Primary diseases are diseases that are not related to other diseases, but occur independently in the body and are called primary diseases. A secondary disease is a disease that occurs as a result of a particular disease, and is called a secondary disease, such as primary hypertension and secondary hypertension. Primary hypertension is independent of other diseases and exists in the human body alone, and the cause is often referred to as atherosclerosis, which is a factor in the development of the disease and cannot be described as a disease. Secondary hypertension is most commonly caused by adrenal tumors or increased aldosterone, endocrine disorders, etc. These causes cause the disease and cause an increase in blood pressure, called secondary hypertension. There are primary and secondary epilepsy. Primary epilepsy is called primary epilepsy because no specific foci or previous foci can be found. In secondary epilepsy, the patient has a tumor or metastasis in the cerebral cortex, which causes epilepsy symptoms. This is the difference between primary and secondary epilepsy. One is independent of all diseases, and the other is secondary to a disease that causes another disease called secondary.