MAYO CLINIC HEALTH LETTER Tools for Healthier Lives VOLUME 29 NUMBER 10 OCTOBER 2011
Inside this issue HEALTH TIPS . . . . . . . . . . . . . 3 Choosing omega-3s. NEWS AND OUR VIEWS . . . . 4 Alternative to the anti-clotting drug warfarin — is it for you? REGENERATIVE MEDICINE . . . . . . . . . . . . . . . 4 Stem cells for healing. RESILIENCE WITH AGE . . . . . 6 Bouncing back. GENETICS AND DRUGS . . . . . . 7 Tailoring drugs to you. SECOND OPINION . . . . . . . . 8
Coming in November NONCARDIAC CHEST PAIN Heartburn, not a heart attack. TREATING HIGH BLOOD PRESSURE Fine-tuning your goals. GRAVES’ DISEASE Thyroid in overdrive. PHARMACOGENOMICS Genetics intersecting with drug therapy.
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Peripheral neuropathy Potentially disabling nerve problems Lately, you’ve noticed an odd sensation in your toes — they feel prickly. Now and then they even feel as if they’re burning a bit. At first you wondered if your shoes might be the problem, but the burning sensation seems worse at night, and that’s hours after you’ve removed your shoes. If you have sensations such as these in your hands or feet, they may be the result of peripheral neuropathy, which is caused by nerve damage. That damage may be related to any number of causes, ranging from a traumatic injury to an underlying health condition, such as diabetes. Generally, early diagnosis and treatment offer the best chance of controlling symptoms and preventing more peripheral nerve damage.
Live wires disrupted
Your nervous system can be viewed in two broad categories. One is your central nervous system, which is your brain and spinal cord. The other is the peripheral nervous system, which includes the peripheral nerves. It’s these nerves that are affected by peripheral neuropathy, including: ■ Sensory nerves — These allow you to feel sensations such as heat,
Your nervous system is divided into two broad categories — the central nervous system and the peripheral nervous system. Your brain and your spinal cord (shown in yellow) make up your central nervous system. Peripheral nerves (shown in green) include the nerves that allow you to feel sensations, control your muscles and control involuntary body functions, such as heart rate and digestion. Most commonly, it’s the longest nerves — those that reach your toes or hands — that are first affected by peripheral neuropathy.
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pain or touch, and contribute to your sense of balance. ■ Motor nerves — These help control your muscle’s speed of contraction and their power. ■ Autonomic nerves — These control involuntary body functions, such as heart rate, blood pressure, digestion and bladder function. It’s most common for the longest nerves — those that reach to your toes — to be affected first. Depending on which of these nerves are affected, signs and symptoms vary. You may encounter: ■ Gradual numbness and tingling in your feet or hands that may progress up into your legs or into your arms ■ Burning pain ■ Pain that is sharp, jabbing or electric-like ■ Extreme sensitivity to touch, even light touch ■ Clumsiness or a lack of coordination Peripheral neuropathy affecting motor nerves can produce muscle weakness or even paralysis. Bowel or bladder problems are associated with damage to autonomic nerves. Numbness or reduced feeling associated with peripheral neuropathy may pose some dangers. For instance, if you touch a hot pan or plate, your normal response is to pull back quickly, avoiding a more severe burn. If parts of your body lack feeling, you’re less likely to protect yourself from injury. Another potential danger is for infection or inflammation to go undetected and untreated. Normally, inflammation causes increased pain — but that pain sensitivity may be reduced if you have peripheral neuropathy. This makes it important to regularly check affected areas for minor injuries and treat them to avoid infection. Being proactive is especially important if you have diabetes, which tends to slow wound healing.
