The majority of non-medical people tend to use the words 'sign' and 'symptom' interchangeably. In this article, we will look at what signs and symptoms mean, and the history behind them. We will also explain a little about the different types of signs and symptoms in medicine.
Any objective evidence of a disease, like a skin rash, is a sign and can be recognized by the doctor, family members, and the patient.
However, stomachache, lower-back pain, and fatigue, for example, are symptoms and can only be felt by the patient; they are subjective - others only know about it if the patient tells them.
Contents of this article:
Fast facts on signs and symptoms
Here are some key points about signs and symptoms. More detail and supporting information is in the main article.
- A light headache can only ever be a symptom because no one else can observe it
- Medical symptoms are split into chronic, relapsing, and remitting
- Constitutional symptoms relate to symptoms that affect the whole body
- An example of a medical sign is high blood pressure
The observer defines whether it is a sign or symptom
Some say that it does not matter what the sign or symptom is, what matters is who observes it. For example, a rash could be a sign, symptom, or both:
- If the patient notices the rash, it is a symptom
- If the doctor, nurse, or anyone other than 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
A history of signs and symptoms
A rash can be a sign, a symptom, or both.
Historically, patients and physicians would participate more equally to identify signs and symptoms during a medical consultation. Over the last 200 years, as medicine advanced and diagnosis techniques improved, the identification of signs became more and more dependent on the doctor.
In 1808 the percussion technique was developed - the physician gently taps the chest wall and listens to the sound so that he can diagnose respiratory diseases. Today, percussion of the abdomen is still a useful technique, although chest percussion has been replaced by more accurate methods.
Then came the technique of auscultation (using a stethoscope to listen to the sounds of the heart and lungs), the spirometer (to measure the function of the lungs), 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 evaluate signs - most of them studied by doctors and healthcare professionals, not patients.
It was during this period in modern medical history that the term symptoms became known as something the patient notices.
Some experts say that the meaning of signs has been distorted, and that a sign is anything that is important for diagnosis, and a symptom is just something that is observed which does not help in the diagnosis.
There are three main types of symptoms:
- Chronic symptoms - long lasting or recurrent symptoms. These are often seen in diabetes, asthma, and cancer.
- Relapsing symptoms - symptoms which had occurred in the past, disappeared, and then come back. For instance in depression, multiple sclerosis, and also cancer.
- Remitting symptoms - when symptoms improve, and sometimes go away completely.
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 no symptoms at all. High blood pressure (hypertension) is often asymptomatic.
- Asymptomatic infection - 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 HIV, or HPV, the virus that can cause genital warts or precancer/cancer of the cervix.
The danger of asymptomatic infections is that the infected individual may not experience any symptoms but might transmit the infection to other people.
HIV, HPV (human papilloma virus) HSV, (Herpes simplex virus), Syphilis, Hepatitis B and C are examples of infections that can remain asymptomatic long past their incubation period.
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. For this reason, regular screening tests for individuals at risk are important.
- Symptomatic diseases/conditions - this means the disease is present and so are the symptoms. Some diseases/conditions are always symptomatic, such as motion sickness - feeling nausea and being unwell when traveling in a vehicle.
- Constitutional symptoms - also known as general symptoms, these affect the entire body. They include fever, weight loss, fatigue or altered appetite.
- Presenting symptom - also known as a chief or presenting complaint, presenting symptoms refer 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 visited the doctor because he had to keep getting up at night to urinate. In this case, 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.
A medical sign is an objective feature indicating a medical fact or characteristic that is detected by a physician, nurse, or medical/laboratory device during the examination of a patient.
Sometimes, a sign may not be noticed by the patient, or not seem relevant to them, but it is meaningful for the physician. Below are some examples of specific signs:
- 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 be a sign of lung disease.
Blood pressure is an example of a medical sign.
Doctors are trained to pick up signs that an untrained individual might not see as important.
Signs fit into categories, as follows:
- Prognostic signs - 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 them.
- Anamnestic signs - these signs point to the past. For instance, skin scars may be evidence of severe acne in the patient's past. An anamnestic sign of polio during childhood may be 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.
- Pathognomonic signs - this is one step further from a diagnostic sign - it means "a sure sign." A pathognomonic sign is one that leaves the physician with little doubt that a particular disease is present.