Madely Health Headlines Commentary for February 4, 2010

Source:

Chemical imbalance may explain crib death: study

Low Serotonin Eyed as Mechanism for SIDS

Reference:
Brainstem Serotonergic Deficiency in Sudden Infant Death Syndrome

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Originally published in The Ottawa Citizen July 15, 2003
Original Title: The Stones Wrong Address Part 1: How green is my valley

Part 2
Part 3

The Canadian Museum of Nature has exquisite colourful and exotic-looking crystal, mineral and stone collections. The human body also harbours interesting mineral, stones and crystal deposits.

Stones commonly form in the gallbladder, kidney and salivary glands. Crystals form in several joints most, notably the knee and the big toe as seen with gout. Starting with the gallbladder, we will look at how each arises, where they collect and how to treat and prevent serious complications.

The gallbladder is a seven to 15-centimetre muscular sac-like organ located in the upper right side of the abdomen hanging off the underside of the liver.

A duct system connects the gallbladder to the liver, pancreas and small intestine. It functions as a reservoir for bile salts, cholesterol and other fatty substances produced in the liver. Bile aids in digesting of fatty foods. The gallbladder contracts after a fatty meal, pumping bile into the intestine.

Gallstones form under conditions that promote a hardening of these substances. Surgical removal of the gallbladder, or cholecystectomy, is the most common abdominal surgery in medicine.

Gallstones come in two types: cholesterol and pigment. Eighty to 90 per cent of all gallstones are cholesterol stones. Pigmented stones contain less than 20 percent cholesterol and account for the remaining ten to 20 per cent.

There are numerous risk factors for gallstone formation. People of Scandinavian, Native American Pima Indian, Hispanic, and western Caucasian backgrounds are at greater risk. So are those with a maternal family history of gallstones. Pregnant women and women in general are at greater risk, as are middle-aged and obese people.

Those who have fasted frequently and undergone rapid weight loss are also at risk. So are those who have taken the birth control pill, postmenopausal estrogens, progesterone and cholesterol-lowering fibrates (Gemfibrozil, Bezalip, Lipidil Micro, Lipidil Supra) among others. Cholesterol lowering statins do not cause gallstones

Other risk factors include high levels of triglyceride (a type of fatty molecule), diabetes, Crohn’s disease, cirrhosis (scarring) of the liver and bile duct and Sickle cell disease among other conditions associated with rapid destruction of red blood cells.

Sixty per cent of people with gallstones do not have symptoms and are often unaware they have them. Usually gallstones are found during an abdominal ultrasound done for other medical reasons.

If someone experiences a gallstone attack, the likelihood of another is about 70 per cent.

Symptoms occur when the stone either leaves the gallbladder and winds its way down the common bile duct into the intestine or becomes lodged in the neck of the gallbladder. Typically, the pain will begin suddenly, intensify over 15 minutes and last for about three hours.

Pain typically localizes just below the bottom tip of the breastbone and shift toward the upper right-hand side of the abdomen. Palpating this area produces more discomfort. The pain may radiate directly to the upper back or to the back of the right shoulder.

Other symptoms can include nausea, vomiting, and intolerance to fatty foods. This sudden attack is biliary colic although the term ‘colic’ is a misnomer since the pain is steady and does not wax and wane. Once the gallbladder relaxes several hours after eating, the stone will often fall back into it and the pain subsides.

The most common imaging test to diagnose and screen for gallstones is an abdominal ultrasound. There are other tests available for specific studies of gallbladder function. X-rays play a lesser diagnostic role since they can only detect mineral-rich pigmented stones.

Of the 40 per cent of people who develop symptoms of gallstones, 70 to 80 percent experience biliary colic and ten per cent will develop infections and inflammation of the gallbladder (acute cholecystitis).

The gallbladder is likely to become infected and/or inflamed if the stone partially or completely blocks the small duct that leads out of it. Fever can develop and pain lasts longer than three hours. Acute cholecystitis is a surgical emergency. In many elderly patients, there may be no fever and pain, only some local tenderness in the right upper quadrant.

The goal is to prevent the complications of duct blockage: perforation of the gallbladder, infection or inflammation of the gall bladder or bile duct, inflammation of the pancreas (pancreatitis) or liver damage.

Next week’s column will look at the treatment and prevention of gallstone complications.

