It is vital to note that not all women with PCOS have polycystic ovaries, nor do all women with ovarian cysts have PCOS; although a pelvic ultrasound is a major diagnostic tool, it is not the only one. Diagnosis can be difficult, particularly because of the wide range of symptoms, and the variability of how they present themselves in individuals (which is why this disorder is characterized as a syndrome rather than a disease). There is a lot of controversy about the appropriate testing:
* gynecologic ultrasonography
* testosterone: free more sensitive than total
* Fasting biochemical screen and lipid profile
* 2-hour oral glucose tolerance test (GTT) in patients with risk factors (obesity, family history, history of gestational diabetes)
* For exclusion purpose:
o Prolactin
o TSH
o 17-OH-progesterone
The role of other tests is more controversial, including:
* fasting insulin level or GTT with insulin levels (also called IGTT)
* LH:FSH ratio
* DHEAS
* SHBG
* Androstenedione
Differential diagnosis
As well, other causes of irregular/absent menstruation and hirsutism such as congenital adrenal hyperplasia, Cushing’s syndrome, hyperprolactinemia and other pituitary and/or adrenal disorders, should be investigated.
Pathogenesis
PCOS develops when the ovaries are stimulated to produce excessive amounts of male hormones (androgens), particularly testosterone – either through the release of excessive luteinizing hormone (LH) by the pituitary gland, or due to high levels of insulin in the blood (hyperinsulinaemia) in women whose ovaries are sensitive to this stimulus.
This syndrome acquired its most widely-used name because a common symptom is multiple (poly) ovarian cysts. These form where egg follicles matured, but were never released from the ovary due to abnormal hormone levels. These generally take on a ’string of pearls’ appearance. The condition was first described in 1935 by Dr. Stein and Dr. Leventhal, hence its original name of Stein-Leventhal syndrome.
Although the cause of PCOS is not known, research to date suggests that it may be a genetically-linked condition, and further research into this possibility is currently taking place. No specific gene has been identified, and it is thought that there are many genes that could contribute to the development of PCOS.
A majority of patients with PCOS -some investigators may say all – have insulin resistance. Their increased insulin levels contribute to or cause the abnormalities seen in the hypothalamic-pituitary-ovarian axis that lead to PCOS. Specifically hyperinsulinemia increases GnRH pulse frequency, LH over FSH dominance, increased ovarian androgen production, decreased follicular maturation, and decreased SHBG binding: all these steps leading to the development of PCOS.
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