Wednesday, 27 May 2009
Nerve injection that can stop the nightmare of hot flushes
An injection in the neck might ease the symptoms of hot flushes. It blocks nerve signals involved in temperature regulation, and early results show that it can be highly successful.
In one study, the number of hot flushes women experienced in a week was cut by 90 per cent after a single injection. The women also had a similar reduction in night awakenings, a consequence of hot flushes.
Hot flushes are a common symptom of the menopause, affecting around 80 per cent of women.
They are a sudden sensation of intense heat or sweating in the upper body, which can start in the face, neck or chest before spreading upwards or downwards. They tend to last for five to ten minutes - and typically persist for two to three years.
Flushes occur when there is an increase in the amount of blood flowing to the skin. This causes a rise in skin temperature and leads to blood vessels just under the skin surface dilating, giving the characteristic florid cheeks associated with the menopause.
The exact cause of hot flushes is unknown. One theory is that the drop in levels of oestrogen that occurs around the menopause affects the hypothalamus, the part of the brain involved in the control of body temperature. Another theory is that changes in other brain chemicals, including serotonin, may be involved.
While for some women these symptoms are simply a nuisance, for others, the flushes and sweating can be very distressing, affecting many aspects of life, including work and sleep.
Some women find that hot flushes can be triggered by stress, alcohol, caffeine or spicy foods, so simply cutting back may help.
There is also a wide range of treatments available including HRT. This works by increasing levels of oestrogen, but it has been linked to side-effects such as bloating, weight gain, headaches and, more seriously, an increased risk of breast cancer.
Antidepressants, which increase levels of serotonin, are another treatment option, though again there is a risk of side-effects.
The new treatment is known as a stellate ganglion nerve block. The stellate ganglion is a collection of nerves on either side of the neck. It is part of the sympathetic nervous system which helps regulate heart rate, blood pressure and breathing rate. It also causes blood vessels to narrow, and is involved in sweating and temperature regulation.
'Some women find hot flushes can be triggered by stress, alcohol, caffeine or spicy foods, so simply cutting back may help'
It's thought that blocking the action of these nerves prevents the rise in skin temperature.
In a new trial at the Mayo Clinic in America, the treatment is being given to women who have had hot flushes for more than a month (with more than 28 a week) and found antidepressants and other treatments ineffective.
During the treatment, which takes around five minutes, a local anaesthetic is injected into the nerves with the help of X-ray guidance.
Patients are then being asked to keep a hot-flush and symptom diary for seven weeks. They will be followed up at two months, and thereafter monthly for a year.
Earlier smaller studies have already shown the injection to be highly effective. In one study at the University of Illinois, all 15 women who had the nerve block treatment had a minimum of an 80 per cent relief of symptoms, with few or no side-effects.
In a second study at the same centre, the frequency of hot flushes and sleep disturbance in women with breast cancer decreased by about 90 per cent after 12 weeks. How long the treatment is effective varied between patients: it is thought that some patients might need more injections to provide a longer-term effect.
'This is an interesting preliminary study,' says Sanjay Vyas, consultant gynaecologist at Southmead Hospital in Bristol. 'Hot flushes affect millions of women, and HRT, which is effective, does carry some risk. Anything that provides relief from hot flushes but does not carry risk would be welcome.
'I look forward to the results of larger studies, which should identify the risks and side-effects, as well as the benefits.'