Polycystic ovary syndrome (PCOS) Flashcards
Define polycystic ovary syndrome (PCOS).
A heterogeneous endocrine disorder that appears to emerge at puberty.
Includes:
- symptoms of hyper-androgenism,
- presence of hyper-androgenaemia,
- oligo-/anovulation,
- and polycystic ovarian morphology on ultrasound
What are the clinical features of PCOS?
Clinical features vary widely
What is the aetiology of PCOS?
Unknown
Insulin resistance and consequent compensatory hyperinsulinaemia are key factors. Hyperinsulinaemia then causes:
- Reduced SHBG -so more testosterone in biologically active unbound form is available
- Increased androgen producttion which stops follicular development and causes anovulation amd menstrual disturbance
- Weight gain due to insulin resistance
Hormonal imbalance is common
- LH elevated due to increased amplitute and frequency of LH pulses
- Theca cells of ovary produce excess androgens due to hyperinsulinaemia/high LH. Theca cells in PCOS are more efficient at converting androgens to testosterone
- Serum oestrogen levels raised as follicular development stops at a stage short of full maturity of the ovulatory follicle so there is no oestrogen deficiency and no progestogen so endometrium becomes hyperplastic. Excess oestrogen may also be converted to testosterone in peripheral fat.
Genetic link in some cases but no specific genes identified
What are some risk factors for PCOS?
- FH of PCOS
- Premature adrenarche
- Obesity - having PCOS does not appear to increase risk of obesity
How common is PCOS?
1 in 10 - many undiagnosed
Single most common cause of infertility in young women
Most common endocrinopathy in women of reproductive age
What are the clinical features of PCOS?
- subfertility and infertility
- menstrual disturbances: oligomenorrhea and amenorrhoea
- hirsutism, acne (due to hyperandrogenism)
- obesity
- acanthosis nigricans (due to insulin resistance)
What investigations should be done for PCOS?
Bloods:
- Calculate free androgen index - normal or elevated
- FSH, LH - measure to rule out premature ovarian insufficiency etc.
- TSH - exclude hypothyroidism
- Prolactin - exclude hyperprolactinaemia
Imaging:
- US - multiple cysts on ovaries. Ultrasound scan should not be used for the diagnosis of PCOS in adolescents due to the high incidence of multi-follicular ovaries in this life stage.
What does the free androgen index show? What is it in PCOS?
Used to caculate physiologically active testosterone level
100 x total testosterone / SHBG level
Normal or elevated in PCOS
Normal is <5
If testosterone is twice upper limit of normal/>5nmol/L, should you suspect PCOS?
No suspect other causes e.g. andorgen-secreting tumour or CAH
What is the conservative management (advice and screening) of PCOS?
Inform of possible long-term complications
Advise on measures to reduce CVD risk, including diet, exercise, and where appropriate, weight loss and smoking cessation.
Offer screening for IGT/T2DM (2 hour post 75g OGTT), CVD risk factors (QRISK2 assessment tool).
Check BP for HTN
Regular monitoring
What are the benefits of weight loss in PCOS?
Explain that weight loss may:
- Reduce hyperinsulinism and hyperandrogenism.
- Reduce the risk of type 2 diabetes and CVD.
- Result in menstrual regularity.
- Improve the chance of pregnancy (if it is desired).
What is the management of oligomenorrhoea/amenorrhoea in PCOS?
- Cyclical progestogen e.g. medroxyprogesterone 10 mg daily for 14 days every 1–3 months. This helps prevent endometrial hyperplasia.
- Low-dose COC
- LNG-IUS
What is the management of acne in PCOS?
COC - 1st line
+/- topical retinoids, topical/oral antibiotics
What is the management of hirsutism in PCOS?
- Lifestyle changes - weight loss may reduce hyperandrogenism; shaving and waxing
- Topical eflornithine cream - ameliorates hirsutism
- COC - but more effective for acne than hisrsutism; modestly inhibits gonadotrophin secretion + increases SHBG to decrease testosterone
- Anti-androgens e.g. spironolactone, flutamide, cyproterone, finasteride. Used for severe hisrsutism.
- GnRH analogues e.g. leuprorelin in very severe ovarian hyper-androgenism
What is the management of infertility in PCOS?
- Lifestyle changes - weight loss if overweight will improve chances of pregnancy, avoid smoking.
- Metformin - if weight loss is unsuccessful; may restore menses/ovulation to the point that conception is possible
- Letrozole or clomifene - induce ovulation/anti-oestrogen; letrozole for all women or clomifene if BMI>30kg/m2. Letrozole is an aromatase inhibitor (prevents conversion of androgens to oestrogens).
- Consider referral for fertility treatment e.g. IVF
What are the four anatomical subtypes of osteomyelitis?
- I - medullary and endosteal bone (haem)
- II - suuperficial osteomyelitis (contiguous)
- III - medullary and cortical involvement, but only part of circumference of bone affected
- IV - diffuse involvement of entire circumference of bone
What investigations would you do for osteomyelitis?
Bloods:
- FBC - raised WCC/normal in chronic
- ESR/CRP - raised/normal in chronic. Good indicator of treatment efficacy.
- Culture of aspirate/biopsy/blood - deep samples should be taken after stopping antibiotics for 2 weeks.
- Histology - gram stainng of aspirate gives good indication of organism present
Imaging:
- Plain radiographs - look for fractures, tumours, osteopenia (6-7 days after infection onset). In chronic infection “fallen leaf” sign is when piece of endosteal sequestrum detaches and falls into medullary canal.
- US - associated collections, subperiosteal abscesses, joint effusions (=septic arthritis), guiding biopsy
- MRI /CT - most hepful T2.
What may be seen in acute and chronic osteomyelitis on plain radiograph imaging?
acute disease:
- osteopenia appears 6-7 days after infection onset,
- and evidence of bone destruction,
- cortical breaches,
- and periosteal reaction follow quickly;
- involucrum and sequestra* can sometimes be seen, with further diffuse osteopenia developing later secondary to disuse of the affected limb;
chronic disease:
- intramedullary scalloping, cavities, and cloacae may be seen,
- with a ‘fallen leaf’ sign noted when a piece of endosteal sequestrum has detached and fallen into the medullary canal
