July 31, 2010

Q&A: Post-Menopausal Osteoporosis and Vertebral Fractures

Natural menopause is defined as the permanent cessation of menstrual periods, determined retrospectively after a woman has experienced 12 months of amenorrhea without any other obvious pathological or physiological cause.

In this article:
Postmenopausal bone loss
MCQ exam: clinical scenario
MCQ exam: answer
MCQ exam: explanation

Postmenopausal bone loss

Natural menopause occurs at a median age of 51.4 years in normal women and is a reflection of complete, or near complete, ovarian follicular depletion, with resulting hypoestrogenemia and high follicle-stimulating hormone (FSH) concentrations.

Ovarian estradiol production and secretion decreases and stops altogether after menopause as a result of ovarian follicular depletion. However, the ovary continues to secrete testosterone. There are a number of long-term effects of estrogen deficiency, including osteoporosis, cardiovascular disease, and dementia.

Bone loss begins during the menopausal transition. The annual rates of bone mineral density loss appear to be highest during the one year before the final menstrual period through two years after.

MCQ exam: clinical scenario

A 55 year old woman who has just gone through her menopause is concerned that she may develop vertebral fractures. She has never had any surgery before and has no relevant medical history.

What is the most effective way of preventing pathological fractures post-menopause?

a) Clonidine J Vaginal lubricant
b) Combined Oestrogen and progestogen replacement therapy
c) Oestrogen only HRT
d) Progestins
e) Mineral supplements

MCQ questions & answers on medicalnotes.info

MCQ exam: answer

The correct answer is B.
Combined Oestrogen and progestogen replacement therapy is the most effective way.

MCQ exam: explanation

Because established osteoporosis may not be significantly reversed, medical management should emphasize prophylaxis rather than treatment. Patients should be advised to stop smoking, reduce the intake of dietary phosphates, and exercise regularly to preserve bone mass.

Oestrogens have been shown to prevent the loss of bone mass and to reduce the incidence of osteoporotic fractures. They act by decreasing bone resorption, by increasing intestinal calcium absorption, and by reducing renal calcium excretion.

The inclusion of progesterone or a progestogen in hormone replacement therapy (HRT) inhibits endometrial proliferation and minimizes the risk of endometrial hyperplasia and subsequently endometrial carcinoma caused by unopposed exogenous oestrogens. Progestogens are therefore an essential part of HRT for women with an intact uterus. There are substantial differences between the currently available progestogens both in chemical structure and in pharmacological profile. It is important to consider these differences when HRT is prescribed.

Low doses of oestrogen appear to be as effective as higher doses; 0.625 mg and 1.25 mg of conjugated equine estrogen (CEE) are equally effective in preventing bone loss and in reducing the incidence of fractures. Because bone loss is irreversible, estrogen treatment initiated shortly after menopause will maximize the amount of bone preserved. Treatment should be taken for at least 6 years to reduce substantially the lifetime risk for fracture.

No method identifies all patients in whom osteoporosis will develop; hence, most postmenopausal women are potential candidates for this therapy. A measurement of baseline bone density may help patients for whom the decision to initiate estrogen replacement is difficult. However, normal bone density does not rule out the future development of osteoporosis.

Reference(s)
1). UpToDate: Clinical manifestations and diagnosis of menopause. Available online: https://www.uptodate.com/contents/clinical-manifestations-and-diagnosis-of-menopause

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