Dear Dr. Donohue: I am a 42-year-old male who has had high blood pressure for the past two years. I have been on many medicines, but my pressure does not go much lower. I do not smoke or drink. No one else in my family has high blood pressure. I am about 25 pounds overweight. My doctor mentioned that I might have secondary high blood pressure. What is that? -- R.B.
Dear R.B.: Ordinary high blood pressure, or hypertension, is essential hypertension -- high blood pressure that comes on its own. Secondary high blood pressure is an elevation of pressure due to another process.
A leading cause of secondary high blood pressure is a narrowed kidney artery. Because of the narrowing, the kidney thinks the body's blood pressure is too low. It begins to turn out large quantities of renin, a kidney-made chemical that raises blood pressure. This kind of high blood pressure is known as renovascular hypertension. It can be cured by relieving the blockage in the kidney artery.
Adrenal gland tumors, Cushing's disease and a very unusual tumor called a pheochromocytoma are other causes of secondary high blood pressure.
The bright side of secondary high blood pressure is its curability when the "secondary" process is treated.
Your young age and the fact that your pressure does not respond to the drugs well are two factors that suggest a secondary process might be going on Even though you did not ask, you can help yourself by losing the extra 25 pounds of weight you carry. Diet and exercise do work. You can also do yourself good by reducing greatly the amount of salt in your diet.
Proof of secondary high blood pressure involves some complicated tests, so do not be surprised if your doctor arranges them for you.