Hot flashes are sudden-onset, spontaneous and episodic sensations of warmth, usually felt on the chest, neck, and face immediately followed by an outbreak of sweating. They are the most common reason that women seek medical care during the peri-menopausal period especially if the symptoms impair quality of life. The onset of hot flashes can be associated with perspiration, heart palpitations, headache, weakness, fatigue, faintness and anxiety, and they can be triggered by warm environments, hot drinks or emotional stress. Hot flashes are variable in terms of duration, severity, and frequency. Frequency and severity can increase during the transition to menopause and peak at approximately one year after the final menstrual period. They can persist for 6 months to several years usually decreasing in frequency and intensity over time after the final menstrual period. On average, they last less than five minutes. The average frequency varies from 10 times per day to several times per week. The mean duration is 1.2 years.
The exact pathogenesis of hot flashes is unknown, but studies indicate that VMS (vasomotor symptoms) results from a defect in central thermoregulatory function. The physiological changes accompanying VMS are clear and well documented, yet several hypotheses about the mechanism of action exist. Various hormones and neurotransmitters modulate vasomotor symptoms, most importantly estrogen. The thinking is that ovarian estrogen withdrawal is the initial mechanism leading to hot flashes. Norepinephrine and serotonin also have a role in the defect in thermoregulation with VMS which is why SSRIs and SNRIs have been used to treat VMS. Research documents that plasma levels of norepinephrine metabolites rise before and during a hot flash. Peripheral vasodilation occurs, increasing up to 10 to 15 degrees C in the fingers and toes.A rise in systolic blood pressure and heart rate also occurs.
Screening for hot flashes should take place in all perimenopausal women. Hot flashes should also receive treatment if they impair a woman's quality of life, in particular, daytime activities and sleep. At the same time, many women have hot flashes and do not need treatment. In the most severe cases, a woman can awake several times during the night which in the long term can cause cognitive and anxiety disorders.
Several treatment options exist with only a few being FDA approved. When selecting a treatment option, the healthcare provider should encourage the safest option first, such as lifestyle changes, and then proceed to the following hormonal and/or non-hormonal treatments. The most effective treatment for hot flashes is systemic estrogen with a 75% reduction of VMS frequency. Progestin therapy at high doses, including DMPA and megestrol, also decrease hot flashes but are not nearly as effective as estrogen. Progesterone treatment should be a consideration in women who cannot take estrogen therapy. Hormone therapy (HT) administration can be in various forms including oral, parenteral, topical, transbuccal, vaginal or transdermal, with each route having various formulations and doses of estrogen and/or progesterone. The consensus is that HT for treatment of hot flashes or vasomotor symptoms should be prescribed at the lowest effective dose for the shortest amount of time needed for management of the symptoms. The safety of HT is controversial.
The Women's Health Initiative (WHI) is the largest study of its kind that evaluated the risks of hormone therapy in menopausal women. It was a multicenter, double-blind, placebo-controlled trial of women age 50 to 79 years at baseline, designed to assess HT’s impact on cardiovascular disease. Initial findings of the WHI reported that combined HT was not cardioprotective. The WHI also found that HT actually increased the incidence of breast cancer, thromboembolic events, and stroke. It is now generally contraindicated in women with a history of breast cancer. As a result of the WHI findings, the current recommendation for the use of HT is to treat moderate to severe vasomotor symptoms at the lowest possible dose. An alternative to the conventional HT are compounded bioidentical hormones, but currently, there is no evidence that these compounded products are as safe, effective or superior to conventional HT for the treatment of vasomotor symptoms. Bioidentical hormone products that are currently FDA approved include 17B-estradiol (transdermal or oral) and micronized progesterone (oral or vaginal). Non-FDA approved bioidentical HT include compounded preparations.
Since 2002, after the initial findings of the WHI were published, the use of HT decreased substantially (as much as 80%) as patients and providers turned to alternate forms of managing VMS. Non-prescribed, nonhormonal therapies studied include soy extract, red clover isoflavones, black cohosh, and Chinese herbs. Their safety and efficacy remain unclear. Although better quality studies are needed, some studies have found these nonhormonal options to be less effective than placebos.
Prescription nonhormonal therapies include:
These medications are more effective than placebos but not as effective as hormonal therapy. Paroxetine was the first nonhormonal prescription medication that was FDA approved for use in the treatment of menopausal vasomotor symptoms including hot flashes. The typically prescribed dose is an ultra-low 7.5mg daily. It moderately reduces hot flashes versus the placebo. Paroxetine and other SSRIs are not recommended for women with tamoxifen-induced hot flashes due to their effects as a strong inhibitor of the drug-metabolizing enzyme CYP2D6 and therefore interfering with tamoxifen's therapeutic benefit. SNRIs such as venlafaxine, although not FDA approved for treatment of hot flashes, are recommended for management of hot flashes in a woman taking tamoxifen. Other options for women with a history of breast cancer include gabapentin and clonidine.
Lifestyle changes such as exercise, layering clothes, maintaining lower room temperature, drinking cool drinks, and avoiding caffeine and alcohol are reasonable to consider for the management of VMS even if there aren't conclusive studies proving their efficacy. Unfortunately, only limited studies exist for nonmedicated and integrative medical treatments of hot flashes, but research is growing in the integrative medicine field. Integrative medical treatments including breathing exercises, relaxation techniques, changes in diet, yoga, acupuncture, reflexology, and hypnosis could provide some relief in the treatment of vasomotor symptoms.
Hot flashes are most commonly associated with perimenopause and menopause. In any woman presenting with hot flashes, whether she is of perimenopausal age or status-post surgical or medically induced menopause, pathology must be ruled out as the cause. Menopause can be confirmed by the cessation of menses for at least 12 months and with estradiol and FSH levels.
The differential diagnosis for hot flashes includes:
Hot flashes can also be caused by medications including:
Hot flashes are a common (up to 80%) side effect in women taking tamoxifen.
Prognosis of hot flashes is good. Most women's hot flashes will resolve after 5 years. Only about 10% of women will have symptoms past 10 years.
A patient's first source of information should be their primary care provider, or obstetrician and gynecologists. Patients can access patient education material online at the American College of Obstetricians, American Society of Reproductive Specialists and the North American Menopause Society.
Shared decision-making and communication between the gynecologist, nurse practitioner, primary care provider, nursing staff, pharmacy, and patient are critical in managing hot flashes. The patient should be well educated on her diagnosis, what to expect during the perimenopausal period and her options for treatment including the risks, benefits, alternatives of each therapy. They should receive counsel that HT is proved to be safe and effective in the treatment of VMS. They should receive education about the FDA approval status of the different forms of therapies. All these approaches are best handled by an interprofessional team incorporating the personnel outlined above, to deliver optimal patient care during menopause. [Level V]
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