What is polycystic ovary syndrome?
Polycystic ovary syndrome (PCOS) is a complex condition. It is a true syndrome in that there is no single diagnostic criterion essential to making the diagnosis. It has a wide spectrum of presentations, including typical and non-typical patients.
The Rotterdam criteria are frequently referred to as ‘providing the benchmark for making the diagnosis’. Two out of three of the following are required:
- oligomenorrhoea (infrequent periods) or anovulation
- clinical and/or biochemical evidence of hyperandrogenism (this means excessive testosterone hormone)
- polycystic ovaries seen on ultrasound scanning
One of the many controversies about PCOS is whether it should be regarded as a metabolic disorder, characterised by insulin resistance, or whether it should primarily be regarded as being a reproductive disorder of hypothalamic /ovarian disfunction.
Overall, PCOS affects between 4-12% of women. There are broadly two types of PCOS. Firstly, PCOS women who are not overweight – this type of PCOS is probably genetic in origin and this is witnessed by the fact that there is an increased risk amongst monozygotic (identical) twins. The other main type of PCOS is what is called the acquired form of PCOS and typically these women will be overweight to the point of being medically obese. The physical signs of PCOS are excessive body hair growth (this is assessed medically using the Ferriman and Gallwey score and also the Lorenzo score. There can be loss of hair on the head, not the male pattern baldness type but more loss of hair on the crown and this can be assessed using the Ludwig scale. Some women will complain of sunburn on top of their head.
On transvaginal ultrasound the ovaries can look normal, but more typically they have a PCOS appearance. Typically the ovaries are enlarged to 8-10mls or more, with increased stromal thickening (this means the central part of the ovary does not have any follicles) and there are a number of small follicles around the edge of the ovary. This appearance is sometimes described as a string-of-pearls. These tiny follicles or cysts around the edge the ovary are due to eggs that have started to mature, and then have stopped developing; they are know as atretic follicles. Rather confusingly, women who have PCOS but have normal ovaries are sometimes referred to as being PCOS but without polycystic ovaries.
The laboratory investigations which are relevant are testosterone and, if this is elevated, to measure dehydroepiandrosterone sulphate (this is the male type hormone produced by the adrenal glands). The main pituitary hormones are prolactin, thyroid stimulating hormone (TSH), follicle stimulating hormone (FSH) and luteinising hormone (LH). Ideally these blood samples should be taken between days 2-5 of the menstrual cycle. If the LH level is higher than the FSH level, this is called a reverse ratio and is a typical but not essential feature of PCOS. A hormone called 17-hydroxyprogesterone is also worth measuring – this is a screening test for a condition called congenital adrenal hyperplasia. The protein that binds testosterone in the circulation is called sex hormone-binding globulin (SHBG) and if this is measured along with the testosterone, it is possible to work out how much of the testosterone is likely to bound and how much is likely to be free.
When a number of possible diagnoses need to be considered, the medical term is differential diagnosis. Medical conditions that can present in the same way as PCOS include:
- Congenital adrenal hyperplasia
- Cushing’s syndrome
- Androgen secreting tumour
- Exogenous sex steroids
- Hyperprolactinaemia
- Simple obesity
- Severely insulin resistant status
With regards to Cushing’s syndrome, these patients can present with fractures. The onset of the disease can be quite slow, often referred to as indolent and here old photographs can help to note the change in a woman’s appearance. Symptoms which can be present with Cushing’s syndrome, which are absent in PCOS, include personality changes, a tendency to bruise and a weakness of the muscles called proximal myopathy. When this happens patients have to push up to sit up. It is also associated with high blood pressure and laboratory tests show an increase in the urine free cortisol and an abnormal response to the dexamethasone suppression test.
Two unusual and not well known associations with PCOS are an increased tendency to smoke and an increased tendency to use alcohol. One study showed that 40% of PCOS women had smoked at some point in their lives and that 67% had used alcohol.
To find out more about the issues surrounding PCOS, including strategies for coping with different aspects of the disease Click Here