PCOS (Polycystic Ovary Syndrome) – Top USMLE Diseases

Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder of reproductive-age women, affecting nearly 5%‒10% of women in the age group. Characterized by hyperandrogenism, chronic anovulation leading to oligomenorrhea (or amenorrhea), and metabolic dysfunction, PCOS increases a woman’s risk for infertility, endometrial hyperplasia or carcinoma, and cardiovascular disease. The pathophysiology is incompletely understood but thought to have a multifactorial genetic basis causing altered pulsatile release of gonadotropin-releasing hormone (GnRH), as well as increases in luteinizing hormone (LH), androgens, estrogen, and insulin: The result is chronic anovulation and hirsutism, which define the condition. Diagnosis is one of exclusion; therefore, other causes of abnormal uterine bleeding and hirsutism must be ruled out. Management includes attempting to restore normal ovulation through weight loss, oral contraceptive pills (OCPs), and fertility assistance.

Ovarian cysts are defined as collections of fluid or semiliquid material, often walled off by a membrane, located in the ovary. These cysts are broadly categorized as either neoplastic or nonneoplastic. Neoplastic ovarian cysts are subcategorized as either benign or malignant and classified according to their cell of origin. Nonneoplastic cysts are benign and include functional cysts (such as follicular and corpus luteal cysts, which result from normal physiologic processes), hemorrhagic cysts, and endometriomas. In women of reproductive age, neoplastic ovarian cysts are typically benign; however, the risk of malignancy increases in the postmenopausal period. While most ovarian cysts do not cause symptoms, some women report vague symptoms such as lower abdominal pain or abdominal fullness. Complications of cysts include torsion and rupture. Treatment is dependent on the etiology of the ovarian cyst and may range from surgical intervention to supportive care only.

Imaging of the internal female reproductive organs (including the uterus, ovaries, and fallopian tubes) is indicated to diagnose common gynecologic complaints, most commonly in cases of abnormal bleeding, pelvic pain, and to evaluate masses, congenital anomalies, and infertility. Ultrasound is almost always the 1st-line imaging modality of choice, whereas MRI is typically reserved for complicated or indeterminate cases as a follow-up. Computed tomography is almost never used for primary gynecologic assessments. Fallopian tubes are not visible on either ultrasound or MRI if they are normal. The best way to assess tubal patency is by using hysterosalpingography, a fluoroscopic exam in which a dye is injected into the uterine cavity, followed by the study of its flow through the fallopian tubes.

Ovaries are the paired gonads of the female reproductive system that contain haploid gametes known as oocytes. The ovaries are located intraperitoneally in the pelvis, just posterior to the broad ligament, and are connected to the pelvic sidewall laterally by the suspensory ligament of the ovary and to the uterus medially by the utero-ovarian ligament. These organs function to secrete hormones (estrogen and progesterone) and to produce the female germ cells (oocytes), which are expelled and then “captured” by the uterine tubes. The primary blood supply to the ovary is provided by the ovarian artery, a direct branch of the abdominal aorta; the ovarian artery anastomoses with the ascending branch of the uterine artery, providing excellent collateral blood flow.

Klinefelter syndrome is a chromosomal aneuploidy characterized by the presence of 1 or more extra X chromosomes in a male karyotype, most commonly leading to karyotype 47,XXY. Klinefelter syndrome is associated with decreased levels of testosterone and is the most common cause of congenital hypogonadism. Symptoms are often not noticed until adolescence or adulthood. Individuals with this condition tend to present as tall, phenotypic men with small testes, decreased body hair, gynecomastia, and infertility. Treatment consists of life-long testosterone replacement therapy.

Ovarian cysts are defined as collections of fluid or semiliquid material, often walled off by a membrane, located in the ovary. These cysts are broadly categorized as either functional or neoplastic. Neoplastic ovarian cysts are subcategorized as either benign or malignant. When the cysts occur as a result of normal physiologic processes, they are called functional, whereas if there is abnormal growth of ovarian cells, the cyst is referred to as neoplastic. In women of reproductive age, neoplastic ovarian cysts are typically benign; however, the risk of malignancy increases in the postmenopausal period. While most ovarian cysts do not cause symptoms, some women report vague symptoms such as lower abdominal pain or abdominal fullness. Complications of functional cysts include torsion and rupture. Neoplastic cysts may be either benign or cancerous. A diagnosis of ovarian cancer requires consultation with a specialist because treatment involves coordination of surgery and chemotherapy. Treatment is dependent on the etiology of the ovarian cyst and may range from surgical intervention to supportive care only.

Androgen insensitivity syndrome (AIS) is an X-linked recessive condition in which a genetic mutation affects the function of androgen receptors, resulting in complete (CAIS), partial (PAIS), or mild (MAIS) resistance to testosterone. All individuals with AIS have a 46,XY karyotype; however, phenotypes vary and include phenotypic female, virilized female, undervirilized male, and phenotypic male individuals. Androgen insensitivity syndrome always leads to infertility. Hormone analysis, imaging, and genetic testing help make the diagnosis. Management of AIS varies depending on the degree of androgen sensitivity, phenotype, and gender identity, and may involve hormone-replacement therapy and surgery to correct anatomical anomalies of the reproductive and genital structures.

Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder of reproductive-age women, affecting nearly 5%‒10% of women in the age group. Characterized by hyperandrogenism, chronic anovulation leading to oligomenorrhea (or amenorrhea), and metabolic dysfunction, PCOS increases a woman’s risk for infertility, endometrial hyperplasia or carcinoma, and cardiovascular disease. The pathophysiology is incompletely understood but thought to have a multifactorial genetic basis causing altered pulsatile release of gonadotropin-releasing hormone (GnRH), as well as increases in luteinizing hormone (LH), androgens, estrogen, and insulin: The result is chronic anovulation and hirsutism, which define the condition. Diagnosis is one of exclusion; therefore, other causes of abnormal uterine bleeding and hirsutism must be ruled out. Management includes attempting to restore normal ovulation through weight loss, oral contraceptive pills (OCPs), and fertility assistance.