Related articles:

1. Travelling gallstones warrant emergency care
2. Kidney stones among life’s most painful experiences
3. Wednesday House Call, June 30, 2010

Originally published in The Ottawa Citizen May 27, 2003
Original Title: Don’t sweat the small stuff

You can prevent heat-related illness with an understanding of how summer heat affects your body.

First, the biology lesson. The body has four ways to dissipate heat: conduction, evaporation, radiation and convection.

Conduction is the transmission of heat through a substance like blood, water or other tissues. Muscles that are warm from exercise can dissipate heat directly to the skin surface.

Blood can absorb great quantities of heat from the muscles and other tissues. It will return to the heart and then circulate to the small blood vessels in the skin. During exercise, the blood vessels dilate to allow greater quantities of blood to transfer heat to the skin surface.

The skin will radiate heat into the surrounding air and environment just like a space-heater. Sweat on the skin surface can absorb the heat and evaporate to reduce body temperature.

As the air warms around the body, it will rise. Cooler air moves in to replace it and absorbs body heat. This cycle is called convection and explains why fans help cool us.

Each mechanism works best within a specific temperature range. At temperatures less than 20C, radiation, convection and conduction will dissipate most generated body heat. Above 20C, sweat evaporation is the primary means of dissipating heat.

Children do not sweat as much as adults and produce more heat for the same level of activity. They need to generate greater levels of heat before they do sweat.

Overweight individuals do not dissipate heat as well as those of normal weight. The elderly have a decreased thirst response, and a reduced ability to circulate blood to the skin surface. Their blood vessels do not dilate as well as younger adults. Some medications can contribute to the risk of heat illness.

As temperature and humidity increase, evaporation becomes less effective. On a hot city day, core body temperatures increase because of radiant heat from the sun and hot concrete surfaces.

Evaporation accounts for 85 per cent of heat loss during vigorous exercise (a 70 kilogram athlete can lose one to two litres of sweat per hour).

Failing to replace water and salt loss further compromises conduction and evaporation.

Adapting to the effects of heat during exercise over a specific time is termed acclimatization — adapting to the increased demand to dissipate heat. Fluid replacement is essential for this process to work.

There are five types of heat-related illness. From mild to severe they are:

1. heat swelling (edema);
2. heat cramps;
3. fainting from heat (heat syncope);
4. heat exhaustion;
5. heat stroke.

Heat edema occurs in people who have not undergone acclimatization. Fluid leaks out into the tissues of the feet especially when standing for prolonged periods. To reverse the process, elevate your legs.

Heat cramps are painful abdominal, arm or leg muscle spasms occurring when too much salt and water is lost. This is a warning sign of pending heat exhaustion. Drinking water, juice or sport drinks and eating salty foods will relieve the cramps.

Fainting is a risk if there is no cool-down period after exercise. Blood pressure can drop when quickly transferring from a sitting to standing position. Lay flat and elevate your legs to reverse this condition.

Heat exhaustion occurs with excessive sweating in a hot humid environment. Body fluid volume is lost. The core body temperature increases from 38C to 40.5C. Symptoms include profuse sweating, fatigue, headache, dizziness, visual disturbances, lack of appetite, nausea, vomiting, vertigo, chills, muscle weakness, rapid heart rate, low blood pressure and skin flushing.

Move a person with heat exhaustion to a cool area. Applying cool water-soaked cloths helps. Elevate the legs. Those who are alert need one litre of oral fluid replacement per hour for two to three hours. If the person is disoriented or unresponsive, a trip to the emergency room and a thorough medical examination is in order.

Heat stroke is the most severe form of heat-related illness. Body temperature exceeds 40.5C and leads to multi-organ damage and failure. Altered mental status is a critical determinant of heat stroke. This medical emergency needs prompt evaluation and treatment.

Preventing heat-related illness is straightforward:

• Stay in air-conditioned surroundings if possible.
• Drink lots of water before, during and after any outdoor activity.
• Avoid drinks with caffeine or alcohol. You will lose fluid via urination.
• Increase the amount of time you spend outdoors every day little by little.
• Take frequent rest breaks while outdoors on hot days.
• Avoid direct sunlight and stay in the shade when possible.
• Wear light-coloured, loose-fitting, open-weave clothes.
• Avoid activities that require using a helmet.
• Try scheduling activities or workouts early in the morning or late evening. Avoid heavy outdoor activity between 10 a.m. and 6 p.m.

