A 15-year-old girl is brought to the office due to absent menstruation. Her sister and mother attained menarche at 13, and she wants to know when she will start her menstrual period. The patient has asthma and takes albuterol as needed for cough or wheeze. She was hospitalized at age 2 for pneumonia. The patient is on the varsity track team and is a C+ student. Height and weight are at the 60th percentile. Vital signs are normal. Physical examination shows Tanner stage IV breast development and pubic hair, normal external female genitalia, and shaved axillary hair. Pelvic ultrasonography shows 2 normal-sized ovaries but no uterus. Which of the following is the most likely cause of this patient's condition?

Question

A 15-year-old girl is brought to the office due to absent menstruation.  Her sister and mother attained menarche at 13, and she wants to know when she will start her menstrual period.  The patient has asthma and takes albuterol as needed for cough or wheeze.  She was hospitalized at age 2 for pneumonia.  The patient is on the varsity track team and is a C+ student.  Height and weight are at the 60th percentile.  Vital signs are normal.  Physical examination shows Tanner stage IV breast development and pubic hair, normal external female genitalia, and shaved axillary hair.  Pelvic ultrasonography shows 2 normal-sized ovaries but no uterus.  Which of the following is the most likely cause of this patient's condition?

Quizplus · Accepted Answer

11ec25c8_d66a_247d_bc81_ebb5d6871321_MD0003_00 This patient's primary amenorrhea, normal secondary sexual characteristics, and absent uterus are consistent with Müllerian agenesis (Mayer-Rokitansky-Küster-Hauser syndrome), the failure of Müllerian duct development. The Müllerian duct develops into the uterus, cervix, and upper third of the vagina. Patients with agenesis do not develop these structures, so amenorrhea is typically the presenting symptom. Müllerian duct development does not affect ovarian development; therefore, patients have normal estrogen levels and normal secondary sexual characteristics (eg, breasts, normal stature). In addition, the external genitalia develop from a different precursor (ie, genital tubercle), so patients have normal female external genitalia and lower two-thirds of the vagina (ie, blind vaginal pouch, vaginal dimple). (Choice A) Patients with androgen insensitivity syndrome, a complete defect in androgen receptor function, are phenotypically female and have primary amenorrhea due to an absent uterus. However, patients with this syndrome have no pubic or axillary hair due to a defective androgen receptor, making this diagnosis unlikely. (Choice B) Turner syndrome, the congenital absence of an X chromosome, can present with primary amenorrhea due to gonadal dysgenesis. However, patients lack breast development and have a short stature and a uterus. (Choice C) Cystic fibrosis, caused by a transmembrane conductance regulator gene defect, can cause pubertal delay (secondary to malnutrition) and infertility (due to abnormal cervical mucus). There is no association with an absent uterus. (Choice D) Patients with 5-alpha-reductase deficiency, impaired conversion of testosterone to dihydrotestosterone, initially have female external genitalia and male internal genitalia (ie, undescended testes) until puberty. At puberty, patients undergo virilization (eg, muscle growth, voice deepening) due to increased levels of testosterone. (Choice F) GnRH deficiency can present with primary amenorrhea. However, the low GnRH causes low estrogen levels, which prevents the development of secondary sexual characteristics. It does not affect uterine development. Educational objective: Müllerian agenesis, failure of Müllerian duct development, causes an absent uterus, cervix, and upper third of the vagina (ie, blind vaginal pouch). Müllerian agenesis does not affect ovarian or external genital development. Therefore, patients have primary amenorrhea with associated normal female external genitalia and secondary sexual characteristics. References: ACOG committee opinion no. 728: Müllerian agenesis: diagnosis, management, and treatment. (http://www.ncbi.nlm.nih.gov/pubmed/29266078) Amenorrhea: an approach to diagnosis and management. (http://www.ncbi.nlm.nih.gov/pubmed/23939500)

A 15-Year-Old Girl Is Brought to the Office Due to Absent