Hypotension - Symptoms, Types, Causes & Diagnosis

Hypotension is a drop in systemic blood pressure below an acceptable low level. Pressures below 90/60 are considered to be hypotensive, while there is no agreed standard value for this condition. Hypotension is a relatively...

Introduction

Perfusing vital organs with oxygen-rich blood is only a problem if the pump pressure is insufficient. This leads to symptoms that affect the patient's quality of life. Based on the biometric factors used to measure blood pressure, hypotension is categorized. The absolute value is reached when systolic blood pressure falls to under 90 mm Hg, the relative value is reached when mean arterial pressure falls to under 65 mm Hg, and the absolute value is reached when diastolic blood pressure falls to under 40 mm Hg.

When rising from a seated posture to standing causes a systolic blood pressure drop of more than 20 mmHg or a diastolic drop of more than 10 mmHg, orthostatic hypotension results. It can be severe, defined as drug dependence. In acute conditions, hypotensive shock is a potentially life-threatening condition. Blood pressure is defined as:

Blood pressure is calculated as cardiac output times total peripheral vascular resistance.

The mean arterial pressure (MAP) represents the average blood pressure during the cardiac cycle.

Calculated as follows:

2/3 diastolic plus 1/3 systolic is the average arterial pressure.

Causes

Any of the following medical conditions can lead to low blood pressure:

Pregnancy - Blood vessels dilate rapidly due to changes during pregnancy. This change can lead to a decrease in blood pressure. Throughout the first 24 weeks of pregnancy, low blood pressure is typical. After giving birth, blood pressure usually returns to pre-pregnancy levels.
Diseases of the heart and heart valves - Heart attack, heart failure, valvular heart disease, and an extremely slow heart low blood pressure can result from a slow heartbeat (bradycardia).
Hormone - Related diseases (endocrine diseases); Conditions that affect the parathyroid or adrenal glands, such as addison's illness, which drop in blood pressure. Low blood sugar (low blood sugar) and sometimes diabetes can lower blood pressure.
Dehydration - When the body lacks water, the blood volume (blood volume) in the body decreases. This can lower blood pressure. Fever, severe diarrhoea, heavy use of diuretics, and strenuous exertion can all contribute to dehydration.
Blood loss - In addition to reducing blood volume, excessive blood loss from injuries or internal bleeding also causes a sharp reduction in blood pressure.
Severe infection (sepsis) - Septic shock, a potentially fatal reduction in blood pressure, can result from an infection in the body that has reached the bloodstream.
Severe allergic reactions (anaphylaxis) - One of the telltale indicators of a serious allergic reaction is a sharp drop in blood pressure.
Insufficient amounts - of vitamin B-12, folic acid, and iron can prevent the body from producing enough red blood cells, which can cause anaemia and lower blood pressure. Examination

Blood pressure is regulated by two main mechanisms:

Cardiac output and total peripheral vascular resistance. Pathological conditions that affect one or more of these parameters, therefore, induce hypotension.

The heart functions as a pump system that creates pressure gradients to circulate blood throughout the body. This pumping potential is called the cardiac output. Cardiac output is determined mathematically using the following formula:

Stroke Volume x Heart Rate equals Cardiac Output Disease

It states that decrease stroke volume or heart rate functionally reduces the heart's total cardiac output and thereby its ability to generate blood pressure. Various drugs can also induce hypotension by enhancing these biological parameters. The classes of drugs most famous for lowering heart rate are beta blockers and calcium channel blockers. Diuretics are also a potential cause of decreased cardiac output. Disease states include arrhythmia, valvular insufficiency, valvular stenosis, diastolic or systolic heart failure, massive blood loss and cardiac tamponade.

The body's overall peripheral vascular resistance is the amount of resistance to blood flow through terminal arterioles at different organ locations. This corresponds mathematically to:

The formula for estimating systemic vascular resistance is equal to 80 times the product of cardiac output and mean arterial pressure.

Systemic vascular resistance is calculated as follows: (8 X L x n) / (3.14 x vessel radius4)

Where L is the vessel length and n is the blood viscosity. Functionally, the length of blood vessels in the body does not change and the viscosity does not readily adjust and is accepted as a standard value in most cases. Therefore, the vessel radius is the only modifiable physiological value.

