Causes of low blood pressure - Christina Cherry

introduction

Low blood pressure (hypotension) means a blood pressure of below 105/60 mmHg. The normal value of blood pressure is 120/80 mmHg.

A low blood pressure can decrease different causes manifest. Too low blood pressure (hypotension) can be accompanied by certain symptoms (e.g. dizziness with circulatory collapse (syncope), visual disturbances, headache, etc.). It is therefore important for the treating doctor to track down the underlying cause in order to be able to adequately raise the blood pressure.

Causes of hypotension

The causes of low blood pressure can basically be divided into four different categories:

organic causes (e.g. with diseases of the heart or vascular system, the thyroid gland or the adrenal gland) or due to certain environmental conditions (e.g. stress or underweight)
congenital constitutional form low blood pressure (hypotension)
shock situations(e.g. allergic or septic shock)
orthostatic adjustment disorder after the change of position from the lying to the standing position

Hypotension is very common in thin, adolescent women. Physical or mental stress in private or professional environments can also be the cause of low blood pressure. It is not uncommon for low blood pressure to be temporarily caused by a lack of fluid intake or electrolyte imbalance caused. Since hypotension can have very different causes, comprehensive diagnostics should be carried out (examination of the vascular system, imaging of the thyroid gland, collection of venous blood to determine the electrolytes, etc.). In the anamnesis, certain questions should be dealt with, on the basis of which a possible finding of the cause is more likely.

Heart and vascular diseases as the cause of hypotension

Heart disease like Arrhythmia or heart failure can affect heart work and lead to low blood pressure.

Arrhythmia can become one decreased blood output from the heart and thus lead to low blood pressure. This reduced expectoration (cardiac output) mainly occurs circulating excitement at the heart (for example Reentrant tachycardia) or in situations in which the heart is functionally stationary (for example in ventricular fibrillation). Here, less blood volume gets into the central and peripheral arterial vessels per time. Since a continuous supply of oxygen to the sensitive neurons of the brain is essential and this can no longer be guaranteed in such a case, typical symptoms such as Dizziness, syncope, pallor etc. come.

Even with one Heart failure (heart failure) the heart throws less blood out of the main artery (aorta) and the pulmonary trunk. Clinically, this manifests itself in the same way as a reduced blood output as with certain cardiac arrhythmias.

In a so-called Aortic arch syndrome low blood pressure may also occur. Here there is a narrowing (stenosis) just before the exit of the arterial vessels (common carotid artery), which supply the brain. With aortic arch syndrome, the lower extremities are typically still adequately supplied with blood, while the brain is arterially undersupplied. This leads to typical complaints of arterial hypotension.

Venous weakness in the context of hypotension

Vascular diseases such as one Weakness of the vein wall can lead to hypotension. Due to a disruption of the muscular or connective tissue part, it can be too Dilatation of the veins ("varices") to lead. The blood sinks into it and turbulence develops due to the slowed blood flow. The blood stays literally "stand" and sunk. Varices usually appear in the legs, whereupon the blood sinks. This leads to low blood pressure in the central circulation. An undersupply of the arterial vessels of the brain with a possible circulatory collapse can result.

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Disorders of the thyroid and adrenal gland as the cause of hypotension

The thyroid In addition to the adrenal gland, it is one of the organs that is involved in regulating blood pressure by releasing its hormones.

The two hormones are important here Triiodothyronine (T3) and thyroxine (T4), which are formed by the thyroid gland and released into the blood. These hormones act on various cells and tissues and can, among other things, Influence blood pressure. You can increase the heart work (among other things by an increased activity of the sodium / potassium ATPase) and thus also the blood pressure.

At a Underactive thyroid (hypothyroidism), there is a lack of these hormones. Hypothyroidism can result in low blood pressure (hypotension). An autoimmune disease is very common in hypothyroidism (Hashimoto’s thyroiditis, primarily in young women). Therefore, especially in young women with symptoms of low blood pressure (dizziness, listlessness, tiredness, paleness, visual disturbance with star vision), a thyroid-related etiology should be considered.

Addison’s disease

In addition to sex hormones (androgens) in the adrenal cortex mineralocorticoids (especially aldosterone) and glucocorticoids (especially cortisol).

Just Aldosterone and cortisol develop an increase in arterial blood pressure. Hypotension can result in diseases with a hypofunction (for example, Addison’s disease or tumor diseases).

