Essential (or primary) hypertension is hypertension that has no known cause. Causes may be related to genetics, the enviroment, hormones or how much sodium (salt) you have in your diet. If you have a close family member who has been diagnosed with hypertension there is a greater risk that you will also develop hypertenstion, unless you make the changes needed to prevent it.
Secondary hypertension is hypertension that is caused by another condition or disease. This could be due to conditions like arteriosclerosis, diabetes or kidney disease, or from certain medications. In these cases keeping these other illnesses/conditions under control can help to keep your blood pressure under control.
Medication induced hypertension can be caused either by taking medications or by stopping medications too quickly. Prescription medicaitons that can cause hypertension include: corticosteroids, birth control pills and other hormones, migraine medications, and medications used for chronic anemia (erythropoieten). Many prescription blood pressure medications can cause a rebound hypertension if they are not weaned off slowly. Many over-the-counter medications such as cough/cold medications and medications for asthma can cause hypertension. Street drugs that can cause hypertension include: alcohol, amphetamines, ecstasy (MDMA and derivatives), and cocaine.
Gestational hypertension, caused by pregnany, must be monitored closely for both the mother and fetus's safety. This is one of the reasons your doctor wants to see you more frequently near the end. If you are having high blood pressure during your pregnancy your doctor may recommend you cut salt out of your diet and avoid sodas and processed foods (high in sodium). They may put you on bed rest or delivery the baby early via C-section if your risk is too high. Most often your blood pressure returns to normal after the delivery. A very small percentage of people with hypertension will experience malignant hypertension. This is an extremely high blood pressure that causes swelling of the optic nerve (the nerve that control vision). This is considered a medical emergency. Many of your vital organs are in serious risk of injury including your brain, your eyes, blood vessels, heart, and kidneys.
Hypertensive intracerebral hemorrhage occures when a blood vessel in your brain bleeds due to high blood pressure. The blood accumulates and causes swelling in the brain. Symptoms are usually sudden and vary depending on the extent of damage and where the bleeding is located.