As the arteriole caliber decreases, resistance to blood flow increases, and blood pressure rises. Increasing the diameter of the arteriolar intima, on the other hand, decreases the blood flow resistance, decreasing blood pressure. Autonomic reactions that regulate blood pressure fluctuations are principally responsible for controlling total peripheral vascular resistance The natural state of arteriolar smooth muscle tone relaxes when arterioles dilate.

Thus, lack or attenuation of autonomic nervous system input from drugs or disease states leads to hypotension. Orthostatic hypotension is caused by mild hypovolemia due to autonomic sluggishness and dehydration. Lying down distributes the liquid evenly over your body. However, standing does not adequately increase heart rate and peripheral resistance, resulting in a transient, rapid drop in blood pressure that improves with changes in posture. This is a classic symptom of dizziness and fainting.

In healthy individuals, both cardiac output and total peripheral vascular resistance function as feedback compensatory mechanisms for the other. Decreased cardiac output should increase peripheral resistance by narrowing the arteriolar intima to reduce vessel diameter and maintain blood pressure. Decreased peripheral resistance increases heart rate, increases cardiac output, and maintains blood pressure.

An acute course of life-threatening disease is possible and is classified, depending on etiology, as a distributed shock, cardiogenic shock, hypovolemic shock, obstructive shock, or combined hypotensive shock.

Distributed shock- occurs as an impairment in the ability to maintain total peripheral resistance while preserved cardiac function attempts to compensate. This is typically manifested by extremity and skin heat, edema, increased mucus secretion, and tachycardia. It is traditionally linked to septic shock and anaphylactic allergy responses.
Cardiogenic shock- is the inability to sustain entire peripheral resistance while achieving an acceptable cardiac output. Typically, these patients have cold, dry extremities and bradycardia of the skin.
Hypovolemic shock- is total blood volume loss such that blood pressure cannot be maintained. The total peripheral vascular resistance and cardiac output are both kept constant. This can be caused by trauma with massive blood loss, or by overuse of diuretics with loss of water content in the urine. cause a deficiency. Sheehan syndrome is postpartum pituitary necrolysis in which many pituitary hormones are lost as a result of postpartum shock and bleeding.
Obstructive shock- occurs when the cardiovascular system is blocked, constricted, or compressed, resulting in inefficient blood flow or reduced stroke volume of the heart. Systemically, this leads to a relative decrease in blood pressure. Obstruction may be secondary to pulmonary embolism, tension pneumothorax, cardiac tamponade, constrictive pericarditis, or restrictive cardiomyopathy. They classically present with signs of congestive failure, including dilated jugular veins, peripheral edema, pulmonary crackling, soft heart sounds, or paradoxical pulsations.
Hypotensive shock- can also result from any combination of the above medical conditions occurring simultaneously. One example is Waterhouse-Friederiksen syndrome, inadequate production of mineralocorticoids, glucocorticoids, and sex steroids by the adrenal glands due to frank bleeding into the adrenal glands as a result of bacterial infection with Neisseria. This causes various hypovolemic and distributive shock symptoms.

Types of Hypotension:

Orthostatic hypotension-a rapid reduction in blood pressure when rising from a laying or seated position. One of the causes is dehydration, which can also be brought on by extended bed rest, pregnancy, specific medical conditions, and various drugs. This type of hypotension is common in older people.
Postprandial hypotension- One to two hours following a meal, this drop in blood pressure occurs. It is most likely to affect older people, especially those with autonomic nervous system disorders such as well as Parkinson's illness and excessive blood pressure.
Nerve-mediated hypotension- Standing for long periods of time lowers blood pressure. This type of hypotension primarily affects young adults and children. It might be caused by a breakdown in the heart and brain connection.
Multiple system ateophy - This uncommon condition, also known as Shy-Drager syndrome, affects the nervous system, which regulates involuntary processes like blood pressure, heart rate, breathing, and digestion. Multiple system atrophy with orthostatic hypotension is a combination of this condition. It is related to very high blood pressure while lying down.

Epidemiology

The precise aetiology affects the epidemiology of hypotension, which is highly varied. Those who are older tend to experience symptomatic, non-traumatic hypotensive episodes more frequently. In addition, more physically active and healthier patients have lower asymptomatic resting blood pressure.

Pathophysiology

Blood pressure is constantly regulated by the Autonomic nervous system, It keeps the parasympathetic and sympathetic nerve systems in equilibrium. The sympathetic nervous system speeds up the heartbeat and tightens arteries, which raises blood pressure. By calming arterioles to increase blood vessel diameter and lowering the heart rate, the parasympathetic nervous system reduces blood pressure.