At a Addison’s disease there is one Underactive adrenal cortex. As described above, blood pressure increasing hormones such as aldosterone and cortisol are formed. In the case of a subfunction, these blood pressure-increasing hormone effects are eliminated. As a result, low blood pressure (hypotension) can occur.

Do you have any further questions about an underactive thyroid? Read more about it at: Hypothyroidism

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Stress as the cause of hypotension

At first, the appearance of low blood pressure in stressful situations seems paradoxical. Normally, stressful situations constrict the arterial vessels (vasoconstriction) in order to raise blood pressure while meeting the increased demands on physical exertion.

However, this control circuit fails when long periods of stress occur. The vasoconstriction (vasoconstriction) can no longer be maintained and low blood pressure (hypotension) may develop. Therefore, attention should be paid to the so-called "negative" Stress into one "positive" To transform stress. Stress periods should be limited in total in order to avoid this dysregulation of the vasoconstriction.

Suffer from stress? Read More on the signs of stress on the following page: Symptoms of stress

Adolescence and gender as the cause of hypotension

Also Young age can in principle lead to low blood pressure (hypotension). This is mostly because younger people are very thin in some cases. Especially in adolescence, the body is faced with the challenge of growing quickly. The young people are there (often through "social pressure situations") very thin. Blood pressure is usually lower than in adults.

Up to about 20% of all children up to the age of 15 collapse one or more times due to poor circulation. In the most common cases, one can be traced back orthostatic dysregulation.
Also the so-called vasovagal syncope occurs very often. After getting up, there is a pathological drop in blood pressure and a sagging of the blood in the lower extremities. In this case, the brain is temporarily under-supplied with blood and a circulatory collapse can develop.

The above-described processes of growing up with strong body growth combined with often very low blood pressure occurs increasingly in the female gender. Triggers for low blood pressure (hypotension) can occur in this "stage of life" often also one lack of fluid intake his. The body needs an increased intake of minerals and nutrients for growth.

Lack of fluid as a cause of hypotension

A potentially reversible cause of low blood pressure (hypotension) that can be prevented by simple measures is a lack of fluid intake.

Since about 1.5 to 1.8 liters are lost daily via the urine (additional liquid, for example, through breathing or sweating), the circulating blood volume in the vascular system must be maintained through adequate fluid intake.
The average recommended amount of fluid intake is between 2 to 3 liters can be significantly increased by additional loads (e.g. sports).

Basically, the blood pressure in the vascular system is determined by the mutual interplay hydrostatic pressure (the pressure the blood in the vessel exerts on the vessel wall and potentially wants to push fluid out of the vascular system) and colloid osmotic pressure (Proteins of the blood plasma that hold the fluid in the vascular system).
An imbalance between these two pressures can lead to a change in blood volume and thus in blood pressure. For example, a lack of plasma proteins (especially albumin) leads to water loss in the vascular system and thus to a drop in blood pressure.

In addition, an increased loss of fluid (for example, as a result of injuries with bleeding) can lead to low blood pressure due to fluid loss. Also common Vomiting (vomiting), Diarrhea or increased urination Diabetes mellitus cause increased fluid loss.

Medicines as a cause of hypotension

A sharp drop in blood pressure (hypotension) can in principle also affect the Side effects of medication to be attributed.

For example, diuretic medications such as hypotensive act diuretics (for example the frequently used loop diuretic). Therapy with diuretics should therefore include a regular electrolyte check (especially potassium) and a blood pressure measurement.

In general, it can go through antihypertensive drugs hypotension. Particularly in the early phase of an antihypertensive therapy, severe hypotension can occur. Control measurements of blood pressure should be done regularly here.

Also a few psychotropic have a hypotensive effect. Of particular note here tri- and tetracyclic antidepressants as well as certain antipsychotics from the group of phenothiazines.

Genetic predisposition to cause hypotension

Also investment-related Blood pressure set point disorders in the regulating organs comes as a cause.

This is mainly about the Elongation receptors (baroreceptors) in the carotid sinus of the aorta, to the Medulla oblongata as a circulatory center in the brain stem and around that Kidney as a regulator of volume with the central hormone renin. Blood pressure regulation is a complex unit consisting of several organic systems, which can be brought out of balance by innate effects. A genetically determined setpoint adjustment for the "optimal" blood pressure is in principle possible in both directions. In addition to hypotension, hypertension can also occur due to the system.