What Are Symptoms? What Are Signs?

In medicine a symptom is generally subjective while a sign is objective. Any objective evidence of a disease, such as blood in the stool, a skin rash, is a sign - it can be recognized by the doctor, nurse, family members and the patient. However, stomachache, lower-back pain, fatigue, for example, can only be detected or sensed by the patient - others only know about it if the patient tells them.

There are varying approaches to defining the medical meanings of signs and symptoms. This article aims to reflect them, rather than judging which the right one is.

The majority of lay people tend to just use the word symptom, and will understand the term 'sign' if used by a doctor as having the same meaning as symptom.

Who notices it defines whether it is a sign or a symptom

Many say it is not necessarily the nature of the sign or symptom, but rather who observers it that defines it.

For example:

• A rash - this could be a sign, symptom, or both.
  
  
  • If the patient notices the rash it is a symptom.
  • If the doctor, nurse or anyone else (but not the patient) notices the rash it is a sign.
  • If both the patient and doctor notice the rash it is both a sign and a symptom.


• Light headache - this can only be a symptom.
  
  
  A light headache can only be a symptom because it is only ever detected by the patient.


• High blood sugar - this can only be a sign
  
  
  High blood sugar can only be a sign because the patient cannot detect it; it can only be measured in a medical laboratory.

It is only a sign when it matters, and a symptom when it doesn't

Historically, patients and physicians used to participate more equally in identifying signs and symptoms during a medical consultation. Over the last 200 years as medicine advanced and diagnosis techniques developed, the identification of signs became more and more the doctor's domain. In fact, in order to listen to the lungs, heart and some other features the patient must keep quiet.

In 1808 the percussion technique was developed - the physician gently tapped the chest wall and listened carefully so that he could diagnose respiratory diseases. Then came the technique of auscultation (using a stethoscope to listen to the circulatory and respiratory body functions), the spirometer (to measure aspects of lung function), the ophthalmoscope (to examine the inside of the eye), the clinical use of X-rays, and the sphygmomanometer (for measuring blood pressure). During the 20th century hundreds of new devices and techniques were created to identify signs - most of them studied by doctors and health care professionals, not patients.

It was during this period in modern medical history that the term symptoms became known as something the patient notices. Many experts say that the meaning of signs has been distorted, and that a sign is anything that really matters, while a symptom remains as a mere observation which did not help in the diagnosis.

Lester S. King, a physician and author of several medical books, wrote:

"The belief that a symptom is a subjective report of the patient, while a sign is something that the physician elicits, is a 20th-century product that contravenes the usage of two thousand years of medicine. In practice, now as always, the physician makes his judgments from the information that he gathers. The modern usage of signs and symptoms emphasizes merely the source of the information, which is not really too important.

Far more important is the use that the information serves. If the data, however derived, lead to some inferences and go beyond themselves, those data are signs. If, however, the data remain as mere observations without interpretation, they are symptoms, regardless of their source. Symptoms become signs when they lead to an interpretation. The distinction between information and inference underlies all medical thinking and should be preserved."

As language constantly changes and evolves it is sometimes necessary to focus on how words and terms are currently being used, rather than how they used to be and therefore should be used. The word symptom(s) is currently used with a wider meaning than "a mere observation", even in medical articles published by scientists. Many years ago the word awful used to mean with awe (awesome).

Medical symptoms

There are three main types of symptoms.

• Chronic symptoms - long lasting or recurrent symptoms. As may be the case with such diseases as diabetes, asthma, or cancer.


• Relapsing symptoms - when a person is affected by symptoms again; symptoms which had occurred in the past, disappeared, and then come back. As may be the case with depression, multiple sclerosis, and also cancer.


• Remitting symptoms - when symptoms improve, and sometimes go away completely.

Symptoms may also progressively get worse, or better. Diseases and conditions can also be described as:

• Asymptomatic diseases/conditions - this means the disease is present but there are no symptoms. For example, during the early stages of breast cancer the patient may feel or sense no symptoms at all. Often, the first a person knows about an asymptomatic disease or condition is during a routine health check. High blood pressure (hypertension) is often asymptomatic.
  
