Top 10 Causes of High Blood Pressure: You Won’t Believe Number 8!

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Have you or a loved one been diagnosed with hypertension or high blood pressure? And if so, did you and your physician talk about the possible causes of the high blood pressure, or did you just start taking medications without really asking questions? Now, the truth of the matter is that most cases of high blood pressure have no clear underlying cause, they have no clear etiology. This is primary or essential hypertension. But about 5 to 10% of the cases of high blood pressure do have an underlying cause, secondary hypertension. Now, if you have high blood pressure and it is actually caused by an underlying condition that could be potentially treatable or reversible, don't you want to know? Today, I'm going to give you 10 causes of high blood pressure.


Facts About Hypertension

Hypertension is the leading cause of heart disease, strokes, and kidney failure. And about 45% of Americans have high blood pressure, and many of them don't quite have it managed well. Most hypertension is due to primary or essential hypertension, meaning that there is no clear cause, no underlying etiology to be identified. But about 5 to 10% of the cases of high blood pressure actually do have an underlying cause or secondary hypertension, and that's what we'll be talking about today.


What Does It Mean To Have High Blood Pressure?

So first, let's define what it means to have high blood pressure or hypertension. Optimal blood pressure is when the systolic blood pressure, that top number, is less than 120, and the diastolic blood pressure, the bottom number, is less than 80. If your systolic blood pressure is greater than or equal to 130, and/or the diastolic blood pressure is greater than or equal to 80, you have hypertension. And that's important to note because the definition of hypertension actually changed in 2017.


Secondary Hypertension: When Should You Be Screened?

So what can you do about it? Well, you definitely want to consult your physician, find out the diagnosis, and if you are a person who has an underlying cause, you want to know that as well. Now, everyone who has high blood pressure does not have to be screened for an underlying cause. But if you have the following characteristics, then you will have a greater chance of having a secondary cause or an underlying cause, and you should be screened.

If you were diagnosed with high blood pressure at a young age, less than 30, and certainly if it's a preadolescent age, you should be screened for secondary causes of hypertension. If you were diagnosed a little bit later in life, like after the age of 45, you had normal blood pressure, then all of a sudden it shot up and it's high, you should be screened.

Also, if you are on many medications and it seems like no matter what, your blood pressure is extremely high, if it's extremely difficult to control, you should be screened. If you have been on a blood pressure regimen that has been working for you quite nicely, but all of a sudden it stops working and your blood pressure shoots up, you should be screened for secondary causes of hypertension.


Causes Of High Blood Pressure

So what are the causes of hypertension other than primary hypertension?

thyroid disease


1.  Thyroid Disease

If you have an abnormal thyroid function, then this could be a cause of hypertension. You could have hyperthyroidism, which is an overactive thyroid, and symptoms include things like a fast heart rate or unintentional weight loss. You can even get a bulging of the eyes (exophthalmos), and you may even have some change in your GI patterns, like you may get frequent stooling. This can happen with hyperthyroidism. Hypothyroidism can also be associated with hypertension, and with hypothyroidism, you have an underactive thyroid or a low functioning thyroid, and symptoms include a slow heart rate and unintentional weight gain. You may even have some edema and fatigue. You can also get a loss of hair or thinning of the eyebrows, especially that tail, the outer eyebrow portion.

2. Obstructive Sleep Apnea

So what are some signs and symptoms of obstructive sleep apnea? If you're a person who snores, or if you have times where you outright snore and then you stop breathing, or you have apnea at night, you could have obstructive sleep apnea. Some symptoms are if you have increased somnolence during the day, or if you're just sleepy in the day all the time.

Also, if you're getting headaches, this could be a symptom of obstructive sleep apnea. Typically patients with obstructive sleep apnea tend to have thick necks, and they may be overweight, but you can also be a thin person and have obstructive sleep apnea. But this is definitely something that can be an underlying cause of high blood pressure.

3. Chronic Kidney Disease

Now I see this quite a bit because I am a board-certified nephrologist in Atlanta. I'm a kidney doctor and a hypertension specialist. And so chronic kidney disease can be an underlying cause of hypertension. And there are several kinds.

  • Diabetic nephropathy associated with diabetes.
  • Glomerulonephritis, like FSG or focal segmental glomerulosclerosis. This is another disease. It causes inflammation in some of your kidney cells and can be associated with hypertension.
  • ADPKD (autosomal dominant polycystic kidney disease) This is a condition where you get many, many abnormal cysts in the kidneys, and it too can be associated with hypertension.
  • Renovascular disease, where you can get atherosclerosis, which causes plaques and a narrowing of the blood flow to the kidneys, a narrowing of the renal arteries, and this also can be associated with hypertension.

