How is orthostatic hypotension diagnosed and managed?

Diagnosis and Management of Orthostatic Hypotension

Diagnosis

Orthostatic hypotension is diagnosed when there is a decrease in systolic blood pressure ≥20 mmHg or a decrease in diastolic blood pressure ≥10 mmHg within 3 minutes of standing compared to supine position. 1, 2, 3

Diagnostic Procedure:

• Measure blood pressure after 5 minutes of lying supine
• Then measure again after 1 and 3 minutes of standing
• If patient cannot tolerate standing, record the lowest systolic BP during upright posture 4
• If standard orthostatic vital signs are nondiagnostic but clinical suspicion is high, head-up tilt-table testing should be performed 2, 3

Common Symptoms:

• Dizziness, lightheadedness
• Visual disturbances
• Weakness, fatigue
• Nausea, palpitations
• Headache
• Neck and shoulder pain ("coat hanger syndrome")
• Syncope (less common)

Management

Non-Pharmacological Measures (First-Line)

1. Dietary Modifications:

   • Increased salt intake (6-10g daily/1-2 teaspoons) unless contraindicated 1
   • Acute water ingestion (500ml, 30 minutes before meals or anticipated orthostatic stress) 1
   • Small, frequent meals (4-6 per day) with reduced carbohydrate content 1
   • Avoid alcoholic beverages 1

2. Physical Countermeasures:

   • Compression garments (thigh-high compression stockings, abdominal binders) providing 30-40 mmHg of pressure 1
   • Physical counter-pressure maneuvers: leg crossing, squatting, muscle tensing 1
   • Regular exercise of leg and abdominal muscles, especially swimming 1

3. Other Interventions:

   • Sleeping with head of bed elevated to prevent supine hypertension 5
   • Avoiding rapid position changes
   • Avoiding hot environments that cause vasodilation

Pharmacological Treatment (When Non-Pharmacological Measures Are Insufficient)

1. First-Line Medications:

   • Midodrine (5-20mg TID) - Alpha-1 agonist that increases vascular tone

     • Last dose should be taken 3-4 hours before bedtime to avoid supine hypertension 1, 5
     • Monitor for supine hypertension (BP>200 mmHg systolic) 5
     • Contraindicated in patients with severe cardiac disease, acute renal failure, urinary retention 5

   • Fludrocortisone (0.1-0.3mg daily) - Mineralocorticoid that increases sodium retention and plasma volume 1

     • Monitor for hypokalemia, supine hypertension, and edema
     • Use with caution in patients with heart failure or kidney disease

2. Second-Line Medications:

   • Droxidopa (100-600mg TID) - Norepinephrine precursor 1
   • Pyridostigmine (30mg 2-3 times daily) - Acetylcholinesterase inhibitor for refractory cases 1
   • Octreotide - Particularly useful for postprandial hypotension 1

Special Populations

1. Elderly Patients:

   • Higher risk of orthostatic hypotension (20% prevalence) 3
   • More prone to medication side effects
   • Slow titration approach recommended 4
   • Regular monitoring for falls and fractures 4

2. Diabetic Patients:

   • Focus on glucose control in addition to OH management 1
   • Higher risk of autonomic neuropathy

3. Heart Failure Patients:

   • Start beta-blockers and ACE inhibitors/ARBs at very low doses 1
   • Monitor closely for worsening symptoms

4. Pregnant Patients:

   • Volume expansion with IV fluids for acute management
   • Position change to left lateral decubitus position for symptomatic episodes 1

Monitoring and Treatment Efficacy

• Regular blood pressure monitoring in both supine and standing positions 1
• Assess treatment efficacy based on symptom improvement rather than absolute BP values 1
• Monitor for supine hypertension (BP>180/110 mmHg) 1
• For patients on fludrocortisone, monitor serum potassium levels 1
• Regular assessment of treatment efficacy and side effects to adjust treatment 1

Common Pitfalls to Avoid

1. Focusing on BP numbers rather than symptoms 1
2. Overlooking non-pharmacological measures 1
3. Improper timing of medications (e.g., administering vasopressors too close to bedtime) 1
4. Failure to discontinue contributing medications (antihypertensives, antipsychotics, diuretics) 1
5. Inadequate monitoring for supine hypertension 1
6. Misdiagnosing "brittle hypertension" in elderly, leading to inadequate treatment 4

By following this structured approach to diagnosis and management, orthostatic hypotension can be effectively controlled in most patients, improving quality of life and reducing the risk of falls and associated complications.