What Is Orthostatic Hypotension

Introduction

Orthostatic hypotension may seem like a complex medical term, but it is a peculiar phenomenon that unfolds when you least expect it. One moment, you are comfortably seated or lying down, and suddenly, you decide to stand up. Presto! You find the world is spinning. This condition is not a momentary state; it is a physiological puzzle that impacts countless individuals who scratch their heads in bewilderment. In this comprehensive article, get ready to explore the causes, symptoms, diagnosis, and prevention of Orthostatic Hypotension – where every stand-up act is a surprise waiting to be revealed.

In order to understand this condition, let's break the term into basics.

• Orthostatic: upright position
• Hypotension: low blood pressure 

Combining these two basic terms, Orthostatic hypotension¹ is a sudden low blood pressure condition that happens when you stand up from a comfortably seated or lying position. This condition has another medical term, postural hypotension.³ This condition can happen occasionally or can be chronic. 

Blood pressure² is the measure of force that the heart uses to pump blood through the circulatory system of the body. This is measured in millimetres of mercury (mmHg) and is given as 

• Systolic pressure – the arterial pressure when your heart pushes blood out
• Diastolic pressure – the arterial pressure when your heart rests between beats

Healthy blood pressure is considered to be between 90/60mmHg and 120/80mmHg. 

If your blood pressure drops more than 20mmHg in systolic pressure or 10 mmHg in diastolic pressure within three minutes of standing up you may have orthostatic hypotension.

Causes

Now you may think why does this happen? The physiology behind it is an intricate dance between gravity and our circulatory system. When you're lying or seated, blood easily circulates in the upper and lower parts of the body, but when you stand up, gravity causes blood to pool in the lower body. Our body has a special mechanism to cope with this condition. Special types of cells known as baroreceptors near heart and neck arteries sense this lower blood pressure condition and then send signals to the brain.⁵ Then the brain sends signals to beat faster and pump more blood pressure resulting in even out the blood pressure. Baroreceptors also narrow the blood vessels, helping to increase blood pressure. When something interrupts this normal process of dealing with low blood pressure, it results in blood in your legs having a harder time reaching the upper part of the body. As there's less blood available for the heart to pump to the brain and other parts of the body, blood pressure drops, and this is known as orthostatic hypotension. 

Till here we have unveiled the science of orthostatic hypotension, let's explore the myriad of factors that can throw this delicate balance off-kilter. The following conditions can cause orthostatic hypotension⁶:

• Dehydration: Orthostatic hypotension's symptoms, including dizziness, weakness and fatigue, can be caused by dehydration(the most common culprit)
• Heart problems: Bradycardia(extremely low blood pressure), heart failure, heart attack, and heart valve problems can lead to low blood pressure. These heart conditions slow down the heart's pumping blood when standing up.
• Endocrine problems: Orthostatic hypotension can be caused by Addison's disease(adrenal insufficiency) , hypoglycemia( low blood sugar), thyroid conditions. Also diabetes that damages the nerve cells transmitting signals for controlling blood pressure.
• Nervous system disorders: The ability of the body to control blood pressure can be disrupted by some nervous system disorders like multiple system atrophy, pure autonomic failure(part of the nervous system that automatically controls functions such as breathing, heartbeat, and digestion), Lewy body dementia, Parkinson's disease and amyloidosis.
• Eating meals: Postprandial hypotension ( low blood pressure after eating meals)  occurs commonly in older people.
• Prolonged immobility: Lying down for a long time, like bed rest due to some illness or pregnancy bed rest.

Signs and symptoms

Symptoms and signs of orthostatic hypotension includes:

• Dizziness when standing up
• Confusion
• Weakness
• Fatigue
• Fainting
• Blurry vision 

These are not mere inconveniences; they are signals from the body that something is wrong. Dizziness upon standing after sitting or lying down is the most common symptom of Orthostatic hypotension.

Diagnosis

How do healthcare professionals pinpoint Orthostatic Hypotension amidst a myriad of potential health concerns? Your healthcare provider will measure your blood pressure when you're seated, lying down and standing. Your healthcare provider will diagnose this condition through

• Blood test: To check health conditions like anemia and diabetes 
• Echocardiogram: To check the pumping action of heart
• Electrocardiogram: To check for Heart rhythm
• Exercise stress level: To check heart rate during physical stress

Treatment

Now for the practical part. Armed with a diagnosis, what steps can you take to manage Orthostatic Hypotension? Treatment depends upon the cause of the orthostatic hypotension. Treatment may include:

• Changing, adding, adjusting the dose of medication that causes orthostatic hypotension 
• Drinking more water if you have dehydration and adjusting diet 
• Wearing compression stockings
• Sitting up or standing up with increase frequency each day if you're on bed rest 

Drugs⁴

Mild and severe cases of orthostatic hypotension require additional drug treatment. 

• Midodrine (vasopressor)
• Fludrocortisone (synthetic mineralocorticoid)
• Pyridostigmine (cholinesterase inhibitor)

 In moderate cases, pyridostigmine (Mestinon) is helpful. Fludrocortisone (Florinef) and Midodrine(ProAmatine) are given in more severe cases.

Side effects:

Following are the possible side effects of drug treatment.

• Itching
• Numbness
• Swelling
• Headaches

Complications

Orthostatic Hypotension isn't just about feeling lightheaded or dizzy; it has a ripple effect that can impact various aspects of daily life. People with orthostatic hypotension are at greater risk of 

• Bone fracture (may be caused by falls)
• Postprandial hypotension (after eating high carbonate meal, blood pressure lowers)
• Shock or organ failure (when blood pressure stays too low)
• Supine hypotension( low blood pressure condition that happens when in lying down position)
• Heart diseases (fluctuations in blood pressure can cause different heart problems)

Summary

Orthostatic hypotension is a physiological anomaly that happens when there is a sudden drop in blood pressure when standing up from lying or sitting position. This intricate interplay between gravity and the circulatory system of the body lead to symptoms such as dizziness, fainting and blurred vision. There are various factors that contribute to the orthostatic hypotension, including dehydration, certain medications, and underlying health conditions. Lifestyle modifications such as increased fluid intake and gradual position changes, as well as medications prescribed for symptom control are the practical approaches to control orthostatic hypotension.