Text 8. What is an ultrasound?

Ultrasound produces sound waves that are beamed into the body causing return echoes that are recorded to "visualize" structures beneath the skin. The ability to measure different echoes reflected from a variety of tissues allows a shadow picture to be constructed. The technology is especially accurate at seeing the interface between solid and fluid filled spaces. These are actually the same principles that allow SONAR on boats to see the bottom of the ocean.

What is ultrasonography?

Ultrasonography is body imaging using ultrasound in medical diagnosis. A skilled ultrasound technician is able to see inside the body using ultrasonography to answer questions that may be asked by the medical practitioner caring for the patient. Usually, a radiologist will oversee the ultrasound test and report on the results, but other types of physicians may use ultrasound as a diagnostic tool. For example, obstetricians use ultrasound to assess the fetus during pregnancy. Surgeons and emergency physicians use ultrasound at the bedside to assess abdominal pain or other concerns.

A transducer, or probe, is used to project and receive the sound waves and the return signals. A gel is wiped onto the patient's skin so that the sound waves are not distorted as they cross through the skin. Using their understanding of human anatomy and the machine, the technician can evaluate specific structures and try to answer the question asked by the patient's physician. This may take a fair amount of time and require the probe to be repositioned and pointed in different directions. As well, the technician may need to vary the amount of pressure used to push the probe into the skin. The goal will be to "paint" a shadow picture of the inner organ that the health care practitioner has asked to be visualized.

The physics of sound can place limits on the test. The quality of the picture depends on many factors.

Sound waves cannot penetrate deeply, and an obese patient may be imaged poorly.

Ultrasound does poorly when gas is present between the probe and the target organ. Should the intestine be distended with bowel gas, organs behind it may not be easily seen. Similarly, ultrasound works poorly in the chest, where the lungs are filled with air.

Ultrasound does not penetrate bone easily.

The accuracy of the test is very much operator dependent. This means that the key to a good test is the ultrasound technician.

Ultrasound can be enhanced by using Doppler technology which can measure whether an object is moving towards or away from the probe. This can allow the technician to measure blood flow in organs such as the heart or liver, or within specific blood vessels.

Text 9. When Medicines Become a Risky Mix.

Many people take several medicines to treat different conditions at the same time. Each medicine may be safe to use by itself, yet together there could be dangerous or even deadly drug interactions. One example happened last year. Rhythm-and-blues singer and songwriter Gerald Levert died at his home in Ohio. A medical examiner found that the death was accidental, caused by a mixture of medicines. He was forty years old. The drugs in his blood included the painkillers Vicodin, Percocet and Darvocet as well as the anxiety drug Xanax. These all require a doctor's approval. Other medications that are sold without the need for a prescription from a doctor were also found in his blood.

Earlier this year there was a government report on drug interactions. Researchers said deaths from accidental drug combinations in the United States increased almost seventy percent. That was between nineteen ninety-nine and two thousand four. In two thousand four, nearly twenty thousand people died from accidental drug poisonings. The problem is now the second most common cause of accidental death in the United States, after motor vehicle accidents.

Harmful drug interactions are a growing problem throughout the world. The increase is partly a result of patients being given more drugs and more combinations of drugs than ever before. For example, people infected with the AIDS virus often develop tuberculosis. These conditions should be treated together. In some countries, aging populations mean more sickness, which means more need for medicine.

Experts say patients should talk with their doctor and pharmacist before taking new medications. These include drugs that do not require a doctor's approval as well as herbal treatments. Even some foods can interact with medicines in ways that may be helpful or harmful.

Alcohol may be unsafe with medicines including common painkillers like acetaminophen or ibuprofen. The combination can raise the risk of liver damage or stomach bleeding.

There are many resources on the Internet about drug interactions. However, it is always a good idea to confirm health information from the Internet with a medical professional.

Text 10. An allergy.

An allergy is an unusually strong reaction to a substance. Many things can cause allergies. The most common cause is pollen. Trees usually produce pollen in the spring as part of their reproductive process. Pollen also comes in grasses in the summer and weeds in the fall.

Other causes include organisms such as dust mites and molds. Chemicals, plants and dead skin particles from dogs and cats can also cause allergic reactions. So can insect bites and some foods.

The most common kind of allergic reaction is itchy, watery eyes and a blocked or watery nose. Allergies can also cause red, itchy skin. Some reactions can be life-threatening -- for example, when breathing passages become blocked.

Avoiding whatever causes an allergy may not always be easy. Antihistamine drugs may offer an effective treatment. Another treatment is called immunotherapy. A patient is injected with small amounts of the allergy-causing substance. The idea is that larger and larger amounts are given over time until the patient develops a resistance to the allergen.

In the United States, experts estimate that up to four percent of adults and up to eight percent of young children have food allergies. Every year these allergies cause about thirty thousand cases of anaphylaxis, a severe reaction that requires immediate treatment. It can result in trouble breathing and in some cases death.

The National Institute of Allergy and Infectious Diseases says one hundred to two hundred people die. It says most of the reactions resulted from peanuts and tree nuts such as walnuts.

People can also be allergic to medicines. The American Academy of Allergy, Asthma and Immunology says about five to ten percent of bad reactions to commonly used medicines are allergic. So, a person's natural defense system overreacts and produces an allergic reaction. The most common reactions include skin rashes, itching, breathing problems and temporary enlargement of areas such as the face.

But the academy estimates that allergic reactions to drugs cause one hundred six thousand deaths each year in the United States alone. It says antibiotics such as penicillin are among the drugs more likely than others to produce allergic reactions. So are anticonvulsants and hormones such as insulin. Other kinds include some anesthesia medicines, vaccines and biotechnology-produced proteins.