Secondary hypertension is high blood pressure caused by a specific disease or condition.
All other cases are called essential hypertension. The causes of essential hypertension are not well defined. High blood pressure, if unrecognized or untreated, will eventually lead to the development of heart problems, kidney damage, or a stroke. Often secondary hypertension begins abruptly and the symptoms are severe from the onset. However, most of the time high blood pressure doesn't have obvious symptoms.