Enjoy your summer.

© Dr. Barry Dworkin 2003

Related articles:

1. Don’t Sweat the Small Stuff
2. Elderly vulnerable to ill effects of heat waves
3. A primer on heat-related illness as Ottawa experiences its first heat wave of the season

Originally published in The Ottawa Citizen November 5, 2002
Original Title: Every Breath You Take
Part II: Medication only part of asthma care

Asthma management continues to be a problem for some patients. This is borne out by the telephone call from a patient who frequently runs out of their Ventolin puffer. A review of their chart shows repeat monthly or bimonthly renewal requests; a red flag denoting poor asthma control.

Despite newer medication formulations and treatment protocols, asthma rates continue to climb. The Centers for Disease Control review of rates during 1982 to 1992 showed an increase of 52 percent (34.6 to 52.6 per 1000) for people between the ages of five to 34 years. The greatest increase occurs in people under 18 years of age.

The next two columns will review what causes asthma, its diagnosis and treatment in children and adults. It will provide the tools to improve your ability to take charge of this condition.

Asthma is an inflammatory disease that plugs up the lungs and obstructs the ability to breathe. Its principal causes include genetic factors, allergies, chronic exposure to cigarette smoke and other chemical airborne irritants.

The bronchi are the tubes that carry air into the lungs. Lining their inside walls are cells that produce mucous. Other cells have sweeping and cleaning functions that clear the airway of contaminants, viruses and bacteria.

Elastic bands of muscle wrap around the bronchi’s outer walls. Their function is to dilate and constrict the bronchi in response to environmental or physiological factors. The terms for these actions are bronchodilation and bronchoconstriction. This action is important for proper lung function.

For example, inhaling cold winter air can cause the airways to produce mucous and bronchoconstrict. This increases the time to fill the lungs with air. The net result is more time to warm the air to prevent a reduction in core body temperature.

A combination of factors in asthma impairs normal breathing function. The bronchi become irritated and swollen under different conditions thereby causing bronchoconstriction and abnormal amounts of mucous secretions. The swelling of inner bronchial wall decreases its diameter. The net result is airflow obstruction.

Asthma triggers include exposure to allergic substances (allergens), colds and flu, pneumonia, aerobic exercise, cold air and smoking.

It is easy to overlook or ignore the initial physical symptoms associated with asthma. Many people do not seek medical attention for that intermittent nagging cough. They adapt to their symptoms and assume it is their normal state.

Most people associate wheezing with asthma. Although a common adult symptom, it can be absent in some young children. Children may have a deep hacking non-wheezy nighttime cough. The coughing fits can be so strong that the child vomits thereafter. Many parents will bring their child to the office not for the cough but rather because of the vomiting.

The spirometer is a tool used to diagnose asthma. It measures a wide variety of lung functions. These measurements determine if there is any airway obstruction during rapid exhaling and inhaling through the device.

If there is obstruction Ventolin, a bronchodilator medication, may be administered to the patient prior to repeating spirometry. A measurable improvement in lung function may indicate asthma.

Young children are unable to perform spirometry. Careful observation, physical examination and a detailed medical history can help establish the diagnoses.

To wit, some factors are particularly useful in establishing a diagnosis in young children. Does the child cough at night, during physical activity, playing outside in the cold winter air or when they catch a cold virus? Do they wheeze more than three times a year? Do they have eczema? Do the parents smoke in the house or car? Is there a family history of asthma or eczema?

Often, physicians will initiate a trial of a Ventolin inhaler or liquid Alupent to see if it relieves the cough and wheezing. If successful it may indicate asthma.

There is a straightforward way to determine whether asthma treatment needs adjustment. All asthmatics that use their bronchodilators (Ventolin and Airomir (salbutamol), Apo-Salvent and Berotec) more than two to three times a week have by definition unstable asthma. This instability increases the risk of a more severe asthma attack. More definitive approaches are in order.

Next week we will look at the five principles of effective asthma treatment;

• individualized continuing care,
• the ways the medications work in preventing and relieving symptoms,
• medication side effects and how to manage them,
• preventive treatment to reduce inflammation when symptoms are absent,
• early treatment to reduce inflammation when symptoms are present.

