Month: August 2016

The Sun — America’s Leading Cause of Cancer

By Mark A. Kelley, MD |08/23/16

Skin cancer is the most common cancer in the United States. Here are some facts:

•Over 3 million Americans are treated for skin cancer every year.

One in five Americans will develop skin cancer during their lifetime.

•Skin cancer is preventable and easy to detect.

•When caught early, this cancer is usually curable.

Skin cancer is caused by sunlight damage to the skin. The only way to prevent it is to stay out of the sun, or block the sun’s rays.

People with fair skin are more vulnerable to skin cancer. Those with dark complexions have some natural protection since their skin filters out some of the sun’s rays. Nonetheless, people of color can still get skin cancer.

The sun’s ultraviolet rays can damage the DNA of skin cells. These cells may grow abnormally and eventually become cancerous. This transformation may evolve slowly over many years or may occur earlier in life, particularly if sunlight exposure has been intense.

Sunlight can also lead to another problem–premature wrinkling of the skin.  Sun worshipers believe that a tan is healthy. In reality, a suntan is a sign of the skin injury. If it continues, the damage can destroy the foundations of the skin, and make it look like leather. Tanning also triples the likelihood of developing the most dangerous form of skin cancer, melanoma.

A melanoma starts as a pigmented skin lesion. Early detection and removal can cure this malignancy. However, if untreated, melanoma can spread to other parts of the body and cause death.

The other types of skin cancer are less aggressive and spread slowly to the surrounding tissue. The most common are basal cell and squamous cell carcinoma. These cancers are rarely fatal and in early stages, are easy to remove.  If ignored, they can invade deeply and widely, making surgical removal challenging.

To prevent skin cancer, protect your skin from sunlight:

1. Limit your exposure to the sun. The sun’s rays are most intense between 10 am and 4 pm.

2. If you must go out in the sun, block the sun’s rays with “cover-up” garments and/or with sunblock.

3. Use sunblock that has sun protection factor ratings (SPF) of 15 or more.   An SPF of 15 means that it would take you 15 times longer to get sunburn with the sunblock, compared to none at all.

4. Follow the directions for applying and reapplying the sunblock product. Sunblock can lose its effectiveness after a few hours. It can also be removed by perspiration or swimming.

5. Avoid indoor tanning salons. Research has shown that those using tanning beds have an alarming increase in skin cancer including the most deadly form, melanoma. Click here for more information.

Screening for Skin Cancer

The benefits of routine skin cancer screening are controversial. However, most experts agree that anyone with a suspicious skin lesion or with a history of skin cancer should seek medical advice. Click here for details.

More information on skin cancer can be found at the National Institutes of Health and the Skin Cancer Foundation.

Summer Heat — A Dangerous Health Risk

By Mark A. Kelley, MD |08/15/16

Weather cross the U.S. has been unusually extreme this summer. Most regions have experienced high temperatures, often accompanied by high humidity. Summer heat can be a serious health hazard. This is why weather forecasters issue “heat alerts”, warning people to stay in cool environments.

Historically, heat waves have caused many deaths, especially among the elderly. Heat-related illness has also claimed the lives of younger victims, such as athletes and military trainees. These tragedies are preventable.

Our bodies are vulnerable to heat or cold. Major organs, blood flow and biochemical mechanisms only work within a narrow range of internal body temperature.

The human body can make some adjustments to outside temperature change. When it is cold, blood flow shifts away from our limbs to internal organs to preserve heat.  This is why our hands and feet feel cold.

In hot weather, our bodies do the opposite. We cool off by shifting more blood flow to our skin while producing sweat. When sweat evaporates, it acts like a natural sprinkler system and pulls heat away from the skin. . The extra blood flow to the skin speeds up the cooling process by moving “hot blood” from inside the body to the cooler surface of the skin.

This works well except when the environment is unusually hot and humid.

In that situation, sweat does not evaporate because of the high humidity. This blocks the body’s best method to eliminate body heat, and can lead to high internal body temperatures.

There are two stages of heat-related illness … and both have warning signs.

In the first stage called “heat exhaustion” the patient sweats profusely with cold clammy skin and may feel faint or nauseous. If this continues, the result can be dehydration and failure to sweat. Without any sweat, body temperature can climb quickly.

