What are the causes of sudden episodes of hypotension (low blood pressure)?

From the Guidelines

Sudden episodes of hypotension require immediate medical attention, and the most recent guidelines recommend calling emergency services or going to the nearest emergency room if you experience sudden drops in blood pressure. While waiting for help, lie down with legs elevated to improve blood flow to the brain. Common causes of hypotension include dehydration, medication side effects, blood loss, severe infection, allergic reactions, or heart problems, as noted in various studies 1.

Causes and Treatment

Treatment depends on the underlying cause but may include intravenous fluids, medication adjustments, or specific treatments for the identified cause. For example, a study published in the European Heart Journal in 2003 1 discusses the management of acute myocardial infarction and mentions cardiogenic shock as a condition characterized by systolic pressure <90 mm Hg and central filling pressure >20 mm Hg. Another study published in the Journal of Allergy and Clinical Immunology in 2020 1 provides guidelines for anaphylaxis management, which can also cause sudden hypotension.

Preventive Measures

Preventive measures include staying well-hydrated, rising slowly from sitting or lying positions, avoiding alcohol, wearing compression stockings, and increasing salt intake if recommended by your doctor. Hypotension becomes dangerous when it reduces blood flow to vital organs, potentially causing dizziness, fainting, confusion, or organ damage. The body normally maintains blood pressure through complex mechanisms involving blood vessel constriction and heart rate adjustments, but these systems can fail due to various medical conditions or medications.

Medication and Management

For recurrent episodes, your doctor might prescribe medications like fludrocortisone (0.1-0.2 mg daily) or midodrine (2.5-10 mg three times daily) to maintain blood pressure, as suggested by guidelines for managing orthostatic hypotension 1. It's crucial to follow the most recent and highest quality guidelines for managing hypotension, considering the patient's specific condition and medical history.

Recent Guidelines

The most recent study from 2020 1 provides updated guidelines for managing anaphylaxis, which can cause sudden hypotension, emphasizing the importance of prompt medical attention and appropriate treatment to prevent morbidity and mortality. Therefore, it is essential to prioritize the most recent and highest quality evidence when managing sudden episodes of hypotension.

From the FDA Drug Label

Hypotension: At lower infusion rates, if hypotension occurs, the infusion rate should be rapidly increased until adequate blood pressure is obtained. If hypotension persists, dopamine HCl should be discontinued and a more potent vasoconstrictor agent such as norepinephrine should be administered. Weaning: When discontinuing the infusion, it may be necessary to gradually decrease the dose of dopamine HCl while expanding blood volume with intravenous fluids. Sudden cessation may result in marked hypotension

Management of Hypotension:

• If hypotension occurs at lower infusion rates, increase the infusion rate until adequate blood pressure is obtained.
• If hypotension persists, discontinue dopamine HCl and administer a more potent vasoconstrictor agent such as norepinephrine.
• When discontinuing the infusion, gradually decrease the dose of dopamine HCl while expanding blood volume with intravenous fluids to avoid marked hypotension 2 2

From the Research

Definition and Diagnosis of Hypotension

• Hypotension can be a sign of significant underlying pathology, and if it is not rapidly identified and addressed, it can contribute to organ injury 3.
• Orthostatic hypotension is traditionally defined as a fall of ≥20 mmHg in systolic and/or ≥10 mmHg in diastolic blood pressure within 3 min of active standing 4.

Causes and Risk Factors of Hypotension

• Heart failure is a common comorbidity among patients with orthostatic hypotension, with a prevalence ranging from 8% to 83% in different populations 4.
• Main predisposing factors for orthostatic hypotension in heart failure patients include HF severity, non-ischemic HF etiology, prolonged bed rest, hypertension, and polypharmacy 4.
• Autonomic failure and neurocardiogenic syncope are also common causes of orthostatic hypotension 5.

Treatment and Management of Hypotension

• Treatment of hypotension is best targeted at the underlying etiology, although this can be difficult to discern early in a patient's disease course 3.
• Non-pharmacologic interventions, such as avoidance of potentially hypotensive medications and use of physical counter maneuvers, are often the first line of treatment 6.
• Pharmacotherapeutic agents, including fludrocortisone, midodrine, and nonsteroidal anti-inflammatory drugs, can be added if non-pharmacologic interventions are inadequate 6.
• The goals of treatment are to improve symptoms and to make the patient as ambulatory as possible, rather than trying to achieve arbitrary blood pressure goals 6.
• Various medications, including midodrine, dihydroergotamine, and ergotamine, have shown efficacy in managing hypotension, but their use must be guided by sound clinical judgment and close follow-up of patients 5, 7.