The word ‘disease’ means “bad condition” or “a state of being ill”. In the context of medicine, a disease is an abnormal condition of a living organism that is manifested by signs and symptoms. There are several types of diseases. A disease can be classified according to its cause, site, stage of development, treatment, prognosis, etc. The most common type of disease is the communicable disease. The communicable disease is caused by a microorganism that can be transmitted from one person to another. Examples of communicable diseases include measles, chicken pox, influenza, diphtheria, etc. Another type of disease is the noncommunicable disease. It is caused by a nonmicrobial agent and is not transmitted from one person to another directly. Noncommunicable diseases are also known as chronic diseases. Examples of noncommunicable diseases are heart attack, cancer, diabetes, arthritis, etc.
Another classification of diseases is based on the site of origin. The site of origin of a disease refers to the organ or part of the body where the disease starts. Some of the sites of origin of a disease are the skin, the respiratory tract, the digestive tract, the circulatory system, the reproductive system, the urinary tract, the nervous system, the endocrine system, the lymphatic system, the bone marrow, etc. The disease can also start in any other part of the body, which is called systemic disease.
A disease can also be classified according to the stage of development. The stage of development of a disease refers to the stage at which the disease starts. For example, if the disease starts at the early stage of development, it is called acute disease. If the disease starts at the late stage of development, it is referred to as chronic disease.
There are two main categories of treatment for a disease: curative treatment and palliative treatment. Curative treatment is the treatment that cures the disease. Palliative treatment is the treatment that relieves the pain associated with the disease but does not cure the disease itself.
A disease can be classified according to the prognosis. Prognosis is the prediction of the probable outcome of a disease. The outcome of a disease can be good or bad. The good outcome of a disease is when the patient recovers completely from the disease. The bad outcome of a disease is when there is no improvement in the health of the patient after treatment.
