likely diagnosis?

Turner's syndrome. ### Explanation **Correct Answer: B. Turner’s Syndrome** **Why it is correct:** Turner’s Syndrome (45,XO) is the most common cause of primary amenorrhea and hypergonadotropic hypogonadism. The clinical triad presented—**primary amenorrhea, widely spaced nipples (shield chest), and streak gonads**—is classic. Streak gonads occur because the absence of the second X chromosome leads to accelerated oocyte atresia, replacing functional ovarian tissue with fibrous stroma. This results in low estrogen and high FSH levels. **Why the other options are incorrect:** * **A. MRKH Syndrome:** Characterized by Müllerian agenesis (absent uterus and upper vagina). These patients have **normal ovaries** and normal secondary sexual characteristics (46,XX), unlike the streak gonads seen here. * **C. Swyer Syndrome:** This is 46,XY gonadal dysgenesis. While it presents with streak gonads and primary amenorrhea, patients are typically **tall** and do not exhibit the classic stigmata of Turner’s (like shield chest or short stature). * **D. Mixed Gonadal Dysgenesis:** Usually presents with a mosaic karyotype (45,X/46,XY) and **ambiguous genitalia**, which is not mentioned in this case. **High-Yield NEET-PG Pearls:** * **Most common karyotype:** 45,XO (Monosomy X). * **Short Stature:** The most consistent clinical finding (due to SHOX gene deficiency). * **Cardiac Association:** Bicuspid aortic valve (most common) and Coarctation of the aorta. * **Renal Association:** Horseshoe kidney. * **Diagnosis:** Gold standard is **Chromosomal Karyotyping**. * **Management:** Growth hormone for height; Estrogen/Progesterone for secondary sexual characteristics and bone health.

Q: What is the investigation of choice to differentiate Mullerian agenesis from testicular feminization syndrome in a case of primary amenorrhea?

Karyotype. In a patient presenting with primary amenorrhea, normal breast development, and an absent uterus, the two primary differentials are **Mullerian Agenesis (MRKH Syndrome)** and **Androgen Insensitivity Syndrome (Testicular Feminization)**. ### Why Karyotype is the Investigation of Choice The definitive differentiation between these two conditions lies in the genetic sex: * **Mullerian Agenesis:** The patient is a genotypic female (**46, XX**) with normal ovaries. The defect is a failure of Mullerian duct development. * **Androgen Insensitivity Syndrome:** The patient is a genotypic male (**46, XY**) with undescended testes. The defect is a mutation in the androgen receptor, leading to a female phenotype despite male genetics. ### Why Other Options are Incorrect * **Ultrasound (USG):** While USG can confirm the absence of a uterus and identify ovaries/testes, it is not definitive. Ovaries and undescended testes can sometimes look similar on imaging. * **Laparoscopy:** This is an invasive procedure. While it can visualize internal anatomy, it is no longer the "investigation of choice" when non-invasive genetic testing is available. * **Hormonal Assays:** Serum testosterone levels are high (male range) in AIS and low (female range) in MRKH. However, **Karyotyping** remains the gold standard for definitive diagnosis and management planning (e.g., timing of gonadectomy in AIS). ### High-Yield Clinical Pearls * **Pubic/Axillary Hair:** Present in MRKH (adrenarche is normal); **Absent or scanty** in AIS (due to androgen resistance). * **Gonads:** Ovaries are present in MRKH (normal ovulation/hormones); Testes are present in AIS (risk of malignancy/dysgerminoma). * **Testosterone Levels:** In AIS, testosterone is in the **normal male range**, but the body cannot respond to it.

Q: A 16-year-old female presents with primary amenorrhea. Examination shows a short, blind vagina with an absent uterus. What is the next investigation of choice?

Karyotyping. **Explanation:** The clinical presentation of primary amenorrhea with a **blind vagina and absent uterus** points toward two primary differential diagnoses: **Müllerian Agenesis (Mayer-Rokitansky-Küster-Hauser syndrome)** and **Complete Androgen Insensitivity Syndrome (CAIS)**. 1. **Why Karyotyping is the Correct Answer:** Karyotyping is the definitive investigation to differentiate between these two conditions. * In **MRKH**, the karyotype is **46,XX** (female), ovaries are functional, and secondary sexual characteristics are normal. * In **CAIS**, the karyotype is **46,XY** (male). The patient has undescended testes which must be surgically removed after puberty due to the high risk of malignancy (gonadoblastoma/dysgerminoma). Therefore, determining the genetic sex is the crucial next step for management. 2. **Why Other Options are Incorrect:** * **Intravenous Pyelogram (IVP):** While renal anomalies are common in MRKH (up to 30-40%), an IVP or Renal USG is performed *after* the diagnosis is established, not as the initial differentiating tool. * **Gonadotropin levels (FSH/LH):** These are typically normal in both MRKH and CAIS (as both have functioning gonads—ovaries and testes respectively). They are more useful in diagnosing premature ovarian failure or central causes of amenorrhea. * **Serum Prolactin:** This is used to rule out hyperprolactinemia, which presents with secondary amenorrhea or primary amenorrhea *with* a present uterus. **High-Yield Clinical Pearls for NEET-PG:** * **MRKH:** 46,XX; Normal female testosterone levels; Ovaries present; Associated with renal/skeletal (VACTERL) anomalies. * **CAIS:** 46,XY; Male testosterone levels (but body is insensitive); Absent/scant pubic and axillary hair; Testes present (usually inguinal). * **Initial Investigation:** Ultrasound (to confirm absent uterus). * **Next/Confirmatory Investigation:** Karyotyping.

