Answer

Very low blood pressure, or hypotension, is generally considered to be a blood pressure reading of less than 90 mmHg systolic (the top number) or less than 60 mmHg diastolic (the bottom number).

However, the definition of hypotension is not solely based on a specific number. It’s also crucial to consider whether the low blood pressure is causing symptoms. Some individuals naturally have blood pressure readings in the 90/60 mmHg range without experiencing any adverse effects. For them, this blood pressure level is normal and not considered hypotension.

Symptoms of Hypotension:

Hypotension becomes a concern when it’s accompanied by symptoms, indicating that vital organs aren’t receiving enough blood flow. Common symptoms include:

• Dizziness or lightheadedness: This is one of the most frequent symptoms.

• Fainting (syncope): This occurs when the brain doesn’t get enough blood.

• Blurry vision: Reduced blood flow can affect vision.

• Nausea: Hypotension can sometimes cause feelings of nausea.

• Fatigue: Low blood pressure can lead to a general feeling of tiredness and weakness.

• Difficulty concentrating: Reduced blood flow to the brain can impair cognitive function.

• Cold, clammy, pale skin: This can indicate reduced blood flow to the extremities.

• Rapid, shallow breathing: The body may try to compensate for low blood pressure by increasing breathing rate.

• Thirst: Sometimes, hypotension can be associated with dehydration.

Types of Hypotension:

Different types of hypotension exist, each with its own causes and characteristics:

• Orthostatic (Postural) Hypotension: This is a sudden drop in blood pressure that occurs when standing up from a sitting or lying position. It’s often caused by dehydration, prolonged bed rest, diabetes, heart problems, or certain medications. Blood pressure typically needs to drop by 20 mmHg systolic or 10 mmHg diastolic within 3 minutes of standing to be classified as orthostatic hypotension.

• Postprandial Hypotension: This is a drop in blood pressure that occurs after eating. It’s more common in older adults and people with high blood pressure or autonomic nervous system disorders. After eating, blood flow increases to the digestive system, and if the body can’t adequately compensate, blood pressure drops elsewhere.

• Neurally Mediated Hypotension (NMH): This type of hypotension is caused by a miscommunication between the heart and the brain. It often occurs after standing for long periods. It’s more common in children and young adults.

• Severe Hypotension related to Shock: This is a life-threatening condition that occurs when blood pressure drops so low that the brain, kidneys, and other vital organs can’t get enough blood. It can be caused by severe blood loss, infection (septic shock), severe allergic reaction (anaphylactic shock), or heart problems. Systolic blood pressure may plummet below 90 mmHg and can be much lower.

Causes of Hypotension:

Numerous factors can contribute to hypotension:

• Dehydration: Insufficient fluid volume reduces blood volume and blood pressure.

• Heart problems: Heart failure, heart valve problems, bradycardia (slow heart rate), and arrhythmias can impair the heart’s ability to pump enough blood.

• Endocrine problems: Hypothyroidism (underactive thyroid), Addison’s disease (adrenal insufficiency), and low blood sugar (hypoglycemia) can lead to low blood pressure.

• Nervous system disorders: Parkinson’s disease and autonomic neuropathy can affect blood pressure regulation.

• Medications: Diuretics (water pills), alpha blockers, beta blockers, ACE inhibitors, calcium channel blockers, tricyclic antidepressants, and medications for Parkinson’s disease or erectile dysfunction can lower blood pressure.

• Severe infection (sepsis): Sepsis can cause vasodilation (widening of blood vessels) and a dangerous drop in blood pressure.

• Severe allergic reaction (anaphylaxis): Anaphylaxis can cause a sudden and severe drop in blood pressure.

• Blood loss: Significant blood loss from injury or internal bleeding reduces blood volume and lowers blood pressure.

• Pregnancy: Blood pressure often decreases during pregnancy, especially during the first 24 weeks.

• Nutritional deficiencies: Lack of vitamin B12 and folate can sometimes contribute to hypotension.

Diagnosis and Treatment:

Diagnosing hypotension involves:

• Medical history and physical exam: The doctor will ask about symptoms, medications, and underlying medical conditions.

• Blood pressure measurements: Blood pressure will be measured in both arms and while lying down, sitting, and standing.

• Blood tests: Blood tests can help identify underlying causes, such as anemia, dehydration, or hormone imbalances.

• Electrocardiogram (ECG or EKG): An ECG can detect heart problems that may be contributing to hypotension.

• Tilt table test: This test is used to diagnose neurally mediated hypotension. The patient lies on a table that is tilted to simulate standing, and blood pressure and heart rate are monitored.

Treatment for hypotension depends on the underlying cause:

• Lifestyle changes: Increasing fluid intake, adding salt to the diet (with doctor’s approval), wearing compression stockings, and avoiding prolonged standing or sitting can help.

• Medications: Fludrocortisone can help the body retain sodium and fluids, which can raise blood pressure. Midodrine can constrict blood vessels, which can also increase blood pressure. Other medications may be used to treat underlying conditions that are causing hypotension.

It is essential to consult a healthcare professional for proper diagnosis and management of hypotension. Self-treating can be dangerous and may mask an underlying medical condition.