Get a head start and consult your doctor should you be using your bronchodilator medication more often than usual.

Related articles:

1. A reader asks about asthma
2. Medication only part of asthma care
3. How to control asthma

Originally published in The Ottawa Citizen May 28, 2002

Original Title: Just a Spoonful of Sugar

At Montreal’s Jewish General Hospital, the chief of emergency medicine, Dr. Marc Afilalo always emphasized the importance of knowing the pathophysiology of diseases. ‘Pathophysiology’ refers to the abnormal physical processes that cause disease: in short, how things work.

Patients face this conundrum daily. They take medications for conditions that they know are serious but are unaware of how the disease inflicts harm upon their body.

One such disease is type 2 diabetes formerly known as non-insulin dependent diabetes. Most people are aware that diabetes causes abnormally high blood sugar levels (hyperglycemia) but what is the reason? What happens if it remains poorly controlled or untreated?

Sugar (glucose) is the body’s main fuel source. The body has to be able to store, transport and deliver it depending upon the demands of the cells. Normally sugar is stored in the liver and muscles. The liver also produces glucose.

After a meal, sugar is absorbed from the intestine into the blood stream. In response, the pancreas secretes insulin produced by cells called beta-cells. Insulin helps the muscle, liver, fat and almost all other tissue cells absorb the sugar. It binds to an insulin receptor (like a key in a lock) on the cells’ surface opening the door for the sugar to enter.

There is evidence to suggest two mechanisms are responsible for the development of diabetes.

The first is a defect in the beta-cells ability to produce insulin. The second is the liver and muscle insulin receptors weakly respond to insulin. The liver releases more sugar because of this effect. More insulin is required to get the cells to absorb sugar. It is like having a rusty lock requiring several attempts inserting and turning the key until it finally opens.

The beta-cells try to compensate by producing more insulin to keep the sugar levels normal. However, the end result is that they burn out and insulin production fails.

Glucose is a sticky molecule. It binds to the body’s many cell types causing serious damage over time. Of particular importance are those found in the kidneys and arteries of the eye, brain, heart, kidneys and lower legs and feet.

The kidneys are responsible for filtering and removing toxins from the blood. They also maintain the body’s salt and water balance. Sugar will damage the filters like poking large holes into a sieve destroying kidney function. Salt, protein and water imbalances can cause swelling of the legs, hypertension and heart failure among others.

The inner lining of the artery is called the endothelium. Glucose can bind to this layer. This makes it easier for cholesterol and blood clotting factors to form a clot (thrombus) or plaque leading to eventual arterial blockages in the heart, brain, eyes and lower legs and feet. High insulin levels can also stimulate the growth of the endothelial cells, increase the stickiness of a blood clotting cell (platelets) and cause the arteries to constrict or narrow (vasoconstriction).

Heart attack and stroke risk increase. Areas of the retina can die causing partial to complete blindness. Oxygen delivery to the lower legs and feet is reduced. The nerves that provide information about the foot’s position and touch sensation malfunction (peripheral neuropathy) that can lead to foot injury and skin ulcers. The skin on the shins becomes smooth and shiny because of hair follicle death.

Other factors that complicate this process are elevated cholesterol levels, hypertension, obesity, smoking and family history of heart disease and stroke.

Hypertension increases the strain on the arterial walls and can cause a piece of the clot to break off (embolus) and travel to the brain causing a stroke. It can hasten the complete blockage of the main coronary arteries leading to heart attack.

Obesity will increase the demand for insulin. A larger body mass implies many more cells each with its own insulin receptors. More receptors mean more insulin is required to maintain normal sugar levels. Further these cells can be insulin resistant. The beta-cells cannot keep up with the increase in demand for insulin: hyperglycemia worsens.

The nicotine from cigarettes causes vasoconstriction increasing the risk of heart attack, stroke and loss of the lower limbs.

Many people have a combination of these risk factors. Diabetes is an insidious and destructive disease causing tremendous harm and incapacity (morbidity) and eventual death (mortality).

What if you were a researcher and you had the resources necessary to develop diabetes medications? Given the pathophysiology of diabetes, what strategies would you use to alter the various processes outlined above?

Next week’s column will focus upon treatment and demonstrate how scientific research propels the development of new and innovative strategies in the battle against diabetes.