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Peripheral neuropathy is a symptom, not a single disease. Determining its cause isn’t always easy. In many cases, a cause can’t be identified. Some peripheral neuropathies are due to genetic conditions. One of the most common acquired causes is diabetes, especially if your blood sugar level is poorly controlled. Many people who have diabetes eventually develop some type of neuropathy. Other conditions that can set off peripheral neuropathy include rheumatoid arthritis, lupus, kidney disease and an underactive thyroid (hypothyroidism). Certain viral or bacterial infections — including Lyme disease, shingles, hepatitis C, and HIV and AIDS — can cause or possibly make you more susceptible to peripheral neuropathy. Guillain-Barré syndrome affects peripheral nerves. Cancers, particularly blood-related cancers, may be a factor. Some tumors may develop in peripheral nerves. Nerves can also be injured as a result of growths in adjacent bones, tissue or ligaments. Vitamin deficiencies, especially a lack of certain B vitamins, can cause peripheral nerve dysfunction. Alcoholism has been associated with peripheral neuropathy. Poor dietary habits of alcoholics may lead to vitamin deficiencies. The potential for peripheral nerve damage is increased with exposure to toxic substances, such as heavy metals, and certain medications. The side effects of certain chemotherapy drugs used to treat cancer can be particularly concerning. For some, severed or damaged peripheral nerves may be caused by an accident or fall.
Sorting it out
The usual starting point in diagnosing the cause of peripheral neuropathy is a full medical and family history, as well as physical and neurological exams. From there,
October 2011
your doctor may request blood tests to check blood sugar and vitamin levels and to evaluate for the presence of abnormal proteins (monoclonal proteins), which can cause or be associated with peripheral neuropathy. Blood tests also show how well your kidneys, liver and thyroid are functioning. Other tests may include electromyography (EMG) — which measures electrical signals in peripheral nerves and the transfer of those signals to muscles — a nerve biopsy and possibly diagnostic imaging. Treatment is geared to managing the underlying condition causing the neuropathy. Doing so often improves the neuropathy on its own, or at least stops the damage from progressing. The other part of treatment is relieving painful symptoms. MAYO CLINIC HEALTH LETTER Managing Editor Aleta Capelle
Medical Editor Robert Sheeler, M.D.
Associate Editors Carol Gunderson Joey Keillor
Associate Medical Editor Amindra Arora, M.D.
Medical Illustration Michael King Customer Service Manager Ann Allen
Editorial Research Deirdre Herman Proofreading Miranda Attlesey Donna Hanson Julie Maas
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EDITORIAL BOARD Shreyasee Amin, M.D., Rheumatology; Amindra Arora, M.D., Gastroenterology and Hepatology; Brent Bauer, M.D., Internal Medicine; Julie Bjoraker, M.D., Internal Medicine; Lisa Buss Preszler, Pharm.D., Pharmacy; Bart Clarke, M.D., Endocrinology and Metabolism; William Cliby, M.D., Gynecologic Surgery; Clayton Cowl, M.D., Pulmonary and Critical Care; Mark Davis, M.D., Dermatology; Timothy Hobday, M.D., Oncology; Lois Krahn, M.D., Psychiatry; Suzanne Norby, M.D., Nephrology; Robert Sheeler, M.D., Family Medicine; Phillip Sheridan, D.D.S., Periodontics; Peter Southorn, M.D., Anesthesiology; Ronald Swee, M.D., Radiology; Farris Timimi, M.D., Cardiology; Matthew Tollefson, M.D., Urology; Debra Zillmer, M.D., Orthopedics; Aleta Capelle, Health Information. Ex officio: Carol Gunderson, Joey Keillor. Mayo Clinic Health Letter (ISSN 0741-6245) is published monthly by Mayo Foundation for Medical Education and Research, a subsidiary of Mayo Foundation, 200 First St. SW, Rochester, MN 55905. Subscription price is $29.55 a year, which includes a cumulative index published in December. Periodicals postage paid at Rochester, Minn., and at additional mailing offices. POSTMASTER: Send address changes to Mayo Clinic Health Letter, Subscription Services, P.O. Box 9302, Big Sandy, TX 75755-9302.
