Special Subjects - Merck Manuals Professional Edition

Care of the Surgical Patient

Before elective surgical procedures, whether done in an outpatient or inpatient setting, the surgical team may consult an internist for a formal preoperative evaluation to minimize risk by identifying correctable abnormalities and by determining whether additional perioperative monitoring and treatment are needed. The goal of a thorough preoperative evaluation should be to provide patients with a personalized surgical plan to minimize operative risk and postoperative complications. In some cases, elective procedures should be delayed when possible so that certain underlying disorders (eg, hypertension, diabetes, hematologic abnormalities) can be optimally controlled. In other cases, patients deemed high risk for major surgery may be identified preoperatively as candidates for less invasive interventions.
Chronic Fatigue Syndrome

Chronic fatigue syndrome (CFS, also called myalgic encephalomyelitis/chronic fatigue syndrome [ME/CFS]) is a syndrome of life-altering fatigue lasting > 6 months that is unexplained and is accompanied by a number of associated symptoms. Management includes validating the patient's disability, treating specific symptoms, and in some patients cognitive-behavioral therapy and a graded exercise program.
- Chronic Fatigue Syndrome
Clinical Decision Making

Clinicians must integrate a huge variety of clinical data while facing conflicting pressures to decrease diagnostic uncertainty, risks to patients, and costs. Deciding what information to gather, which tests to order, how to interpret and integrate this information to draw diagnostic conclusions, and which treatments to suggest is known as clinical decision making.
Clinical Trials

Clinical trials are research studies designed to assess the efficacy and safety of an intervention. The intervention is most often a drug but can also be a device, such as a pacemaker or stent, a surgical procedure, or a diagnostic tool, such as a blood test. Clinical trials typically involve patient volunteers, but sometimes they involve healthy subject volunteers. Thousands of clinical trials are conducted each year around the world and may take place at a variety of locations, including universities, hospitals, clinics, physicians’ private offices, and professional clinical research sites. In the beginning of 2021, there were over 374,000 studies registered with ClinicalTrials.gov, a U.S. National Library of Medicine database of privately and publicly funded clinical studies conducted around the world. Several thousand patients or more typically participate in clinical trials for each new drug before it becomes available to the general public.
Dietary Supplements

Dietary supplements are the most commonly used of all integrative, complementary, and alternative therapies, primarily because they are widely available, relatively inexpensive, and can be bought without consulting a health care practitioner.
The Dying Patient

Dying patients can have needs that differ from those of other patients. So that their needs can be met, dying patients must first be identified. Before death, patients tend to follow 1 of 3 general trajectories of functional decline:
- The Dying Patient
- Symptom Relief for the Dying Patient
Exercise

Exercise stimulates tissue change and adaptation (eg, increase in muscle mass and strength, cardiovascular endurance), whereas rest and recovery allow such change and adaptation to occur ( 1). Recovery from exercise is as important as the exercise stimulus. Regular physical activity reduces the likelihood of medical illness, decreases the incidence of the major causes of death, and improves the overall health and quality of life for patients with most medical conditions.
- Overview of Exercise
- Exercise in Older Adults
General Principles of Medical Genetics

A gene, the basic unit of heredity, is a segment of DNA containing all the information necessary to synthesize a polypeptide (protein). Protein synthesis, folding, and tertiary and quaternary structure ultimately determine much of the body’s structure and function.
How to Study in Medical School

The amount of information that must be learned in medical school is so much larger than in college that new study techniques may be required.
- How to Study in Medical School
Idiopathic Environmental Intolerance

Idiopathic environmental intolerance is characterized by recurrent, nonspecific symptoms attributed to low-level exposure to chemically unrelated substances commonly occurring in the environment or sometimes to hypersensitivity to electromagnetic fields. Symptoms are numerous, often involving multiple organ systems, but physical findings are unremarkable. Diagnosis is by exclusion. Treatment is psychologic support and avoidance of perceived triggers, although triggers rarely can be defined.
- Idiopathic Environmental Intolerance
Integrative, Complementary, and Alternative Medicine

Integrative medicine and health (IMH) and complementary and alternative medicine (CAM) include healing approaches and therapies that historically have not been included in conventional, mainstream Western medicine.
Limb Prosthetics

A limb prosthesis is an artificial limb that replaces a missing body part.
Medical Aspects of Travel

Appropriate planning reduces the risks associated with travel, including air travel. Prior to travel, patients and their medical providers should review planned itineraries and relevant medical histories, required vaccinations, prophylactic measures against infections such as malaria and traveler's diarrhea, and advice about personal protection measures, including those related to noninfectious threats. For older travelers, the most common causes of death are heart attack and stroke; for other travelers, the most common cause of death is road traffic crashes.
- Air Travel
- Foreign Travel
Medicolegal Issues

Historically, “incapacity” was considered primarily a clinical finding, and “incompetency” was considered a legal finding. That distinction, at least in terminology, is no longer firmly recognized; most state laws now use “incapacity” rather than “incompetency,” although the terms are frequently used interchangeably. The more useful distinction in health care decision-making terminology now is between .
Nonspecific Symptoms

Fatigue occurs most often as part of a symptom complex, but even when it is the sole or main presenting symptom, fatigue is one of the most common symptoms.
- Fatigue
- Involuntary Weight Loss
Occupational and Environmental Medicine

Occupational and environmental medicine (OEM) focuses on prevention, diagnosis, and treatment of occupation- and environment-related injuries and illnesses. The goal of OEM is to enhance workers' productivity by promoting workers' overall health and safety in the workplace, at home, and in the community.
Principles of Radiologic Imaging

Ionizing radiation (see also Radiation Exposure and Contamination) includes
Recreational Drugs and Intoxicants

Body packing and body stuffing involve swallowing drug-filled packets or placing them in body cavities to evade detection by law enforcement. The risks and consequences vary depending on the amount and type of drug and the way it is packaged.
Rehabilitation

Rehabilitation aims to facilitate recovery from loss of function. Loss may be due to fracture, amputation, stroke or another neurologic disorder, arthritis, cardiac impairment, or prolonged deconditioning (eg, after some disorders and surgical procedures). Rehabilitation may involve
Sexuality

Few elements of the human experience combine physical, intellectual, and emotional aspects as thoroughly as sexuality and all the feelings that go along with it. Accepted norms of sexual behavior and attitudes vary greatly within and among different cultures. Health care practitioners should never be judgmental of sexual behaviors, even under societal pressure. Generally, what is "normal" and "abnormal" cannot be defined medically. However, when sexual behavior or difficulties cause significant distress for a patient or the patient’s partner, or cause harm, treatment is warranted.
- Overview of Sexuality
Tobacco Use

Tobacco use is a major individual and public health problem. Dependence develops rapidly. Major consequences include premature death and morbidity caused by cardiovascular disease, lung and many other types of cancer, COPD (chronic obstructive pulmonary disease), and other disorders. All patients who smoke should be offered smoking cessation interventions.
- Tobacco
- Smoking Cessation