This can lead to the second and most dangerous stage, called “heat stroke”. The victim becomes confused and may have seizures or trouble walking. If left untreated, heat stroke can result in major organ failure and death. Heat stroke is an emergency that requires immediate medical treatment.

These serious conditions can be prevented. The concept is simple–-avoid environments that raise body heat and keep well hydrated. Here are some tips:

1. Avoid the high heat and humidity by staying out of the sun and seeking cool, well-ventilated, preferably air-conditioned spaces. This will keep your body heat down.

2. Avoid vigorous outdoor exercise in extreme heat. Exercise in these conditions is risky. It quickly raises body heat while the hot, humid air prevents cooling and promotes dehydration. If you must exercise outdoors, choose times early or late in the day when the temperature is lower. This is the strategy used by high performance athletes.

3. Take special precautions if you are elderly or live in an apartment. The elderly are particularly sensitive to extreme heat. During heat waves, apartments and other closed dwellings can become dangerously hot if they do not have fans or air conditioning. In these situations, it is wise to seek temporary shelter in a cooler place, either with friends or relatives or in cooling shelters provided by municipalities.

4. Drink lots of fluids whether or not you are thirsty. Staying hydrated helps your body cope with the heat.

With these sensible approaches, you can safely ride out the heat wave and look forward to cooler days.

For excellent recommendations on prevention, recognition and treatment of heat exhaustion and heat stroke, see the Centers for Disease Control website.

For more detailed information about the hot weather and health, see E-medicine.

How to Fight Zika — Lessons from the Panama Canal

By Mark A. Kelley, MD |08/08/16

The Zika virus continues to capture headlines. Zika virus has been found in Puerto Rico and now in a Miami Florida neighborhood.

Is this the beginning of a major epidemic? Not likely – if we follow the lessons of the Panama Canal.

I recently visited Panama and its famous canal that links the Atlantic and Pacific Oceans. The canal was built between 1880 and 1914 at the cost of many lives. Over 30,000 workers perished, most of them dying from tropical diseases. The most deadly were malaria and yellow fever. The latter could kill some victims within a week.

The tropical disease epidemic in Panama was stopped without the use of any vaccines or drugs. The key was understanding how mosquitoes spread these diseases to humans. Female mosquitoes need blood nourishment to lay their eggs. Infected mosquitoes can transmit the diseases to humans when they sample human blood. Eliminating mosquitoes prevents the disease.

Zika virus, known for almost seventy years, belongs to a group of tropical viruses transmitted by mosquitoes. Among them are yellow fever and dengue fever.
Until recently Zika was not considered a major public health problem because it rarely caused problems in humans.

Now Zika has changed and become dangerous. When the virus is transmitted from an infected woman to her fetus, the infant may be born with major birth defects, particularly of the brain. At the moment we have no drugs or vaccines to fight Zika.

This sounds like the Panama problem in the early 1900s. What stopped the epidemic back then?

The answer came from understanding the aegypti mosquito, the major carrier of these viruses. Each mosquito lives only 2-4 weeks. The female lays hundreds of eggs that hatch immediately upon contact with water. In dry conditions, these eggs can survive for 12 months. The resulting larvae emerge as adult mosquitoes in about ten days.

Aegypti mosquitoes have several important characteristics.

1. They stay close to human dwellings and need very little water for their eggs. These bugs prefer to be close to their victims and hide in and near dwellings –not in the jungle. They love stagnant water to lay their eggs. Human dwellings, with flowerpots and gardens, sinks and toilets, are perfect. During the Panama Canal construction, mosquitoes were happily breeding in the inkwell of the chief physician!

2. The typical female travels no more than a quarter mile during its lifetime. The only way for Zika virus to leave the neighborhood is by “hitching a ride” with a human. In the Miami outbreak, the “neighborhood” where Zika was found is about 10 blocks wide and 20 blocks long. An infected human who leaves this “Zika zone” may bitten by a mosquito in a new location that is “Zika-free”. If that local mosquito becomes infected, it can pass Zika to victims in the new neighborhood.

3. They like to bite humans during the day. This makes prevention more challenging for those who leave their home during daytime.