  An asymptomatic infection is also called a subclinical infection. An infected individual may not develop symptoms during the incubation period - also known as the period of subclinical infection. This is often the case with sexually transmitted diseases such as AIDS and genital warts.
  
  The danger of asymptomatic infections is that the infected individual may not experience any symptoms but might transmit the infection to other people. It is also hard for health authorities to know accurately what the incidence of infection is. Examples of asymptomatic infections during which individuals may spread the infection include, whooping cough (pertussis), chlamydia, clostridium difficile, dengue virus, Epstein-Barr virus, Group A streptococcal infection, HIV-1, Legionnaires' disease), measles, gonorrhea, meningitis, tuberculosis (TB), salmonellosis (salmonella infection), noroviruses, poliomyelitis (polio), common cold, pneumonia, and syphilis.
  
  Another danger of asymptomatic (subclinical) infections is that they can cause complications which are unrelated to the infection itself. For example, untreated urinary tract infections may cause premature births.
  
  Many cancers are asymptomatic during their early stages. Prostate cancer, for example, is mainly asymptomatic until it has advanced to a certain point. This is unfortunate, because early treatment is crucial for effective cancer therapy. This is why regular testing for higher risk groups for some cancers is so important.


• Symptomatic diseases/conditions - this means the disease is present and there are symptoms. Some diseases/conditions are always symptomatic, such as motion sickness - feeling nausea and being unwell when travelling by car, plane or boat.


• Constitutional symptoms - also known as general symptoms. These are symptoms which are related to the effects a condition/disease has on the whole body - the systemic effects, e.g. fever, weight loss, or altered appetite. A constitutional symptom relates to the whole body.


• Presenting symptom - also known as chief complaint or presenting complaint, is a term used by doctors which refers to the initial symptom(s) that brought the patient to see the doctor. A patient who is eventually diagnosed with prostate cancer may have first come to the doctor because he had to keep getting up during the night to urinate - the presenting symptom was frequent urination, or getting up at night to urinate.


• Cardinal symptom - this is a term used by medical professionals referring to the symptom that ultimately leads to a diagnosis.

Medical signs

A medical sign is an objective feature indicating some medical fact or characteristic that is detected by a physician, nurse or medical/laboratory device during a physical examination of a patient.

Sometimes a sign may not be noticed by the patient, and have no meaning at all for the patient, but is meaningful for the physician. Signs can help the doctor in his/her diagnosis. Examples of signs include:

• High blood pressure - this may indicate a cardiovascular problem, a reaction to medication, an allergy, as well as many other possible conditions or diseases.


• Clubbing of the fingers - this may point to lung disease, as well as other diseases.

Lester S. King wrote that a sign must have a thing signified. He said a sign must convey information and can only be a sign if it has meaning. He added that "a sign ceases to be a sign when you cannot read it".

There are different types of signs

• Prognostic signs - these are signs that point to the future. Rather than indicating the name of the disease they predict the outcome for the patient - what is likely going to happen to him/her. Hippocrates, a physician in ancient Greece, described the following facial signs as a predictor of impending death (re-written in modern lay terms):
  
  
  Pinched nose, sunken eyes, hollow temples, cold and retracted ears, the skin of the forehead tense and dry, the lips pendent (hanging), relaxed and cold, and a discolored (livid) complexion. (Known as the Hippocratic face. Latin: facies Hippocratica).


• Anamnestic signs - these signs always point to the past. Some skin scars may point to severe acne in the patient's past. An anamnestic sign of polio during childhood may be observed as a limp during adulthood, or a distorted limb.


• Diagnostic signs - these signs help the doctor recognize and identify what the patient has; the name of the condition or disease. For example, elevated levels of PSA (prostate-specific antigen) in a male patient's blood may be a sign of prostate cancer or a prostate problem.


• Pathognominic signs - this is step further from a diagnostic sign - it means "a sure sign". A pathognominic sign is one that leaves the physician certain, sure, without a doubt, that a particular disease is present. For example, thickened lion-like facial skin (leonine facies) is a sure sign (pathognominic sign) of leprosy. A pseudomembrane on the tonsils, pharynx and nasal cavity is a pathognominic sign of diphtheria. A prostate biopsy is when a sample of the prostate is taken and observed under the microscope - if cancerous cells are detected there is no doubt the patient has prostate cancer.