Hypertension – causes, symptoms, diagnosis, treatment, pathology
Over a billion around the world have hypertension, or high blood pressure, so that pretty much means it’s pretty common. Let’s start by defining it.
Typically, it’s represented by two numbers: The top number is the systolic blood pressure, which is the arterial pressure when the heart is contracting. The lower number is the diastolic blood pressure, which is the arterial pressure when the heart is relaxing or refilling.
Most of the time, blood pressure is taken in the brachial artery in your upper arm. Because if the pressure is high there, it’s probably high throughout all of the arteries. The guidelines for categorizing blood pressure have recently changed to reflect a growing body of evidence that shows that even moderately high blood pressures can significantly increase your risk for developing heart disease. Now, ‘normal’ systolic blood pressure is defined as less than 120 mmHg, and a normal diastolic pressure is less than 80 mmHg.
Elevated systolic blood pressure is considered between 120 and 129 mmHg and less than 80 mmHg on the diastolic side.
Stage 1 hypertension is between 130 and 139 mmHg on the systolic side, and between 80 and 89 mmHg on the diastolic side.
Stage 2 hypertension is defined as anything that is 140 mmHg or higher on the Systolic side and 90 mmHg or higher on the diastolic side. Typically, both systolic and diastolic pressures tend to climb or fall together, but that’s not always the case.
Sometimes, you can have systolic or diastolic hypertension. One number is normal and the other is really high. This is referred to as isolated systolic hypertension or isolated diastolic hypertension.
High blood pressure is a serious problem for the blood vessels because it causes wear and tear on the endothelial cells that line the inside of the blood vessels. Just like a garden hose that’s always under high pressure, in the long term, blood vessels can develop tiny cracks and tears that can lead to serious problems, like myocardial infarctions, aneurysms, and strokes.
Now, about 90% of the time, hypertension happens without a clearly identifiable underlying reason. We call this primary hypertension, or essential hypertension. In other words, over time, pressure in the arteries begins to silently creep up. And there are a bunch of risk-factors that we’ve identified for primary hypertension. And these include: old-age, obesity, salt-heavy diets, and sedentary lifestyles. With the exception of age, all of these can be improved with lifestyle changes. And those changes can help reduce hypertension. About 10% of the time, though, there is a specific, identifiable underlying condition that is the cause of hypertension; and we call this secondary hypertension.
For example, anything that limits the blood flow to the kidneys. The renal blood flow, can cause hypertension, as well as things like atherosclerosis, vasculitis, or aortic dissection. This is because the kidneys play a super important role in blood pressure regulation. When not enough blood flows to the kidneys, the kidney secretes the hormone renin, which ultimately helps the kidneys retain more water. That water contributes to more blood in the arteries, making them more full, which leads to higher pressures. Other diseases can also cause secondary hypertension. Fibromuscular dysplasia, which affects young women, can cause the walls of the large- and medium-sized arteries to thicken.
If it involves the renal artery and limits blood flowing to the kidneys, it triggers more renin. Another example is a tumor that produces excess aldosterone, which just like renin, leads to fluid retention. Finally, if the blood pressure gets really high really fast, it’s referred to as a hypertensive crisis, and involves a systolic greater than 180 mmHg or a diastolic pressure greater than 120 mmHg.
Hypertensive crisis can be further split into hypertensive urgency and hypertensive emergency. With hypertensive urgency, there hasn’t yet been damage to end organs like the brain, kidneys, heart, and lungs. In hypertensive emergency, there has shown to be evidence of damage to end organs.
So, for symptoms, usually primary hypertension isn’t actually accompanied by any symptoms, which is why it’s sometimes referred to as a “silent killer”.
Secondary hypertension might involve a variety of symptoms associated with the underlying cause. And finally, hypertensive emergency may involve symptoms like confusion, drowsiness, chest pain, and breathlessness.
The first choice for treatment of hypertension is lifestyle changes, like changes to the diet, exercise, and stress reduction techniques. In addition, there are a variety of antihypertensive medications that may be given in some cases as well.
Alright, as a quick recap, hypertension, or high blood pressure, affects over a billion people around the world, and over time is a major risk factor for heart disease and stroke. Stage 1 hypertension is defined as 130 to 139 mmHg for the systolic blood pressure and between 80 to 89 mmHg for the diastolic pressure, while Stage 2 hypertension is defined as greater than 140 mmHg on the systolic side and greater than 90 mmHg on the diastolic side.
Hypertension usually doesn’t cause any symptoms, and the first line of treatment is lifestyle changes..