Thursday, July 29, 2010

An article in the July 29 issue of the New England Journal of Medicine reviewed evidence for the use of acupuncture for chronic low back pain.
"Acupuncture is a therapeutic intervention characterized by the insertion of fine, solid metallic needles into or through the skin at specific sites," write Brian M. Berman, MD, from the University of Maryland School of Medicine in Baltimore. "The technique is believed to have originated in China, where it has remained a fundamental component of a system of [medicine that] espouses an ancient physiological system (not based on Western scientific empiricism) in which health is seen as the result of harmony among bodily functions and between body and nature. Internal disharmony is believed to cause blockage of the body's vital energy, known as qi, which flows along 12 primary and 8 secondary meridians."

Tenderness on palpation is thought to be evidence of blockage of qi, and inserting acupuncture needles at specific points along the meridians is believed to restore the proper flow of qi. The analgesic effects of acupuncture appear to be based on neural innervation, because they are completely blocked by local anesthesia at needle-insertion sites. Furthermore, acupuncture stimulates the release of endogenous opioids in brainstem, subcortical, and limbic structures, as well as producing mechanical stimulation of connective tissue and other effects on local tissues. Despite these effects, the mechanisms underlying chronic pain relief by acupuncture are not completely understood.

Acupuncture is seldom regarded as the first choice of treatment, in part because randomized controlled clinical trials and large meta-analyses have not proven it to be more effective than sham acupuncture in relieving low back pain. However, it may be useful as part of a multidisciplinary approach to the management of chronic low back pain, along with physical therapy, pain medication, and/or exercise.
"Acupuncture is a regulated discipline, and patients should be referred only to practitioners who are licensed by the state in which they practice," the review authors write. "A diploma from the National Certification Commission for Acupuncture and Oriental Medicine is a requirement for licensure in most states. Physicians may practice acupuncture in the United States after completing one of several medical acupuncture programs."

Contraindications to acupuncture include coagulation and bleeding disorders, use of anticoagulants, severe psychiatric disease, and local skin infections or trauma. Electroacupuncture should not be used at the site of pacemakers or other implanted electrical devices. Pregnant women may undergo acupuncture, but not at specific acupuncture points known to be especially sensitive to needle insertion or at acupuncture points in the abdominal regions.

One treatment is considered to be insufficient, and recent trials of acupuncture for low back pain used at least 12 acupuncture sessions, often starting with 2 sessions a week and tapering off after 4 weeks to once weekly, with booster treatments sometimes used monthly or every other month. Acupuncture should be discontinued if there are no apparent effects after 10 to 12 sessions.
"There is continuing debate in the medical community regarding the role of the placebo effect in acupuncture," the review authors write. "The most recent well-powered clinical trials of acupuncture for chronic low back pain showed that sham acupuncture was as effective as real acupuncture. The simplest explanation of such findings is that the specific therapeutic effects of acupuncture, if present, are small, whereas its clinically relevant benefits are mostly attributable to contextual and psychosocial factors, such as patients' beliefs and expectations, attention from the acupuncturist, and highly focused, spatially directed attention on the part of the patient."

Joint clinical practice guidelines from the American College of Physicians and the American Pain Society recommend that clinicians consider acupuncture as one possible treatment option for patients with chronic low back pain refractory to self-care (level of supporting evidence, fair). According to the North American Spine Society, acupuncture offers better short-term pain relief and functional improvement than no treatment, and adding acupuncture to other treatments is more effective than other treatments alone, but high-quality, randomized controlled trials are still needed comparing acupuncture with no treatment and with sham acupuncture.

Sunday, July 25, 2010

A report in the Archives of Neurology suggests that Vitamin E may play a modest role in altering the course of dementia. Compared with participants with the lowest intake, investigators found that those patients with higher vitamin E intake were 25% less likely to develop dementia.

"When beta-amyloid — a hallmark of pathologic Alzheimer disease — accumulates in the brain, an inflammatory response is likely evoked that produces nitric oxide radicals and downstream neurodegenerative effects," report investigators led by Elizabeth Devore, ScD, from the Erasmus Medical Center in Rotterdam, the Netherlands. "Vitamin E is a powerful fat-soluble antioxidant that may help to inhibit the pathogenesis of dementia."

Vitamin E is found in whole-grain foods, eggs, milk, nuts, seeds, avocado, spinach, and unheated vegetable oils. The Rotterdam Study previously found that higher dietary intakes of vitamins E and C were associated with a lower risk for dementia and Alzheimer's disease.

In this new long-term follow-up of the Rotterdam Study, investigators followed participants for 9.6 years. The population-based prospective cohort study included 5395 people free of disease at baseline.
A total of 465 people developed dementia. Of these, 365 were diagnosed with Alzheimer's disease. The investigators found that higher dietary intake of vitamin E, but not vitamin C, beta carotene, or flavonoids, was associated with lower long-term risk for dementia.

These results conflict with previous findings, which suggested a link between vitamin C intake and dementia risk. Probably the bottom line is to eat a healthy diet.

