Is a blood pressure of 120/70 mmHg considered hypotension (low blood pressure) in a patient with symptoms of lightheadedness and giddiness?

Blood Pressure of 120/70 mmHg is Not Considered Hypotension Despite Symptoms

A blood pressure of 120/70 mmHg is not considered hypotension, even with symptoms of lightheadedness and giddiness, but represents a relative hypotension for this patient who normally maintains a higher baseline blood pressure. 1

Understanding Blood Pressure Classification

According to the 2024 European Society of Cardiology (ESC) guidelines, blood pressure is categorized as follows:

• Non-elevated BP: <120/70 mmHg
• Elevated BP: 120-139/70-89 mmHg
• Hypertension: ≥140/90 mmHg 1

The patient's reading of 120/70 mmHg falls within the "elevated BP" category, not hypotension. True hypotension is not defined by a specific threshold but is generally considered when systolic BP falls below 90 mmHg.

Relative Hypotension vs. True Hypotension

What this patient is experiencing is "relative hypotension" - symptoms occurring when blood pressure drops from a higher baseline (130/80 mmHg) to a lower level (120/70 mmHg), despite the lower level still being within normal range. This is different from true orthostatic hypotension, which requires:

• A decrease in systolic BP ≥20 mmHg OR
• A decrease in diastolic BP ≥10 mmHg
• Within 3 minutes of standing 2, 3

Why Symptoms Occur Despite "Normal" Blood Pressure

Several mechanisms explain why this patient experiences symptoms at 120/70 mmHg:

1. Cerebral Autoregulation Adaptation: The patient's brain has adapted to functioning at a higher baseline pressure (130/80 mmHg), and may not immediately adjust when pressure decreases.

2. Age Factor: At 60 years, cerebral autoregulation may be less efficient, making the patient more sensitive to BP changes.

3. Medication Effects: If the patient is taking antihypertensive medications, they may be causing symptomatic relative hypotension 1.

Management Approach

1. Evaluate for Orthostatic Changes

• Measure BP and heart rate after 5 minutes lying down and again after 3 minutes standing
• Look for a drop of ≥20 mmHg systolic or ≥10 mmHg diastolic 3

2. Review Medication History

• Identify medications that may cause hypotension (antihypertensives, alpha-blockers for BPH, etc.)
• Consider timing of medications and symptoms 1, 4

3. Non-pharmacological Interventions

• Gradual position changes (sit before standing)
• Adequate hydration
• Compression garments if orthostatic changes are confirmed
• Physical countermaneuvers (leg crossing, muscle tensing) 3, 5

4. Blood Pressure Target Considerations

• For patients with symptomatic relative hypotension, especially those ≥65 years old, the ESC guidelines suggest a more lenient systolic BP target of 130-139 mmHg may be appropriate 1
• In patients with orthostatic symptoms, the goal of therapy should be relief of symptoms rather than achieving a specific BP target 5

Important Caveats

1. Differential Diagnosis: Consider other causes of lightheadedness and giddiness, including:

   • Benign paroxysmal positional vertigo (BPPV)
   • Vestibular disorders
   • Cervical vertigo
   • Neurological conditions 1

2. Special Considerations for Elderly Patients:

   • Overly aggressive BP lowering can lead to orthostatic hypotension, falls, and reduced organ perfusion 4
   • For patients ≥65 years, a target BP of 130-139/80 mmHg may be more appropriate 4

3. Heart Failure Considerations:

   • If the patient has heart failure, symptomatic low BP requires different management approaches 1
   • In heart failure patients, low BP with mild symptoms may not require medication adjustment 1

Remember that while the patient's symptoms are real and concerning, the BP of 120/70 mmHg itself is not classified as hypotension but rather as elevated BP according to current guidelines. The management should focus on addressing the symptoms while maintaining appropriate cardiovascular risk reduction.