Primary versus Secondary Hypertension

By Sarah Samaan, Rosanne Rust, Cynthia Kleckner

Hypertension is easy to diagnose, is often preventable, and can usually be treated successfully. The first step in beating the problem is developing an understanding of what hypertension actually means and what it means to you. Hypertension comes in two types: primary and secondary.

Primary hypertension accounts for 95 percent of cases and is the product of a mishmash of age, genetics, and the things you do (or don’t do) to your body. Although age and genetics are out of your control, in many cases, the simple choices you make every day can both influence your likelihood of developing primary hypertension and affect how well your blood pressure responds to medications. These factors include

  • Being overweight or obese

  • Excessive alcohol use

  • Excessive salt in the diet

  • Inadequate sleep (including sleep apnea)

  • Lack of exercise

  • Not enough fruits and vegetables

  • Smoking

  • Stress

  • Too much fat in the diet, especially animal fats

Several less common but important and correctable causes of hypertension are the result of treatable medical conditions. This type of hypertension is known as secondary hypertension. These conditions account for only 5 percent of hypertension, but it’s important to keep them in mind because after the underlying cause is treated, the blood pressure problem often goes away. These conditions include

  • Coarctation of the aorta: This congenital condition (meaning it’s something you’re born with) means the aorta, the body’s main blood vessel, is pinched in the middle, potentially causing high blood pressure in the upper part of the body and low pressure in the blood vessels feeding the legs.

    It’s usually diagnosed in childhood with an echocardiogram, which is a special ultrasound of the heart and blood vessels. In adults, a CT scan may be necessary.

  • Hyperaldosteronism: This condition causes the adrenal glands (which sit on top of your kidneys) to produce too much of the hormone aldosterone. A blood test showing an unexpectedly low potassium level is a red flag.

  • Medical therapy: Steroids, some decongestants, nonsteroidal anti-inflammatories such as ibuprofen, and birth control pills can raise blood pressure. Though not everyone who takes these medications will have high blood pressure, it makes sense to monitor blood pressure if you’re taking these drugs for extended periods of time.

  • Pheochromocytoma: A rare but important cause of hypertension, this is a tumor that produces adrenaline and other similar chemicals. It can cause severe spikes in blood pressure, headaches, and palpitations. A blood or urine test usually detects this condition.

  • Renal artery stenosis: This ailment refers to a blockage of the arteries that feed your kidneys. If these arteries become blocked, the kidney senses a low blood pressure and sends out signals to the body to raise the blood pressure. The blockage may be due to cholesterol buildup, in which case opening up the artery may not help the blood pressure.

    In younger patients, a rare condition called fibromuscular dysplasia (say that fast three times!) can cause a membrane to form inside the artery, restricting flow. Breaking up the membrane with a balloon on the end of a catheter (a small flexible tube inserted into the artery) often improves blood pressure. An ultrasound or CT scan is ordered when renal artery stenosis is suspected.

  • Supplements: These are well-known blood pressure culprits, especially those marketed for weight loss. Ephedra (also known as ma huang) and bitter orange (also called citrus aurantium) are frequent offenders.

    Because supplements aren’t directly under the oversight of the Food and Drug Administration (FDA), you can’t always be sure what’s in that little pill. Shady supplement dealers have been known to spike their products with steroids and stimulants. If you’re taking a supplement, let your doctor know. Just because it’s “natural” doesn’t mean it’s good for you.

  • Thyroid conditions: These are conditions that affect the thyroid gland, which sits in the middle of the neck. An underactive thyroid (hypothyroidism) tends to raise diastolic blood pressure, whereas an overactive thyroid (hyperthyroidism) raises systolic blood pressure. A simple thyroid blood test usually diagnoses the condition.

When needed, screening tests for secondary hypertension are readily available. Your doctor can go over these options with you and decide whether you need to be tested.