Electromyography with nerve conduction velocity If you have signs or symptoms that indicate a nerve disorder such as peripheral neuropathy, an electromyography (EMG) may be done. EMG is a diagnostic procedure that measures electrical signals in peripheral nerves and the transfer of those signals to muscles. A nerve conduction velocity (NCV) study, part of an EMG, uses surface electrodes — electrodes taped to the skin — to measure the speed and strength of signals traveling between two or more points. A neurologist or a technician places surface electrodes at various locations on your skin depending on where you’re experiencing problems. The electrodes will at times transmit a tiny electrical current that you may feel as a twinge or spasm. Your doctor might recommend several treatment options, such as: ■ Pain relievers — Nonprescription pain relievers may help relieve mild symptoms. Prescription pain relievers may be helpful for more-severe symptoms. ■ Anti-seizure drugs — Medications such as gabapentin (Neurontin), topiramate (Topamax), pregabalin (Lyrica), carbamazepine (Tegretol) and phenytoin (Dilantin), which were first developed to treat epilepsy, are often used to treat nerve pain. ■ Lidocaine patches and topical gels or creams — Lidocaine products or products containing lidocaine and other topicals may be applied where hypersensitivity to light touch is most problematic. ■ Certain antidepressants — Tricyclic antidepressants — such as amitriptyline and desipramine (Norpramin) — and serotonin and norepinephrine reuptake inhibitors (SNRIs) — such as duloxetine (Cymbalta) and venlafaxine (Effexor) — can relieve pain by altering the chemical processes in your brain and spinal cord that cause you to feel pain. ■ Transcutaneous electrical nerve stimulation (TENS) — Gentle electric current delivered through adhesive electrodes on the skin may improve symptoms. TENS is applied several times a day.
Various alternative treatments may help relieve symptoms of peripheral neuropathy. These include: ■ Acupuncture — This may help reduce symptoms, although multiple sessions may be needed before improvement is noticed. ■ Biofeedback — This allows you to practice techniques such as relaxation and guided imagery while monitoring your response. Doing so can help you deal with the stress of chronic pain.
Getting ahead of the problem
When nerves are damaged, you may encounter unusual or even unpleasant sensations in the area supplied by those nerves. Early treatment of peripheral neuropathy offers the best chance of preventing further damage and successfully treating symptoms. Diabetes is thought to be the leading cause of peripheral neuropathy. A fasting blood sugar screening test can detect prediabetes. On the plus side, there’s strong evidence that lifestyle interventions can significantly reduce the likelihood of type 2 diabetes developing in people at risk of the condition. Those interventions include a dedicated effort to eat a healthy diet — one that emphasizes fruits, vegetables and whole grains — regular exercise and losing excess weight. ❒ October 2011
Health tips Choosing omega-3s The American Heart Association recommends eating two 3.5-ounce servings each week of cold-water fish, such as herring, mackerel, salmon, sardines or tuna. However, that much fish could significantly increase your exposure to toxins. If fish isn’t your wish, a daily dose of 250 to 500 milligrams (mg) of the combined omega-3 fatty acid types called DHA and EPA is a good target. A daily dose of 1,000 mg is often recommended if you’ve had a heart attack or have cardiovascular disease. Compare these options: ■ Fish oil supplements — These often contain a ratio of no less than 2 parts DHA to 1 part EPA, or vice versa. A low-cost supplement with combined DHA and EPA of 500 mg is about 10 cents a pill. Reviews of fish oil have failed to detect toxins. ■ Krill oil supplements — These are often two to four times more expensive than are standard fish oil pills. One study found that taking about one-third less krill oil than standard fish oil resulted in similar blood levels of DHA and EPA. ■ Algae-derived supplements — These are reasonably priced, but provide only DHA. ■ Flaxseed or walnut oils — These contain the plant version of omega-3 called ALA, which is probably best in a supporting role to other sources of omega-3s. ❒ www.HealthLetter.MayoClinic.com
