The diagnosis of signs and symptoms of the disease has come a long way since Hippocrates tasted the urine of a patient. The identification of signs has become more dependent on the doctor due to the passing of time and the progression of technology.
After the microscope was invented by Antony van Leeuwenhoek in 1674, the possibility of identifying signs of diseases that were invisible to the naked eye open a world of possibilities. The discovery allowed doctors to find foreign organisms in the blood and urine of their patients, notice the changes in blood composition and waste material, and other important signs that were made visible by using the microscope.
The indicators that were seen through the lens of the microscope can be the difference between normal function and dangerous conditions and diseases.
Beginning in the 1800s, medical science has developed at a dizzying pace, which helped physicians clearly identify signs. Many devices are now available to help doctors in the identification and analysis of signs that the patients may not have recognized. The devices include:
- Stethoscope – It is used by doctors to listen to the sounds to the lungs and heart.
- X-ray imaging – This allows doctors to see damages to the bones
- Sphygmomanometer – This is a device that measures blood pressure.
- Spirometer – A device that helps measure lung function.
- Ophthalmoscope – It is used by an eye specialist to examine the inside of the eye.
Hundreds of devices and techniques were created during the 20th century to evaluate signs of diseases. It was during the period of modern medical history that signs and symptoms acquired different meanings.
There are three types of symptoms:
- Remitting symptoms – Symptoms that improve or resolve completely are known as remitting symptoms. The symptoms of the common cold may afflict a person for several days and then suddenly resolves without treatment or medical intervention.
- Chronic symptoms – They are recurrent or long-lasting symptoms. Chronic symptoms are often ongoing conditions, such as asthma, cancer, or diabetes.
- Relapsing symptoms – These are symptoms that might have occurred in the past, resolved, and then returned. Examples are symptoms of depression. They may resolve but could return after a long period.
Some conditions do not show any symptoms at all, such as a high blood person in an individual who may know his condition. Some forms of cancer show no symptoms until reaching the more aggressive stages. These conditions are called asymptomatic conditions. Generally, symptoms refer to abnormal function or discomfort so an asymptomatic condition can be deadly.
Some types of infections do not show symptoms. These are known as subclinical infections and may be contagious even if the person is not aware that he has the infection. The infection may be transmitted to other individuals during its incubation period, or the period when the infectious agent takes hold of the body.
Subclinical infections may cause complications totally unrelated to the infection itself, such as urinary tract infections that when left untreated may cause premature births.