4. Cushing's Syndrome

Now, if you have elevated cortisol levels, this most certainly can lead to hypertension. You can have Cushing's syndrome, which means that you have a pituitary tumor that is causing you to make more cortisol, or you can have actually an excess of cortisol hormone coming from your adrenal glands. And your adrenal glands are those triangular glands that sit on top of your kidneys back in the flanks.



Now, if you're making excess cortisol, this can lead to high blood pressure. It can also give you some other signs and symptoms as a bit of a hint that you might have it. So yes, you can have very high blood pressure. You can also develop excess fat, especially in the stomach, or even a round moon face or excess fat can develop on your back, and they call that a buffalo hump. You can also develop excess insulin levels with this high cortisol. Other symptoms of Cushing's syndrome may include muscle weakness.

5. Conn Syndrome

In those same adrenal glands, there is a section that makes something called aldosterone, and aldosterone causes your kidneys to hold on to salt and water, and to get rid of potassium. One of the side effects of having excess aldosterone is high blood pressure, and it tends to be very high and very difficult to control with standard amounts of medications.


causes of high blood pressure


6. Brain Tumor

Yes, a brain tumor can be an underlying cause of hypertension. Let me explain. If you have a brain tumor that's causing increased pressure in your head or increased intracranial pressure, it can lead to high blood pressure. You have to have a certain level of blood pressure in the body in order to perfuse the brain or to give the brain proper blood flow. So if a brain tumor is causing high intracranial pressure, high pressure within the brain, then your blood pressure has to be even higher. And this is something called a Cushing reflex. It's different from Cushing's syndrome that we talked about earlier. So if you have high intracranial pressure from something like a brain tumor, you will get hypertension, you will get a slow heart rate or bradycardia, and you will also have abnormal breathing. Other brain issues that can lead to hypertension include brain bleeds, like a subarachnoid hemorrhage, or even a stroke. Please be sure to watch my YouTube video on "10 High Blood Pressure Symptoms You Should Never Ignore."


7. Coarctation of the Aorta

Now, coarctation of the aorta is actually a congenital heart defect, and it's one of the leading causes of hypertension in children. When you have coarctation of the aorta, you have a narrowing in a part of the aorta, which is that huge artery, it's the body's largest artery, and it comes out of the heart, out of that left ventricle.

When you have this narrowing, you can get symptoms such as hypertension. Specifically, you will have hypertension in the upper body. You might have hypertension in the arms, or headaches from high pressure in the brain. You can also get nosebleeds if you have coarctation of the aorta. And if someone checks your pulse, you might have bounding, very strong pulses, all this in the upper extremities, and then your radial pulses. But in the lower body, you may have diminished or absent pulses.

You also may have claudication or cramping of the legs and relatively thin or decreased muscle in the lower body. So in coarctation of the aorta, you have hypertension, but mainly that hypertension is in the upper body.


pregnancy and high blood pressure


8. Pregnancy

Pregnancy can lead to or worsen hypertension. So if you are a lady who already had hypertension prior to getting pregnant, pregnancy can make it worse. And if you are a lady who had no diagnosis of hypertension, you can get something called preeclampsia during pregnancy. With that preeclampsia, in addition to having high blood pressure, you may even develop some kidney problems, such as protein in the urine, and you may even get some liver dysfunction, but you definitely want to be aware that pregnancy can be an underlying cause of hypertension.

9. Obesity

As you gain weight, as you become more and more obese, the amount of blood flowing through your arteries increases and this can cause increased pressure on your arteries, which can lead to hypertension. You can also get an increased heart rate when you are obese. Being obese is also a risk factor for other underlying causes of hypertension, like diabetes, or it can put you at a higher risk for atherosclerotic disease, which can lead to plaques or blockages in your arteries, which can lead to high blood pressure or even renovascular hypertension.

10. Drugs

Yes, drugs can be an underlying cause of hypertension, either prescription drugs or some illegal drugs. Some of the prescription drugs that can lead to high blood pressure include birth control pills, prednisone, or a steroid that many people take. Even certain transplant medications can lead to hypertension. And then there are certainly illicit drugs that can lead to hypertension, such as cocaine or methamphetamines.



In addition to the 10 causes of high blood pressure I just gave you, there are many more, including pheochromocytoma, or a high sodium diet. In fact, please watch my video on high sodium foods to avoid for more information. To prevent high blood pressure, you definitely want to have a good relationship with your physician, so definitely consult your doctor.

You also want to implement some excellent lifestyle choices like regular exercise and eating healthy foods. Make sure you drink plenty of water and have a low sodium diet. And very importantly, if you are at risk for having a secondary cause, you want to make sure you explore the underlying causes.

Dr. Frita - Frita McRae Fisher, M.D.
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