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News and our views Alternative to the anti-clotting drug warfarin — is it for you? For decades, the anti-clotting drug warfarin (Coumadin) has been an effective, go-to drug for preventing the formation of blood clots within the body. For older adults with atrial fibrillation, it helps prevent strokes by inhibiting the development of blood clots in the heart, which can travel to — and even block — an artery supplying blood to the brain. However, a new drug — called dabigatran (Pradaxa) — is challenging warfarin’s dominance. Dabigatran appears to be more effective at preventing strokes — at least in people who don’t also have a faulty or mechanical heart valve. As for serious side effects, dabigatran causes only one-third the risk of bleeding inside the brain (hemorrhagic stroke) as does warfarin. However, dabigatran use leads to a significantly higher rate of major gastrointestinal bleeding than does warfarin. Routine blood testing to closely monitor and adjust (calibrate) the medication dose is needed with warfarin, but not dabigatran. And, with dabigatran, you don’t need to restrict your intake of vitamin K — such as by avoiding green leafy vegetables — as you do when taking warfarin. Mayo Clinic experts recognize the increased convenience of taking dabigatran, though it must be taken twice a day, rather than once a day as is warfarin. Still, they typically recommend the drug over warfarin only for people in whom regular blood testing is challenging or proper calibration of warfarin dosage is difficult. When warfarin therapy is managed well, Mayo experts say that it can provide equivalent stroke-prevention benefit to that of dabigatran. They also note several drawbacks of dabigatran. Compared with warfarin, dabigatran is more likely to cause stomach upset. Unlike warfarin, there’s no antidote for dabigatran, so severe bleeding may be more difficult to treat. Those taking dabigatran have a slight but significant increase in heart attack risk. In addition, studies suggest that a lower dose of oral dabigatran — 110 milligram twice daily — may be safer for those older than 75, but that particular preparation isn’t available in the United States. Also keep in mind that dabigatran is a brand-name drug that costs more than does warfarin. However, the extra expense may be partially or fully negated by eliminating the need for routine testing that is required with warfarin. Talk to your doctor to learn whether your personal health needs make changing your anticoagulation medication to dabigatran a good choice for you. It’s important to let all your health care providers — including your dentist — know if you’re taking this blood thinner. Dabigatran causes an increased risk of bleeding and it’s difficult to determine the extent of its blood-thinning effect if a procedure is urgently needed. ❒
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Regenerative medicine Stem cells for healing Imagine physicians treating a damaged heart by injecting cells that could create healthy new heart muscle and blood vessels. Or treating diseases — perhaps Parkinson’s, diabetes or Alzheimer’s — by implanting cells that could replace damaged or destroyed cells caused by the disease. Wishful thinking? Maybe not, thanks to the emerging field of regenerative medicine, which seeks to regenerate healthy organs, tissues and cells in areas where they’re damaged. The tools used to reach this goal are based on various types of stem cells, which can produce some or all types of cells. With the exception of bone marrow transplantation and a few other applications, use of stem cells in medicine remains largely confined to the laboratory or to small human trials.
Tireless cells
Stem cells are the body’s raw material. When an embryo is just 4 to 5 days old, it consists of about 150 stem cells. These embryonic stem cells divide and multiply into all of the cells of the body. Embryonic stem cells are pluripotent (ploo-RIP-uh-tunt), meaning they can self-renew by dividing to form more pluripotent stem cells, or they can differentiate to become more-specialized progenitor cells that can produce a variety of mature cells that form tissues and organs. Once embryonic stem cells begin to differentiate and become more specialized, some of the cells begin moving along a spectrum of identities toward becom-
Putting it into practice
ing an adult stem cell. Adult stem cells are found in small numbers in most tissues and are thought to last a lifetime. They are limited in the variety of cells they can produce. Other types of stem cells also can be obtained from umbilical cord blood and from amniotic fluid. These appear to fall somewhere in between embryonic stem cells and adult stem cells. In 2007, researchers identified another category of stem cells — induced pluripotent stem cells. These adult stem cells are genetically reprogrammed to become like pluripotent embryonic stem cells. Essentially, one of your own, normally nonversatile skin cells can be made into a stem cell that can produce any type of tissue.
Which is best?