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1. Great variety of drugs helps treatment of diabetics
2. Lower cholesterol to prevent stroke, heart disease
3. New understanding behind the mechanism of diabetes

Originally published in The Ottawa Citizen April 9, 2002
Original Title: Blowing a Gasket

High blood pressure (Hypertension) is another silent disease with catastrophic results if left untreated. Heart disease is the number one cause of physical and emotional harm (morbidity) and mortality in Canada and the United States. Despite the myriad of information targeted to Canadians, the problem grows worse. Money and human resources are stretched to the limit to combat cardiovascular disorders.

Of Canadians between 18 to 70 years of age 22 percent or 4.5 million people have hypertension. It is a condition that exerts it effect over time. Damage accumulates and organs such as the heart, kidneys and brain eventually fail.

Left untreated, it virtually guarantees an increased risk of stroke (cerebrovascular disease), heart attacks and angina (cardiovascular disease), congestive heart failure, kidney (renal) failure and poor circulation to the feet, lower legs and hands (peripheral vascular disease).

Hypertension is insidious. About 98 percent of all hypertension has no discernable cause and is called Essential Hypertension. There are no symptoms in people with mild to moderate levels of hypertension while headache and vision changes occur with severe levels.

Consider the following challenge. You have five seconds to exhale all the air in your lungs. What effort is required to completely exhale through an empty paper towel roll versus a straw? Obviously, it would require a more forceful effort to get the same volume of air through the straw in five seconds compared to the wide paper towel roll. The straw’s airflow resistance is greater than the roll. The arteries are no different.

When the artery’s resistance increases due to hardening or loss of their ability to stretch in width (elasticity), the heart has to work and pump more forcefully to circulate the same volume of blood throughout the body. Like any muscle that works harder, the heart’s left ventricle increases in size (left ventricular hypertrophy) to compensate for the increased workload. This mechanism works for a while but at a price. There are limits to heart size. Eventually the heart begins to irreversibly fail leading to congestive heart failure (a five-year mortality rate of 50 percent).

Another long-term effect of high blood pressure is damage to the smaller arteries and even smaller arterioles in the kidneys, brain and extremities. The kidney has millions of microscopic filtration systems called glomeruli. These effectively remove toxic waste products of metabolism from the body. The glomeruli are disrupted and destroyed leading to kidney failure. The arteries in the brain (cerebral arteries) can rupture leading to stroke. Less blood circulates to the feet and toes resulting in pain, loss of skin sensation, difficulty walking and in some situations, loss of limb(s).

All these risks and symptoms worsen with diabetes, smoking, high cholesterol, obesity and lack of exercise. Many of hypertension’s effects can be minimized and for some reversed. Normalization of blood pressure before the heart muscle fails can reverse the hypertrophy and prevent heart failure. Treatment in people under 60 years old reduces the risk of stroke by 42 percent and heart attack by 14 percent. People over 60 see a reduction of overall mortality by 20 percent, cardiovascular mortality by 33 percent, stroke incidence by 40% and coronary artery disease by 15 percent. These are amazing rate reductions.

So why do so many people continue to suffer and die from cardiovascular complications? Of the group of 4.5 million Canadians with hypertension only 16 percent are treated and controlled. Twenty three percent are treated and uncontrolled. Most worrisome are the 19 percent of this group that is aware they have hypertension but remain untreated and that the remaining 42 percent are unaware that they have hypertension.

There is no reason for people to suffer so needlessly from this condition. Treatment is effective with most people reporting minimal side effects. There is no end to the refrain that our health care system is under pressure to provide more services for less money. There are fewer health professionals available to provide care for end stage heart and kidney disease.

The cost of treating end-stage heart disease and renal failure is staggering. There are over three million people lined up to become future members of the end-stage club. There are billions of dollars in potential savings per year if all hypertension would be treated. These funds could then be redirected towards other areas of our health care system in desperate need of help.

There are many people who should see their doctor to find out if they suffer from hypertension. If you have not seen you doctor in years, do so. You may be one of those 42 percent. Do not join those 19 percent who know they have hypertension and do nothing about it. Appropriate lifestyle changes and medical therapy will reduce future disability and hardship. And that’s 100 percent for sure.

For more information: The Canadian Hypertension Society www.chs.md.

Related articles:

1. Stroke out the numbers
2. Women should worry more about cardiovascular risks
3. Dealing with diabetes means understanding how it works