Special Subjects - Merck Manuals Consumer Version

Chronic Fatigue Syndrome

Chronic fatigue syndrome, also called myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), refers to long-standing severe and disabling fatigue without a proven physical or psychologic cause and without objective abnormalities found on physical examination or laboratory testing.
- Chronic Fatigue Syndrome
Common Imaging Tests

Imaging tests provide a picture of the body’s interior—of the whole body or part of it. Imaging helps doctors diagnose a disorder, determine how severe the disorder is, and monitor people after the disorder is diagnosed. Most imaging tests are painless, relatively safe, and noninvasive (that is, they do not require an incision in the skin or the insertion of an instrument into the body).
Dietary Supplements and Vitamins

Dietary supplements are used by about 75% of Americans. They are the most common therapies included among integrative medicine and health (IMH) and complementary and alternative medicine (CAM), which include healing approaches and therapies that historically have not been included in conventional, mainstream Western medicine. Dietary supplements include medicinal herbs and nutraceuticals (products derived from food sources that claim to provide health benefits). Because the use of dietary supplements is widespread, the United States government passed the Dietary Supplement Health and Education Act (DSHEA) in 1994. It defines a dietary supplement as any product (besides tobacco) that contains a vitamin, mineral, herb or other plant product, or amino acid and that is intended as a supplement to the normal diet. Certain hormones, such as dehydroepiandrosterone (DHEA) and melatonin, also are considered dietary supplements.
Hospital Care

Hospitals provide extensive resources and expertise that enable doctors to rapidly diagnose and treat a wide range of diseases.
Integrative, Complementary, and Alternative Medicine

Integrative medicine and health (IMH) and complementary and alternative medicine (CAM) include a variety of healing approaches and therapies that historically have not been included in conventional Western medicine. Many aspects of CAM are rooted in ancient, indigenous systems of healing, such as those of China, India, Tibet, Africa, and the Americas.
Idiopathic Environmental Intolerance

Idiopathic environmental intolerance involves a wide variety of intermittent symptoms that seem to be triggered by exposure to low levels of several identifiable or unidentifiable substances commonly present in the environment or sometimes to electromagnetic fields.
- Idiopathic Environmental Intolerance
Limb Prosthetics

A limb prosthesis is an artificial limb that replaces a missing body part, usually because it has been amputated.
Medical Decision Making

People and their doctors must make many decisions about medical issues. People must decide whether and when to see a doctor. Doctors and other primary care practitioners (PCPs) must decide what to advise people to do in order to stay well or become well. They both must make decisions about which tests, if any, should be done and which treatment, if any, should be done.
Nonspecific Symptoms

Fatigue is when a person feels a strong need to rest and has so little energy that starting and sustaining activity is difficult. Fatigue is normal after physical exertion, prolonged stress, and sleep deprivation. However, fatigue that increases and develops after activities that previously did not cause it may be one of the symptoms, or, occasionally, the first symptom of a disorder.
- Fatigue
- Involuntary Weight Loss
Occupational and Environmental Medicine

Occupational and environmental medicine (OEM) is the prevention, diagnosis, and treatment of injuries, illnesses, and disabilities that are related to the job and workplace of workers or to the environment of the community. Promoting the overall health and safety of workers in the workplace, at home, and in the community also helps workers be more productive. Doctors who practice OEM may also care for people exposed to environmental contaminants that are not related to work (such as lead poisoning in children).
Recreational Drugs and Intoxicants

To smuggle drugs across borders or other security checkpoints, people may voluntarily swallow packets filled with drugs or hide those packets in body cavities.
The Science of Medicine and Clinical Trials

Doctors have been treating people for many thousands of years. The earliest written description of medical treatment is from ancient Egypt and is over 3,500 years old. Even before that, healers and shamans were likely providing herbal and other remedies to the ill and injured. A few remedies, such as those used for some simple fractures and minor injuries, were effective. However, until recently, many medical treatments did not work and some were actually harmful.
- The Science of Medicine
  - Treatment and recovery: Cause and effect?
  - How Doctors Try to Learn What Works
- What Participants Need to Know About Clinical Trials
Sexuality

Sexuality is the way in which people experience and express the instincts and feelings that make up physical attraction for others. It is a normal part of human experience and is determined by several different factors, including genetic makeup, childhood upbringing, influences of those around us, and societal attitudes. As such, the types of sexual behavior that are considered normal vary greatly within and among different cultures. In fact, defining “normal” sexuality may be impossible.
- Overview of Sexuality
Surgery

Surgery is the term traditionally used to describe procedures (called surgical procedures) that involve manually cutting or stitching tissue to treat diseases, injuries, or deformities. However, advances in surgical techniques have made the definition more complicated. Sometimes lasers, radiation, or other techniques (other than scalpels) are used to cut tissue, and wounds may be closed without stitches.
- Surgery
Tobacco Use

Smoking tobacco is harmful to almost every organ in the body.
- Smoking
- Smoking Cessation
Travel and Health

Travel preparation is crucial, even for healthy people. Proper preparations are inexpensive relative to the costs of getting sick or injured while away from home.