Because of their versatility, embryonic stem cells are important for their ability to develop cells and tissues that are difficult to obtain in other ways. However, significant ethical and legal concerns remain. Scientists have made significant strides in coaxing available embryonic stem cells into differentiating into more-specific cells. However, researchers haven’t totally worked out how to guide the behavior of implanted stem cells inside the
body. Stem cells might not survive, or they could form tumors, travel away from the area in need of healing or possibly become an unintended type of cell. With embryonic stem cells, there’s also the issue of potential immune system rejection, similar to organ transplant rejection. Adult stem cells solve the problem of rejection if the stem cells used are your own. However, adult stem cells are scarce in many tissues and can only produce a limited range of cell types. Still, researchers have found adult stem cells in tissues where they were once thought not to exist, and some adult stem cells, such as bone marrow and fat stem cells, are proving rather versatile. Induced pluripotent stem cells could be a game changer. Genetically reprogrammed adult stem cells solve some of the problems with adult stem cells — such as having limited versatility. Since the genetic code of the reprogrammed adult stem cell would be your own, it also would address problems with embryonic stem cells such as organ and tissue rejection. However, getting reprogrammed stem cells to behave predictably could prove to be a challenge. Further, it’s not known if genetic tinkering would cause additional adverse effects that may not occur in an unaltered stem cell. October 2011
The most widely used applications of stem cells for therapy are bone marrow transplants. Other uses include: ■ Manipulating skin stem cells in the laboratory to grow into larger skin patches. These can be grafted onto large wounds. ■ For those who experience damage to the front of the cornea, implantation of cornea stem cells can facilitate proper healing. ■ In certain bone fractures, growth factors can be inserted into the fracture area to stimulate existing stem cells to produce bone. ■ Creating replacement windpipes and bladders. This is done by first creating a structure (scaffold) on which to grow the organ. Creation of more-complicated organs remains only in the very early stages of laboratory development. ■ Mayo Clinic doctors are involved with research guiding bone marrow stem cells to become stem cells that produce heart tissue. These stem cells have been injected into the hearts of people with heart failure or who have had a heart attack. These stem cells may help create new heart tissue, or secrete growth factors that signal existing stem cells to step up their repair efforts. In a small series of cases, Mayo researchers found this process to be safe and feasible, and it appeared to have a modest benefit in terms of heart function.
On the horizon
Early research has been done in many areas such as creating insulinproducing cells for people with type 1 diabetes, regenerating cartilage for those with arthritis, creating dopamine neurons to correct Parkinson’s disease, repairing spinal cord injury and restoring sight in those with macular degeneration. The promise is huge, but most stem cell applications are in their infancy. ❒ www.HealthLetter.MayoClinic.com
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Resilience with age Bouncing back A broken hip. The death of a loved one. A large financial loss. Chronic pain. Difficult and potentially devastating situations can happen to anyone. When adversity or even trauma strikes, it’s normal to experience anger, grief, pain, loss of control or other strong emotions. But when you’re resilient, you’re generally able to keep functioning physically and mentally even when dealing with difficult situations. Your problems may not go away, but it doesn’t take long before you’re able to see past them and find constructive ways to focus your energies, adapt and move forward. In contrast, a lack of resilience may mean that you dwell on problems and limitations, feel victimized or hopeless, withdraw from others, and perhaps turn to unhealthy coping mechanisms such as alcohol. If you’re an older adult, chances are you’ve had a setback or two in your life — and found a way to bounce back. In fact, resiliency is common, and it’s not something that’s simply based on being a strong or stoic person. Rather, there are many factors that contribute to being resilient, many of which can be learned and developed.
Being prepared
The ability to bounce back from adversity is greatly aided by being fit and healthy. That way, you’re better prepared to recover from adversity — whether it’s recovering physically from a health problem, staying hopeful and optimistic despite emotional stress, or having loved ones to support you
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as you get back on your feet. Preparing for resilience includes: ■ Physical activity and a healthy diet — Challenging your body with daily exercise and eating a healthy, plant-based diet help bolster your resiliency by improving your physical strength, stamina, mood and mental health — and by reducing your risk of many diseases. ■ Managing stress — Increased stress before a traumatic event may reduce your resilience. Managing your response to day-to-day stressors may include learning relaxation techniques such as deep breathing or meditation, or other mind and body practices, such as yoga and tai chi. ■ Cultivating healthy social connections — Friends and family can help support and motivate you during a tough time, and they also help give you a sense of purpose as you support them in turn. Make relationships a priority, whether it’s maintaining ties to family or friends, or by participating in a social or religious group. ■ Having something to look forward to — This could be a job, a volunteer role, visits with your grandkids, bridge club, a new opportunity for learning — or any way you can be actively involved with the world. These can help motivate you to stay engaged with life, refocus your thoughts away from your troubles and give you hope. ■ Practicing optimism — It’s never too late to examine thoughts, viewpoints and actions that sour your outlook on life. Look for the positive, count your blessings, forgive, savor good times and simple pleasures, and practice kindness. ■ Cultivating spirituality — You can be spiritual by reflecting on your own life and its purpose, and connecting to something larger than yourself, whether through religious worship, art, music or the natural world. October 2011
When a setback occurs
You may never be totally ready for a difficult situation, but when something bad happens, keep yourself afloat by: ■ Taking care of yourself — Work to maintain good dietary, sleep and exercise habits, and avoid destructive habits such as alcohol. Take time to participate in a hobby or activity that you enjoy. Utilize stress management techniques discussed above and make time to relax, such as by scheduling a massage. Keep up with medical therapies, such as taking medications, and make and keep doctor and dentist appointments. ■ Turning to others for support — Accept the help of friends, family and others. Support groups of people going through a similar situation may help you feel that you’re not alone and can give you motivation and the resources to help you move forward. ■ Being proactive — Develop realistic goals for the near future and do something regularly — even if it’s only a baby step — that allows you to move toward those goals. By taking decisive actions that address your situation, rather than detaching and wishing problems away, you can gain a sense of personal control. ■ Accepting change and remaining hopeful — This helps you avoid dwelling on what’s lost or different and helps you focus on new opportunities or steps that you can take to address the changing circumstances.