What stopped the Panama Canal epidemic a century ago? Public officials declared war on these mosquitoes with an aggressive action plan:

• Every house and neighborhood was inspected regularly to eliminate standing water and stop mosquitoes from breeding. All water containers were cleaned weekly to kill any eggs or larvae.

• Irrigation ditches and swampy areas near homes were drained.

• To prevent spread, yellow fever patients were kept in isolation from mosquitoes.

• Workers and the general public covered up with long sleeves and pants to reduce the chance of mosquito bites.

The plan worked. In less than one year, the yellow fever epidemic ended. .

Today, we have many more tools to fight this virus – window screens, air conditioning, municipal sanitation, and effective insect repellant. Also many regions in the U.S. either are too dry or too cool for the aegypti mosquito to thrive.

We still have much to learn about Zika. One surprise is that Zika can be transmitted by sexual contact. This makes things more complicated and prevention recommendations are still evolving. Hopefully, a Zika vaccine may eventually emerge, as happened with yellow fever.

Meanwhile, the lessons of the Panama Canal still hold true:

• Eliminate standing water near humans.

• Prevent mosquito bites by staying inside screened dwellings. When outside, wear clothing that covers the skin and use insect repellent.

These measures are effective. During a five-day visit to Panama City, none of my family and friends was bitten by a mosquito. In fact we never saw one.

For the most accurate and up-to-date information about Zika, check the Centers for Disease Control website. There you will find details about prevention, transmission, and Zika in Florida and other locations.

What is Precision Medicine?

By Mark A. Kelley, MD |08/01/16

In his State of Union address this year, President Obama announced a federally funded program called ”Precision Medicine”. This $215M project is designed to improve disease treatment and prevention by studying the variability in genes, the environment, and lifestyle for each person. A “cohort” of one million volunteers from different parts of the nation will followed over a number of years.

This project resembles the famous Framingham Heart Study, which began almost 70 years ago. That study has provided major insights into the causes of heart disease by following patients over many decades.

In this era, we have many more tools to improve our understanding of how diseases evolve over time. We can track massive amounts of information about patients and analyze their genes. We also have new electronic communication and monitoring tools. The hope is that we can find better ways of prevention, detection and cure of diseases. Already, medical research is facing some important challenges. Here are several examples.

Inherited disease is more complicated that we thought. Medical science has achieved major breakthroughs in understanding how the human genome behaves. Genes control most of the processes in our bodies and slight changes in those genes can cause problems. Some inherited genes have been known for decades – such as sickle cell disease and cystic fibrosis. However, the system is much more complex than ever imaged. Only recently have we begun to understand how inherited genes cause disease.

Genes can control our response to prescribed drugs. Some drugs, such as those for conditions like hypertension and blood clots do not work the same for everyone. Many patients may need higher (or lower doses) and for some, the drug does not work at all. Research suggests that these variances may be due to different genes that control the way the drug interacts with our bodies. How do we know which drugs are best for each person? Should we test everyone for genes that control response to prescribed drugs?

Genes can become abnormal and trigger disease. Curing cancer is at the core of the Precision Medicine project. All cancer is from the uncontrolled growth of cells. In many cancers, genes that control cell growth no longer work normally and the result is a tumor. We do not understand how or why this happens. In some cases, genetic analysis of the patient’s tumor reveals which genes are defective and therapy can be developed to block the effects of these abnormal genes. The influence of genes on human disease is the hottest area of medical research. Precision Medicine will help us understand much more about these processes.

How are diseases related to the environment, including social factors? We know much about toxins and other environmental risks but we need to learn more. The influence of social factors on health is not well understood. Poverty, education, and life style can affect health but the details are lacking. For example, is poverty a risk factor for hypertension when you exclude all other factors except poverty itself?

Fortunately, we have the tools to improve our understanding of these issues. Studying the human gene has become very sophisticated and less expensive. With this technology, we may learn how and when genetic testing is useful in a large population. Supercomputers can analyze enormous volumes of information about patients over many years. This may reveal important clues on disease patterns and risks for individual patients.

We in the United States are a very diverse population and each of us is uniquely different. With Precision Medicine, we may better understand how to provide the best care for every individual.

For more information about Precision Medicine, go to the National Institutes of Health website or the White House webpage.

If you are interested in enrolling in the project, contact the NIH Precision Medicine participation website.

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