Introduction
It is common practice to use the words “sign” and “symptom” interchangeably. There is, however, a subtle difference between the two terms; it concerns who is making the observation. Symptoms are subjective qualities that indicate an abnormality or disease. In other words, they are perceived by the affected individual. Examples of symptoms that a patient may describe are an itchy sensation in the skin, headache, joint pain, or nausea.
Signs are objective. They can be noticed by persons other than the affected individual, such as physicians, nurses, and relatives. Examples of outward signs of disease include hyperactivity in a child, forgetfulness in an elderly person, fever, rash, a swollen ankle, or vomiting. Sometimes, signs may not be immediately apparent and further testing may be necessary in order to reveal them. For example, a physician or nurse may check a patient’s blood pressure, blood may be drawn for analysis, or a colonoscopy may be ordered.
Health care professionals use a combination of the signs that they observe and the symptoms described by the patient in order to determine the presence of a particular disorder. This process is called diagnosis. Once a diagnosis has been made, an appropriate course of treatment is evaluated.
Types of Signs and Symptoms
Signs and symptoms come in many different guises, and the way in which they present themselves gives health care professionals further clues as to the nature of the disorder—not only which disease is present but also how severe it is.
Blood pressure, pulse rate, body temperature, and breathing rate are known as vital signs. They are used as standard markers when monitoring an individual’s state of health.
A sign or symptom is described as chronic if it is present for an extended period of time. For example, a chronic cough may be indicative of asthma or a response to an environmental allergen. If a sign or symptom lessens in intensity or disappears, then it is a remitting symptom; conversely, if it worsens or reappears after a period of abatement, then it is relapsing. Some conditions are characterized by these types of signs. Relapsing-remitting multiple sclerosis
is an example. In the relapse stage of this disease, the body’s immune system attacks the sheath of myelin that surrounds nerves in the central nervous system. When the immune response has calmed down, special cells in the central nervous system, called glia, repair the myelin; the remission period is entered.
The presenting symptom is the symptom that first prompts the affected individual to consult a health care professional. If a symptom is general, involving the whole body—such as fatigue, weight loss, or fever—then it is called a constitutional symptom.
A condition that manifests in a tangible way is said to be a symptomatic disease or disorder. An asymptomatic condition, however, can be present without the affected individual being aware of it. Sometimes, routine screening methods such as a mammogram or prostate examination expose the presence of asymptomatic conditions before they become symptomatic, thereby increasing the chance for successful treatment. An asymptomatic infection is an infection by viruses or bacteria that does not result in obvious signs or symptoms. Often, sexually transmitted infections are asymptomatic: Examples include infection by the
Chlamydia trachomatis bacterium (chlamydia) or the Human papillomavirus (HPV). Some infections are asymptomatic while the bacteria or virus is incubating, which is the period of time between exposure to the infectious agent and the onset of symptoms. For example, the incubation period of the seasonal influenza virus is one to four days. Asymptomatic infections can be problematic because it is possible for the affected individual to transmit them to other people unknowingly.
Diseases can have primary and secondary symptoms. Alzheimer’s disease is characterized primarily by symptoms such as memory loss and difficulty with concentration. As a result of the burden caused by these primary symptoms, an affected individual may develop depression. In the case of Alzheimer’s disease, depression is a secondary symptom.
Prognostic signs or symptoms are those that give clues about the future course of the disease. The predicted outcome of the disease is called the prognosis. An example of a disease with an extremely poor prognosis is pancreatic cancer. Pancreatic cancer is rarely diagnosed in its early stages due to lack of symptoms; the chance of successful treatment becomes very low as the disease progresses. Less than 5 percent of pancreatic cancer patients survive for more than five years after diagnosis.
When an addictive substance is abruptly denied to an addicted body, withdrawal symptoms usually become apparent. In alcoholism, these symptoms range from headaches, nausea, and weakness to convulsions and delirium tremens (confusion and visual hallucination). Each addictive substance has a characteristic set of withdrawal symptoms.
Eponymous signs are named after the person who first described them. For example, Braxton Hicks contractions (sometimes known as Hicks sign), prelabor contractions occurring during pregnancy, were first described by John Braxton Hicks.
Perspective and Prospects
Many years ago, physicians could use only their limited powers of observation, along with patients’ description of their symptoms, to make a diagnosis. The development of progressively sophisticated equipment and new methods for clinical testing has made the diagnostic procedure faster and more accurate. As a consequence, treatment is becoming increasingly effective.
A vast amount of medical information is now available to the layperson. Online discussion groups and “symptom checker” Web sites encourage the practice of self-diagnosis. In fact, the act of researching a disease using the Internet as a resource, and subsequently worrying that one is suffering from symptoms of that particular disease, is termed cyberchondria.
Bibliography
Huether, Sue E., and Kathryn L. McCance. Understanding Pathophysiology. 5th ed. St. Louis, Mo.: Elsevier/Mosby, 2012.
Kahan, Scott, Redona Miller, and Ellen Smith. Signs and Symptoms. 2d ed. Philadelphia: Lippincott Williams & Wilkins, 2008.
Knight, Lori. Medical Terminology: An Illustrated Guide. 7th ed. Philadelphia: Lippincott Williams & Wilkins, 2014
Springhouse, ed. Handbook of Signs and Symptoms. 4th ed. Philadelphia: Lippincott Williams & Wilkins, 2009.
Salimpour, Ralph, Pejman Salimpour, and Pedram Salimpour. Photographic Atlas of Pediatric Disorders and Diagnosis. Philadelphia: Lippincott Williams & Wilkins, 2014.
Tierney, Lawrence, and Mark Henderson. The Patient History: Evidence-Based Approach. 2d ed. New York: McGraw-Hill Medical, 2012.
Urden, Linda D., Kathleen M. Stacy, and Mary E. Lough. Critical Care Nursing: Diagnosis and Management. 7th ed. St Louis, Mo.: Elsevier/Mosby, 2014.
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