Tuesday, July 20, 2010

The most common sleep complaint in adults is insomnia and is a significant health concern. The criteria for a diagnosis of primary insomnia include difficulty with falling asleep, difficulty remaining asleep, waking up too early, or failing to achieve restorative sleep for a period of 1 month or more while experiencing significant distress and/or impairment in daily functions. One poll found that 64% of participants reported a sleep problem at least a few nights each week, with 41% reporting problems almost every night. Insomnia is 41% more common in women than in men.

Although there are several different degrees of insomnia, three types of insomnia have been clearly identified: transient, acute, and chronic. Transient insomnia lasts for less than a week. It can be caused by another disorder, by changes in the sleep environment, by the timing of sleep, severe depression, or by stress. Its consequences - sleepiness and impaired psychomotor performance - are similar to those of sleep deprivation. Acute insomnia is the inability to consistently sleep well for a period of less than a month. Chronic insomnia lasts for longer than a month. It can be caused by another disorder, or it can be a primary disorder. Its effects can vary according to its causes. They might include being unable to sleep, muscular fatigue, hallucinations, and/or mental fatigue; but people with chronic insomnia often show increased alertness.

Patterns of insomnia are:
Onset insomnia - difficulty falling asleep at the beginning of the night, often associated with anxiety disorders.
Middle-of-the-Night Insomnia - Insomnia characterized by difficulty returning to sleep after awakening in the middle of the night or waking too early in the morning
Terminal (or late) insomnia - early morning waking. Often a characteristic of clinical depression.

Poor sleep quality can occur as a result of sleep apnea or major depression. Poor sleep quality is caused by the individual not reaching stage 3 or delta sleep which has restorative properties.

A common misperception is that the amount of sleep required decreases as a person ages. The ability to sleep for long periods, rather than the need for sleep, appears to be lost as people get older. Some elderly insomniacs toss and turn in bed and occasionally fall off the bed at night, diminishing the amount of sleep they receive.

Treatment for insomnia varies depending on the cause. This is why a good workup by a sleep specialist is the best way to make a proper diagnosis and lay out a treatment plan.

Saturday, July 17, 2010

The July issue of the Archives of Neurology reported a longitudinal study of more than 3,000 subjects in which a link between vitamin D and Parkinson’s disease was found. In the 29-year follow-up period, there were 50 incident cases of Parkinson's disease. The study was carried out in Finland where there is restricted sunlight exposure. It is a population that typically has low vitamin D levels. The mean serum level was about 50% of the suggested optimal level of 75 to 80 nmol/L.
The investigators found that individuals with a serum vitamin D concentration of at least 50 nmol/L had a 65% lower risk for Parkinson's than those with values less than 25 nmol/L after adjustment for several potential confounders. The relative risk between the highest and lowest vitamin D levels was 0.35.

Vitamin D is no longer considered a vitamin, but rather a hormone that has autocrine and paracrine functions well beyond those of regulating calcium absorption and bone health.

The exact mechanisms by which vitamin D may protect against Parkinson's disease are not fully understood. Vitamin D has, however, been shown to exhibit neuroprotective effects through antioxidative mechanisms, neuronal calcium regulation, immunomodulation, enhanced nerve conduction, and detoxification mechanisms.

The association with and possible causal role of insufficient vitamin D in many chronic diseases, such as Multiple Sclerosis, is becoming more widely appreciated yet what constitutes an optimal blood concentration of vitamin D for humans, and specifically for the human nervous system, remains unknown.

Friday, July 16, 2010

Making the news this last week was a gene for Alzheimer’s Disease (AD). This prompted a friend to ask me, “Why would you want to know if you were going to develop the disease?” Good question. One reason is for genetic planning. Another reason is that early diagnosis may lead to earlier treatment, and thus better prognosis. After all, this approach has been successful in preventing diseases such as cervical cancer and heart attacks.

But early treatment requires early diagnosis and not all people with dementia have AD. To this end solid criteria must be developed to identify a “preclinical state.” Put another way, we need to be able to identify AD far in advance of symptoms. Genetic testing will be helpful but in itself is not sufficient.

Okay, so what test might yield such information? Probably it will come from imaging studies (MRI or PET scans) that measure the metabolism and accumulation of amyloid, an insoluble protein. Amyloid accumulates in neurons of AD patients, causing cell death. Microscopically AD patients’ brains show “tombstones,” which are small deposits of amyloid that remain after neurons die. So amyloid accumulation is likely to become one metric for defining preclinical AD, allowing people with positive family histories of the disease to be successfully diagnosed and treated.

Tuesday, July 13, 2010

The Framingham study is a large prospective study of over 5,000 men and women living in Framingham, Massachusetts who have been followed every 2 years since 1948. Data from it is used to estimate risk of heart and other diseases. The dementia part of the study began in 1975 using several neuropsychological tests. Recent data from the study reports that people who participate in moderate to heavy physical activity have a 45% lower risk for dementia over time.

"A reduced risk of dementia may be one of the additional health benefits that can actually be derived from maintaining at least moderate physical activity," lead author Zaldy Tan, MD, MPH, from the Brigham and Women's Hospital, VA Boston, and Harvard Medical School, in Massachusetts, concluded. Dr. Tan presented the results at the Alzheimer's Association International Conference on Alzheimer's Disease 2010.

