PCOS_Flashcards
What is Polycystic Ovary Syndrome (PCOS)?
PCOS is a complex condition of ovarian dysfunction affecting 5-20% of women of reproductive age, characterized by hyperinsulinaemia and high levels of luteinizing hormone, with overlap with metabolic syndrome.
What are the main features of PCOS?
Features of PCOS include subfertility and infertility, menstrual disturbances like oligomenorrhoea and amenorrhoea, hirsutism, acne from hyperandrogenism, obesity, and acanthosis nigricans due to insulin resistance.
What are the key investigations for diagnosing PCOS?
Key investigations include pelvic ultrasound showing multiple ovarian cysts, hormone tests like FSH, LH, prolactin, TSH, testosterone, and SHBG. Glucose tolerance tests are also recommended.
What are the diagnostic criteria for PCOS according to the Rotterdam criteria?
The Rotterdam criteria for PCOS diagnosis require at least two of the following: infrequent or no ovulation, clinical/biochemical signs of hyperandrogenism, and polycystic ovaries on ultrasound.
How is hyperandrogenism identified in PCOS?
Hyperandrogenism in PCOS is identified through clinical signs such as hirsutism and acne or elevated levels of total or free testosterone.
summarise
Polycystic ovarian syndrome: features and investigation
Polycystic ovary syndrome (PCOS) is a complex condition of ovarian dysfunction thought to affect between 5-20% of women of reproductive age. The aetiology of PCOS is not fully understood. Both hyperinsulinaemia and high levels of luteinizing hormone are seen in PCOS and there appears to be some overlap with the metabolic syndrome.
Features
subfertility and infertility
menstrual disturbances: oligomenorrhoea and amenorrhoea
hirsutism, acne (due to hyperandrogenism)
obesity
acanthosis nigricans (due to insulin resistance)
Investigations
pelvic ultrasound: multiple cysts on the ovaries
NICE Clinical Knowledge Summaries recommend the following baseline investigatons: FSH, LH, prolactin, TSH, testosterone, sex hormone-binding globulin (SHBG) are useful investigations
raised LH:FSH ratio is a ‘classical’ feature but is no longer thought to be useful in diagnosis
prolactin may be normal or mildly elevated
testosterone may be normal or mildly elevated - however, if markedly raised consider other causes
SHBG is normal to low in women with PCOS
check for impaired glucose tolerance
Diagnostic criteria
a formal diagnosis should only be made after performing investigations to exclude other conditions
the Rotterdam criteria state that a diagnosis of PCOS can be made if 2 of the following 3 are present:
infrequent or no ovulation (usually manifested as infrequent or no menstruation)
clinical and/or biochemical signs of hyperandrogenism (such as hirsutism, acne, or elevated levels of total or free testosterone)
polycystic ovaries on ultrasound scan (defined as the presence of ≥ 12 follicles (measuring 2-9 mm in diameter) in one or both ovaries and/or increased ovarian volume > 10 cm³)
A 23-year-old woman presents to her general
practitioner with irregular periods. The patient describes oligomenorrhoea since menarche at age 12, with menstrual periods occurring approximately once every 8 weeks. The patient reports paying for laser treatment for excessive hair growth on her upper lip and chin.
On examination, the patient has cystic facial acne. Speculum and bimanual examinations are unremarkable.
The patient is referred for a transvaginal ultrasound and booked for a blood test.
What endocrine markers are most typical of the likely diagnosis?
Low LH:FSH ratio
Low serum cortisol concentration
Low sex hormone binding globulin concentration
Raised serum TSH concentration
Testosterone levels 10 times greater than the upper reference limit
Low sex hormone binding globulin concentration
Stereotypical PCOS results:
raised LH:FSH ratio
testosterone may be normal or mildly elevated
SHBG is normal to low
Low sex hormone binding globulin (SHBG) concentration is the correct answer. The patient’s clinical presentation is consistent with polycystic ovarian syndrome (PCOS). PCOS can be diagnosed if 2/3 criteria are met:
Features of hyperandrogenism (hirsutism, facial acne)
Polycystic ovaries on transvaginal ultrasound.
Biochemical features of hyperandrogenism.
SHBG is a plasma protein that binds the steroid hormones oestrogen, testosterone, and dihydrotestosterone. Low concentrations of SHBG increase the concentration of unbound, biologically active testosterone and dihydrotestosterone, leading to features of hyperandrogenism associated with PCOS.
Low LH:FSH ratio is incorrect, as a raised LH:FSH ratio is associated with PCOS. LH drives ovulation, while FSH drives follicle maturation; anovulatory cycles and oligomenorrhoea are hallmarks of PCOS, resulting in proportionally increased release of LH, rather than FSH, from the anterior pituitary.
Low serum cortisol concentration is incorrect. Low serum cortisol concentrations may be associated with adrenal insufficiency, rather than polycystic ovarian syndrome.
Raised serum TSH concentration is incorrect. Thyroid dysfunction is not classically associated with PCOS.
Testosterone levels 10 times greater than the upper limit is incorrect. Although hyperandrogenism is a hallmark of PCOS, this is typically mild. A testosterone concentration 10 times greater than the upper reference limit should raise concern for a more sinister cause of hyperandrogenism, such as an androgen-secreting tumour (Leydig cell tumour).
buzz words
irregular periods - oligomenorrhoea
excessive hair growth on upper lip and chin.
cystic facial acne