Seeking help
Resilience isn’t something you can force to happen by sheer will. If you don’t feel as though you’re bouncing back from a difficult situation — or don’t know where to start — consider talking to your doctor or a mental health care provider for help. ❒
Genetics and drugs Tailoring drugs to you Recently, your doctor prescribed codeine to help manage a racking and painful cough related to an upper respiratory virus. Although you were skeptical — after all, a friend given codeine for a similar viral cough said it didn’t help one bit — the codeine helped significantly. Why do two people respond so differently to the same medication? The way you respond to medications is influenced by many factors, including your age, lifestyle and overall health. Underlying all of that is the role your genes play — not only in how your body processes (metabolizes) medications, but also in how the targets of drug treatment vary genetically. That’s where pharmacogenomics comes in. Researchers are connecting the dots between certain gene variations and how they influence the response to particular medications. Pharmacogenomics offers the hope of predicting whether a drug is more likely to help or hurt you. Pharmacogenomics may also provide new insights into what makes drugs work the way they do.
Individual packaging
The human genome — called DNA — is basically your body’s chemical operating system. DNA directs various types of cells to behave and interact in certain ways. Genes are segments of DNA. Genes are found in all of your cells, and can have many different forms. For example, variations of the gene that codes for eye color determine if you’ll have blue or brown eyes. Your genes also affect how you react to a medication. Gene variations affect the way you me-
tabolize a drug. For instance, you may have a variation that makes a medication stay in your body longer than expected, causing serious side effects. On the flip side, a gene variation may cause a drug to metabolize too fast, making it less potent. Another aspect is genetic variation that affects the target of the gene, which may change your response to a drug. Add to that the possibility that many genes interacting with each other — not just one gene — might determine how you respond to a particular medication.
Beyond trial and error
Being diagnosed with a new condition — such as breast cancer — sets in motion a cascade of important decisions. The foremost decision for many women is which medication or combination of medications will be the most effective treatment for their particular breast cancer. Standard therapy and dosing guidelines help frame that decision. Your doctor also factors in your weight, age, medical history and possibly how others in your family have reacted to the medication that’s under consideration. But even with all of that information, there’s no certainty about how you’ll actually react to the medication. You may encounter only a few side effects, or it could be very difficult. Several return visits to your doctor may be necessary to adjust the dosage or to switch medications. Pharmacogenomic discoveries could someday decrease medication guesswork and speed up treatment. Your doctor would know before starting you on a treatment whether you might be adversely affected or have a better or worse chance of responding to a particular drug. With this information, dosing could be changed or a different drug might be prescribed.
Pharmacogenomics is still in its early stages. Still, a few tests are available to help predict whether certain medications are more likely to produce a good response or a bad reaction. The cytochrome P450 (CYP450) genotyping test looks at a group of enzymes responsible for metabolizing many different medications — including antidepressants, beta blockers, proton pump inhibitors, blood thinners and pain medications such as codeine. The test reveals how well you metabolize a medication. Generally, if your body isn’t able to break down a medication fast enough, the drug can build up in your body and cause severe side effects. Conversely, if you metabolize the drug too quickly, it won’t have a chance to work. The CYP450 test can detect these variations. As a result, doctors can make more-informed prescribing decisions.
