Hypertension, more commonly known as high blood pressure, affects about one-third of American adults, according to the National Heart Lung and Blood Institute. Blood pressure higher than 140/90 is considered hypertension. Although no precise cause is known, most cases of hypertension are related to poor diet, obesity, lack of physical activity or genetics. More rarely, though, high blood pressure may be referred to as secondary hypertension, which means that it develops as the result of another medical condition.
Thyroid Disorders
Several thyroid conditions may cause high blood pressure, and hypertension is often one of many symptoms of the disorders. Among the thyroid diseases that may lead to an elevated blood pressure are Cushing syndrome and adrenal tumors that affect thyroid levels, such as aldosteronism and pheochromocytoma, MedlinePlus reports.
Sleep Apnea
When left untreated, sleep apnea can cause your blood pressure to become high enough to be classified as hypertension. You also are more likely to experience a heart attack or stroke if apnea is not treated properly.
Pregnancy
In rare cases, women may develop high blood pressure when they are pregnant; this is a condition called pregnancy-induced hypertension or pre-eclampsia. If you are pregnant, your risk of developing hypertension is greater if you are older than 35, are carrying multiple babies, have diabetes or kidney disease, are obese or you've have had the condition before, according to The American Congress of Obstetricians and Gynecologists.
Kidney Disease
If your kidneys are not working properly, you may develop hypertension. For example, in the case of kidney cysts, the development of cysts may cause blood pressure to spike, MayoClinic.com reports. If your kidneys cannot filter waste materials efficiently, this also may cause a rise in your blood pressure, because sodium levels are increased.
Complication of Diabetes
Diabetes may also result in hypertension. As with kidney disease, diabetes can cause the kidneys to filter waste improperly, causing blood pressure to elevate.
Coarctation of the Aorta
Coarctation of the aorta is a rare birth defect in which the aorta is abnormally narrow. People who suffer from the defect often develop hypertension, because the heart must work harder than it normally would to pump blood to the rest of the body, MedlinePlus reports.
