Polycystic Ovarian Syndrome:
Polycystic ovarian syndrome (PCOS) is one of the most common female endocrine disorders. Polycystic Ovarian Syndrome is a complex, heterogeneous disorder of uncertain etiology. Both genes and the environment contribute to Polycystic Ovarian Syndrome. Obesity, exacerbated by poor dietary choices and physical inactivity, worsens Polycystic Ovarian Syndrome in susceptible individuals. It is thought to be one of the leading causes of female subfertility and the most frequent endocrine problem in women of reproductive age.
The principal features are anovulation, resulting in irregular menstruation, amenorrhea, ovulation-related infertility, and polycystic ovaries; excessive amounts or effects of androgenic hormones, resulting in acne and hirsutism; and insulin resistance, often associated with obesity, Type 2 diabetes, and high cholesterol levels.The symptoms and severity of the syndrome vary greatly among affected women.
Signs and symptoms of Polycystic Ovarian Syndrome:
Some common symptoms of Polycystic Ovarian Syndrome include:
- Menstrual disorders: Polycystic Ovarian Syndrome mostly produces oligomenorrhea or amenorrhea, but other types of menstrual disorders may also occur.
- Infertility: This generally results directly from chronic anovulation (lack of ovulation).
- Hyperandrogenism: The most common signs are acne and hirsutism (male pattern of hair growth), but it may produce hypermenorrhea (very frequent menstrual periods) or other symptoms. Approximately three-quarters of patients with Polycystic Ovarian Syndrome (by the diagnostic criteria of NIH/NICHD 1990) have evidence of hyperandrogenemia.
- Metabolic syndrome: This appears as a tendency towards central obesity and other symptoms associated with insulin resistance. Serum insulin, insulin resistance and homocysteine levels are higher in women with Polycystic Ovarian Syndrome.
Pathogenesis of Polycystic Ovarian Syndrome:
Polycystic ovaries develop when the ovaries are stimulated to produce excessive amounts of male hormones (androgens), particularly testosterone, by either one or a combination of the following (almost certainly combined with genetic susceptibility):
- The release of excessive luteinizing hormone (LH) by the anterior pituitary gland
- Through high levels of insulin in the blood (hyperinsulinaemia) in women whose ovaries are sensitive to this stimulus
Alternatively or as well, reduced levels of sex-hormone binding globulin can result in increased free androgens.
The syndrome acquired its most widely used name due to the common sign on ultrasound examination of multiple (poly) ovarian cysts. These “cysts” are actually immature follicles, not cysts (“polyfollicular ovary syndrome” would have been a more accurate name). The follicles have developed from primordial follicles, but the development has stopped (“arrested”) at an early antral stage due to the disturbed ovarian function. The follicles may be oriented along the ovarian periphery, appearing as a ‘string of pearls’ on ultrasound examination. There is also an increase in volume of ovary, especially due to increase in stroma.
Women with Polycystic Ovarian Syndrome have higher GnRH, which in turn results in an increase in LH/FSH ratio.
A majority of patients with Polycystic Ovarian Syndrome have insulin resistance and/or are obese. Their elevated insulin levels contribute to or cause the abnormalities seen in the hypothalamic-pituitary-ovarian axis that lead to Polycystic Ovarian Syndrome. Hyperinsulinemia increases GnRH pulse frequency, LH over FSH dominance, increased ovarian androgen production, decreased follicular maturation, and decreased SHBG binding; all these steps contribute to the development of Polycystic Ovarian Syndrome. Insulin resistance is a common finding among patients of normal weight as well as overweight patients.
Differential diagnosis of Polycystic Ovarian Syndrome:
Other causes of irregular or absent menstruation and hirsutism, such as hypothyroidism, congenital adrenal hyperplasia (21-hydroxylase deficiency), Cushing’s syndrome, hyperprolactinemia, androgen secreting neoplasms, and other pituitary or adrenal disorders, should be investigated. Polycystic Ovarian Syndrome has been reported in other insulin-resistant situations such as acromegaly.