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Causes of secondary hypertension
Secondary hypertension can be caused by a number of health conditions and medications. It is important to identify secondary causes of hypertension because the resulting high blood pressure can often be cured or controlled by eliminating the underlying problem.
Kidney disorders. Kidney disease that progresses to kidney failure almost always results in hypertension owing to the excessive retention of sodium and water in the body. In addition, narrowing of the arteries that supply blood to one or both kidneys, and the resulting reduction in blood flow to the kidneys, causes a form of high blood pressure called renovascular hypertension. In many people, renovascular hypertension can be cured or controlled by surgical repair of the narrowed arteries.
Adrenal tumors. Three types of adrenal tumors can cause hypertension: primary aldosteronism, Cushing's syndrome, and pheochromocytoma. Treatment of primary aldosteronism and Cushing's syndrome is complicated and does not always lower blood pressure. In pheochromocytoma, the tumor secretes large amounts of epinephrine or norepinephrine, which can cause hypertension. Removal of the tumor may cure the hypertension.
Other hormone problems. Over- or underproduction of thyroid hormone (hyperthyroidism or hypothyroidism, respectively), excessive release of growth hormone by a tumor in the pituitary gland, or increased blood calcium levels due to a tumor in the parathyroid gland can all cause hypertension.
Coarctation of the aorta. In this condition, a portion of the aorta narrows, resulting in hypertension in the upper body and low blood pressure in the abdomen and legs. This disorder is the most common cause of secondary hypertension in young people and can be corrected with surgery.
Sleep apnea. People with this disorder stop breathing periodically during sleep. Studies show that people with sleep apnea are more likely to develop hypertension, and the risk rises with the severity of the apnea. Fortunately, treatment of sleep apnea with continuous positive airway pressure, a device that pumps air at high pressure through the nose to keep the airway open, can significantly reduce blood pressure.
Drugs. The following prescription medications can raise blood pressure: corticosteroids such as prednisone (Deltasone and other brands); cyclosporine (Sandimmune, Neoral); tacrolimus (Prograf); epoetin (Epogen and Procrit); and nonsteroidal anti-inflammatory drugs (NSAIDs) such as indomethacin (Indocin) and celecoxib (Celebrex). Some over-the-counter remedies can also elevate blood pressure. These include pain relievers like ibuprofen (Advil, Motrin, and other brands) and naproxen (Aleve), nasal decongestants, and weight loss products containing caffeine. Illegal drugs such as cocaine and amphetamines can increase blood pressure as well.
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