Q: In a girl with sexual infantilism and defective smell sensation, which of the following is the likely diagnosis transmitted by the sex chromosome?

Kallman's syndrome. ### Explanation **Kallmann’s Syndrome** is the correct diagnosis based on the classic clinical dyad of **hypogonadotropic hypogonadism** (leading to sexual infantilism/delayed puberty) and **anosmia or hyposmia** (defective smell). 1. **Why it is correct:** The condition results from the failure of GnRH-secreting neurons and olfactory neurons to migrate from the olfactory placode to the hypothalamus. While it can be autosomal dominant or recessive, the most classic form (KAL1 gene mutation) is **X-linked recessive**, satisfying the "transmitted by sex chromosome" criteria in the question. 2. **Why the others are incorrect:** * **Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome:** Characterized by Müllerian agenesis (absent uterus/upper vagina). These patients have normal ovaries, normal secondary sexual characteristics (not infantilism), and a normal sense of smell. * **Androgen Insensitivity Syndrome (AIS):** These are genotypic males (46,XY) with a female phenotype. They have breast development (due to peripheral aromatization) but absent pubic hair. They do not have anosmia. * **McCune-Albright Syndrome:** Presents with a triad of **precocious puberty** (not infantilism), café-au-lait spots, and polyostotic fibrous dysplasia. ### NEET-PG High-Yield Pearls * **Gold Standard Diagnosis:** MRI of the brain (shows absent or hypoplastic olfactory bulbs). * **Hormonal Profile:** Low GnRH → Low FSH/LH → Low Estrogen (Hypogonadotropic Hypogonadism). * **Associated Features:** Color blindness, cleft lip/palate, and renal agenesis (especially in the X-linked form). * **Treatment:** Pulsatile GnRH therapy is used to induce ovulation/fertility; HRT is used for the development of secondary sexual characteristics.

Question 1

Withdrawal bleeding occurs when progestin is administered continuously?

Accepted Answer

Estrogen concentration is sufficient

Answer

Structural abnormality in the pelvis

Answer

Associated with endocrine disorder

Answer

Atrophic endometrium

Question 2

A tall adolescent presents with primary amenorrhea. On examination, she has normal breast development, absent axillary and pubic hair, and an inguinal hernia. What is the probable diagnosis?

Accepted Answer

Androgen insensitivity syndrome

Answer

Complete gonadal dysgenesis

Answer

Mayer-Rokitansky-Küster-Hauser syndrome

Answer

Congenital adrenal hyperplasia

Question 3

A 10-year-old girl presents with primary amenorrhea, widely spaced nipples, and streak-like gonads. What is the most likely diagnosis?

Accepted Answer

Turner's syndrome

Answer

MRKH syndrome

Answer

Swyer syndrome

Answer

Mixed gonadal dysgenesis

Question 4

What is the investigation of choice to differentiate Mullerian agenesis from testicular feminization syndrome in a case of primary amenorrhea?

Accepted Answer

Karyotype

Answer

Ultrasound (USG)

Answer

Laparoscopy

Answer

Hormonal assays

Question 5

Vaginal cytology for hormonal changes are best taken from which location?

Accepted Answer

Lateral wall

Answer

Posterior wall

Answer

Anterior wall

Answer

Any wall

Question 6

What are the levels of progesterone indicating an unruptured follicle and a ruptured intrauterine pregnancy?

Accepted Answer

5 ng/ml; 20 ng/ml

Answer

10 ng/ml; 20 ng/ml

Answer

5 ng/ml; 50 ng/ml

Answer

10 ng/ml; 50 ng/ml

Question 7

A 16-year-old female presents with primary amenorrhea. Examination shows a short, blind vagina with an absent uterus. What is the next investigation of choice?

Accepted Answer

Karyotyping

Answer

Intravenous pyelogram (IVP)

Answer

Gonadotropin levels

Answer

Serum prolactin

Question 8

Increased capillary permeability in Ovarian Hyperstimulation Syndrome (OHSS) is due to all except:

Accepted Answer

Inhibin

Answer

Vascular endothelial growth factor

Answer

Angiotensin II

Answer

Oestrogen

Question 9

In a girl with sexual infantilism and defective smell sensation, which of the following is the likely diagnosis transmitted by the sex chromosome?

Accepted Answer

Kallman's syndrome

Answer

Rokitansky-Kuster-Hauser syndrome

Answer

Androgen insensitivity syndrome

Answer

McCune-Albright syndrome

Question 10

A 20-year-old female presents for an infertility workup. She has never had a menstrual period. She is short with a broad chest, webbed neck, and low-set ears. It is demonstrated that she has an abnormal karyotype. What is the cause of the woman's abnormal karyotype?

Accepted Answer

Either maternal or paternal nondisjunction

Answer

Maternal nondisjunction

Answer

Paternal nondisjunction

Answer

Both maternal and paternal nondisjunction

Reproductive Endocrinology — MCQs

Reproductive Endocrinology — MCQs

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