The next leap forward
Researchers in the pharmacogenomics field are looking at genomewide associations to determine why some people are affected by a certain condition or drug response and others aren’t. One such association involves aromatase inhibitors — a particular hormone therapy commonly used to treat certain breast cancers. Overall, aromatase inhibitors are well tolerated by most women. However, up to 20 percent of women who take them encounter severe muscle and joint pain. Researchers have discovered an association between certain gene variants that were common to the women who encountered severe pain. From there, the gene trail hooked into another gene that’s a target for drugs used to treat rheumatoid arthritis. The upshot could be new insight into the relationship between estrogens and joint pain. ❒
October 2011
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Second opinion Q:
What’s scabies, and how’s it passed along? My daughter’s family is being treated for it.
A: Scabies is a highly contagious,
itchy skin condition caused by a microscopic burrowing mite. With the initial infection, the mites don’t feed on blood, but on dissolved tissue. After about four weeks, the mite’s presence leads to intense itching in the areas of its thin, irregular burrows, which show up on your skin as tiny lines or bumps. Common sites are between fingers, in armpits, around the waist, around the breasts, around the genital area, on buttocks, knees, shoulder blades, soles of feet, and along the inside of wrists and elbows. Mites can spread during close physical contact and, less often, from sharing clothing or bedding with an infected person, but can sometimes spread with simple physical contact, such as shaking hands. A more-severe form of scabies — called crusted scabies, in which scabies mites and eggs are found in thick crusts of skin — may affect certain high-risk groups. These include people who have weak immune systems, those hospitalized with serious illness and older adults living in nursing care centers. Because scabies is very contagious, treatment may be recommended for all members of a household and other close contacts even if they have no signs of scabies. Those in close contact can carry mites but still not have
the itchy rash. Prescription medications are necessary to treat and eliminate the mites and their eggs. Usually a prescription cream or lotion is applied from the neck down and left on for at least eight hours. Commonly prescribed topical medications include permethrin 5 percent (Elimite), lindane and crotamiton (Eurax). A second treatment one week later may be recommended. Itching may persist for several weeks due to ongoing allergic reaction to mite parts. The oral medication ivermectin (Stromectol) may be prescribed for those who have weak immune systems, those who have crusted scabies or if topical treatments don’t work. To prevent re-infestation or spread of mites, use hot soapy water to wash all clothes, footwear, towels and bedding used in the three days prior to treatment. Dry items in high heat. Seal nonwashable items in plastic bags and put them in the garage or an out-of-theway place for a couple of weeks. ❒
Q:
I’m embarrassed to take my shoes off because of foot odor. I bathe regularly, but it doesn’t seem to make much of a difference. What else would help?
A: Daily bathing is a good start. Using an antibacterial detergent or soap on your feet can help keep the number of odor-causing bacteria on your skin in check. After bathing, thoroughly dry your feet, including between your
toes. Consider using a nonprescription foot powder to help absorb sweat. At bedtime, apply an antiperspirant to the soles of your feet. Choose socks made of cotton or wool. Some cotton blends and wool socks absorb moisture, so they help keep your feet dry. If necessary, change your socks once or twice a day. Shoes made of natural materials allow feet to breathe and can help prevent sweating. Rotate the shoes you wear, allowing them to dry between wearings. If possible, remove the inner sole linings when you’re not wearing the shoes. Go barefoot now and then or at least slip off your shoes. If you still experience problems, consider a visit to your doctor who can determine if another issue — such as excessive perspiration or overgrowth of bacteria — requiring a prescription medication might be the cause of your problem. ❒ Have a question or comment? We appreciate every letter sent to Second Opinion but cannot publish an answer to each question or respond to requests for consultation on individual medical conditions. Editorial comments can be directed to: Managing Editor, Mayo Clinic Health Letter, 200 First St. SW, Rochester, MN 55905, or send email to
[email protected] For information about Mayo Clinic services, you may telephone any of our three facilities: Rochester, Minn., 507-284-2511; Jacksonville, Fla., 904-953-2000; Scottsdale, Ariz., 480-301-8000 or visit www.MayoClinic.org
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