September 15, 2019

Hypertensive crisis | Circulatory System and Disease | NCLEX-RN | Khan Academy


– [Voiceover] Usually if
you have hypertension, your blood pressure gets higher and higher over the course of several years even. And this slow rise also
slowly causes complications. But because it’s happening so slowly, there usually aren’t any
symptoms directly caused by high blood pressure. It is possible though that
your blood pressure could rise quickly and severely
enough to be what we call a hypertensive crisis. And actually there are
essentially two categories of hypertensive crises. And the first is hypertensive urgency, and the other is hypertensive emergency. Let’s just go over urgency first. So this hypertensive urgency
is defined as the situation where your blood pressure
is super elevated, but there’s no acute or sudden damage to any of your target
organs like your kidneys, your heart, or your brain. How high are we talkin’ though? Well in general, it’d be
above about 180 millimeters of mercury on the systolic side or above about 110 millimeters of mercury on the diastolic side. So it’s like the blood
pressure goes up super high and really fast, but none
of those target organs get hit, right. But even though these
organs aren’t damaged, there can be symptoms associated
with hypertensive urgency like a severe headache
or shortness of breath, nosebleeds, and severe anxiety. This type of crisis, though,
can usually be managed using some type of oral
antihypertensive medication in an outpatient or a same day sort of observational setting. So urgency means no damage, right. We can probably take a guess as to what hypertensive
emergency is then, huh. An emergency is when
blood pressure is so high that it’s reached levels
that damage target organs. Sometimes this is also referred to as malignant hypertension. During one of these
hypertensive emergencies, systolic blood pressure might increase above 180 millimeters of mercury, while diastolic might be above
120 millimeters of mercury, but it can also happen at
lower pressures in patients whose bodies maybe aren’t as
used to higher blood pressures. Because target organs can be damaged, the consequences of hypertensive emergency are very, very serious and can have severe and permanent effects on the
brain, heart, and kidneys. Some signs and symptoms
of these emergencies can include chest pain,
shortness of breath, back pain, numbness and
weakness, change in vision, and difficulty speaking. One example of a serious
complication that can happen to your head and your brain
is called encephalopathy, where enceph means brain and pathy means disease. And this is when during
a hypertensive emergency, your extremely high
arterial pressure causes your cerebral arterials, which
are like these small arteries in your brain, to lose their
ability to regulate blood flow in the cerebral capillaries, which are even smaller
blood vessels in your brain. As pressure goes up and up,
fluid or blood essentially leaks out into the interstitial
space causing cerebral edema or fluid buildup, which also
causes an increased pressure in the skull and eventually
brain dysfunction. Due to the severity of encephalopathy and other target organ complications, speedy treatment is extremely important, so much so that IV or
intravenous medications are used instead of oral medications, basically to get the
drugs into the bloodstream and working as quickly as possible. An IV vasodilators, IV
calcium channel blocker, or IV beta blocker might be given. Each of these helps the arteries
and the arterials relax. Whichever one is used, the
goal is always the same: to safely reduce the blood
pressure before the pressure causes serious and irreversible
damage to a target organ. Since hypertensive emergency tends to be quite a bit more serious
than hypertensive urgency, it’s usually gonna be managed
in an intensive care unit or other closely-monitored setting.

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