History and Physical

Hypotension is most often asymptomatic. However, when symptoms do occur, the most common are lightheadedness and dizziness. Extremely low pressure can cause fainting. Other symptoms may occur and usually arise from an underlying etiology rather than the hypotension itself. These include chest pain, shortness of breath, irregular heartbeat, fever over 101 degrees Fahrenheit, headache, stiff neck, severe upper back pain, productive cough, diarrhea, vomiting, difficulty urinating, acute allergic reactions, fatigue, or blurred vision.

Evaluation

The evaluation depends on the suspected cause.

Basic laboratory tests can be ordered, including complete blood count (CBC), including differential, thyroid stimulating hormone (TSH), free t4, and cortisol levels. If the patient is in shock, her STAT echocardiography with inferior vena cava (IVC) variability can be performed along with stabilization measures. An echocardiogram determines left ventricular ejection fraction, right ventricular pressure, and the presence or absence of pericardial effusion.

When left ventricular ejection fraction (LVEF) and right ventricular function are adequate and the patient is in distributive shock, inferior vena cava (IVC) variability testing is useful in the management of fluid resuscitation. Pulse pressure variability is used to determine the optimal fluid resuscitation regimen. Saddle-embolic pulmonary embolism can also cause frank hypotension and can be ruled out by chest computed tomography (CT) angiography.

Treatment/Management

No drastic measures should be taken in asymptomatic hypotension. Nonetheless, if symptoms are evident, hypotension treatment should concentrate on curing the underlying cause. Non-invasive imaging or hemodynamic indices of low cardiac output or systemic vascular resistance are not diagnostic but help classify hypotension.

Therefore, electrocardiogram, echocardiogram, and chest x-ray are diagnostic aids. For trauma with hypotension and no apparent blood loss, extended and focused investigation using trauma ultrasonography (e-FAST) may be beneficial to identify the presence of intraluminal hemorrhage. It is important to monitor urine output to ensure that resuscitation efforts with fluids at a rate of 0.5–1.0 mL/kg per hour are adequate.

Along with fluid resuscitation, it is important to monitor electrolytes and replace them if necessary to avoid anomalies. Orthostatic vital signs are also helpful in diagnosis. If a drug is suspected to be the cause, stop that drug. In acute shock, prompt fluid resuscitation with hemostasis is critical. Vasopressors may be indicated if mean arterial pressure is less than 65 mmHg.

Serial blood cultures and early administration of antibiotics are essential if sepsis is suspected. Intramuscular injection of epinephrine is essential if anaphylaxis is suspected. If the patient's vasopressor requirement is steadily increasing and adequate fluid resuscitation is provided, corticosteroids may be used to treat distributive shock. Adding a can also help maintain blood pressure.

Differential Diagnosis

Benign hypotension
Distribution shock
Cardiogenic shock
Hypovolemic shock
Obstructive shock
Combined hypotensive shock

Prognosis

Benign hypotension has an excellent prognosis. The prognosis of symptomatic hypotension depends on etiology and severity.

Complications

Complications of untreated hypotension with reduced cardiac output can be serious and ultimately fatal. If shock or fulminant shock is imminent, untreated hypotension can lead to multiple organ failure. The focus of current recommendations for treating patients with shock or approaching sepsis is aggressive and appropriate fluid resuscitation in order to prevent these effects.

Improve health team

Outcomes

Diagnosis and management of hypotension is best done by a multidisciplinary team of internists, intensivists, endocrinologists, emergency room physicians, and nurses. Outpatients with asymptomatic hypotension do not require treatment.

The goal of treating hypotension should be to reverse the underlying cause, albeit if symptoms are present. Some patients may require vasopressor support in addition to intravenous fluids to reverse hypotension. If the cause is bleeding, a blood transfusion may be needed. Vasopressors may be indicated if mean arterial pressure is less than 65 mmHg.

Serial blood cultures and early administration of antibiotics are essential if sepsis is suspected. Intramuscular injection of epinephrine is essential if anaphylaxis is suspected.

If the patient's vasopressor requirements are steadily increasing, adding steroids to treat distributive shock and adequate fluid resuscitation can also help maintain blood pressure. Outpatient outcomes for asymptomatic hypotension are favorable, but hospital prognosis varies by cause.