Previous findings from the Framingham have already shown moderate or high physical activity to be associated with a number of positive outcomes, including a reduced risk for stroke and cardiovascular disease, higher high-density lipoprotein cholesterol levels, a reduced risk for colon cancer, and lower overall rates of mortality.

Physical activity is a potential preventive factor that would likely take years to manifest its effect, "so the fact that we've followed them for over 20 years, this is something that suggests that long-term physical activity actually works," Dr. Tan noted. The mechanism is not clear, he added, but reduction of cardiovascular risk factors such as hypertension, or the release of neurotrophic factors, are possible effects.

The Framingham study is not the only one to demonstrate this relationship. A recent review showed that 20 of 24 population-based studies showed a link between physical activity and reduced risk for dementia or cognitive decline. The flip side of this is that four of those studies did not support the correlation. However, the Framingham study is one of the best because it has such well designed, long-term follow-up.

Saturday, July 10, 2010

As a back pain sufferer, I was interested to read in the July 7th issue of the Journal of the American Medical Association (JAMA) that glucosamine is not significantly different from placebo for reducing pain-related disability or improving health-related quality of life in patients with chronic low back pain. Years ago I’d tried the dietary supplement without success even though a lot of people swear by it.

Because glucosamine is a precursor molecule involved in building tendons, ligaments, and cartilage it’s widely believed that it helps restore cartilage as well as having anti-inflammatory properties. Despite conflicting data on its efficacy it has been widely used as a treatment for osteoarthritis. Some estimates suggest that more than more than 25% of patients with chronic LBP have tried glucosamine in various forms.

The research was a well-designed clinical study conducted at the Oslo University Hospital Outpatient Clinic using 250 patients with nonspecific chronic pain in the lower back. Patients were randomized to receive either a daily dose of 1500 mg of glucosamine sulfate or identical placebo administered as 3500-mg capsules. (The study design was double-blind cross over). The outcome was measured by a pain scale as well as one to assess quality of life.

Unfortunately low back pain is a significant cause of disability and medical cost in the United States. Too bad it doesn’t seem to have a significant therapeutic effect for relieving the symptoms.

Friday, July 9, 2010

A recently reported study of more than 3,000 people identified 9 modifiable risk factors for reducing more than 90% of all strokes. None of these will come as any big surprise. It’s been known for years that high blood pressure is associated with a higher incidence of brain hemorrhage (intracerebral hematoma) that results in either death of long-term injury. This relationship has been reaffirmed. This finding was based on the definition of hypertension as a systolic blood pressure greater than 150 mm Hg instead of the newer parameter of > 120 mm Hg.

A second, not surprising factor contributing to stroke, is smoking. For years it has been known that smoking increases the risk of both cardiac and stroke disease, mainly because it is associated with increased vascular problems. Diabetes is another factor that leads to vascular problem and stroke.

Two additional factors are obesity (as measured by abdominal girth) and regular exercise. These two have an obvious relationship with each other in that exercise helps maintain weight reduction in most people. Regardless of their interrelationship, they independently factored into the risk of stroke. Excessive alcohol consumption was also identified as a contributing factor.

So, your mother was right when she warned you to eat right, exercise, don’t smoke, and don’t drink excessively. The difference is that we probably didn’t believe our mothers. Now evidence based medicine shows she was correct.

Sunday, July 4, 2010

I went to the dentist the other week for a chipped tooth. He used a local anesthetic to numb the nerves to my maxilla, or upper jaw. So I thought I’d write a few words about local anesthetics. When injected near a nerve, these drugs cause reversible loss of function of that nerve. So, if the nerve carries fibers for sensation, blocking it results in anesthesia (lack of sensation).

Nerves transmit information by conducting action potentials, or brief impulses. They do this by allowing sodium and potassium to rapidly flow in and out of the fiber, a process called depolarization and repolarization. If you can chemically block this process, you can block the transmission of action potentials, thus rendering the nerve incapable of sending information. And this is exactly how local anesthetics, such as Novocain work.

All nerve fibers are sensitive to local anesthetics, but generally smaller diameter fiber are more sensitive than larger fibers. Local anesthetics block conduction in the following order: small myelinated axons (e.g. those carrying pain impulses), non-myelinated axons, then large myelinated axons. Because pain fibers are the smallest diameter fibers, a differential block can be achieved (i.e. block pain sensation more readily than other senses, such as light touch).

Permanent nerve damage can occur after a peripheral nerve block but is rare. Symptoms are very likely to resolve within a few weeks. The vast majority of those affected recover within four to six weeks. 99% of these people have recovered within a year. Very few nerve blocks result in some degree of permanent persistent nerve damage.

Nerve fibers are not the only tissues that use potassium and sodium conduction as the basis for their action. So do muscle fibers. For this reason, the amount of anesthetic injected must be carefully monitored. This is also the reason that some local anesthetics are effective in treating some severe types of cardiac arrhythmias.

True allergies to local anesthetics is very rare.