What are the causes and treatment options for orthostatic hypotension?

Causes and Treatment of Orthostatic Hypotension

Orthostatic hypotension should be managed first with non-pharmacological approaches, including increased fluid intake, compression garments, and physical counterpressure maneuvers, before considering pharmacological treatments such as fludrocortisone, midodrine, or droxidopa. 1, 2

Definition and Diagnosis

Orthostatic hypotension is characterized by:

• A decrease in systolic blood pressure ≥20 mmHg or diastolic blood pressure ≥10 mmHg within three minutes of standing 2
• Symptoms that develop upon standing and are relieved by sitting or lying down
• Common symptoms: dizziness, lightheadedness, blurred vision, weakness, fatigue
• Less common symptoms: syncope, dyspnea, chest pain, neck and shoulder pain

Common Causes

Neurogenic Causes

• Primary autonomic failure (Parkinson's disease, multiple system atrophy, pure autonomic failure)
• Diabetic autonomic neuropathy
• Non-diabetic autonomic neuropathy
• Dopamine beta-hydroxylase deficiency 3

Non-Neurogenic Causes

• Medications:
  • Antihypertensives (especially vasodilators)
  • Diuretics
  • Antidepressants
  • Alpha-blockers for prostate conditions
  • Sedatives
• Hypovolemia/dehydration
• Cardiac insufficiency
• Venous pooling
• Endocrine disorders (adrenal insufficiency, thyroid dysfunction)
• Vitamin deficiencies (B12)
• Autoimmune disorders
• Paraneoplastic syndromes 2

Treatment Approach

Step 1: Identify and Address Reversible Causes

• Review and modify medications that may cause or worsen orthostatic hypotension
• Correct underlying medical conditions
• Test for orthostatic hypotension before starting or intensifying BP-lowering medication 1

Step 2: Non-Pharmacological Measures (First-Line Treatment)

These are recommended as first-line treatment for orthostatic hypotension, especially in patients with supine hypertension 1, 2:

• Fluid and Salt Intake:

  • Increase fluid intake to 2-3 liters daily
  • Increase salt intake (6-9g daily)

• Physical Countermeasures:

  • Compression garments (thigh-high stockings with 30-40 mmHg pressure)
  • Abdominal binders
  • Physical counterpressure maneuvers (leg crossing, squatting)

• Positional Changes:

  • Elevate head of bed 10° when sleeping (reduces nocturnal diuresis)
  • Avoid sudden position changes
  • Rise slowly from lying to sitting, then to standing

• Daily Habits:

  • Small, frequent meals with reduced simple carbohydrates
  • Avoid alcohol and hot environments
  • Maintain a cool environment
  • Structured exercise program (starting with recumbent exercises)
  • Avoid prolonged standing

Step 3: Pharmacological Treatment

If non-pharmacological measures are insufficient, consider medication 2, 3:

1. Fludrocortisone (0.1mg daily)

   • First-line for neurogenic orthostatic hypotension
   • Effective for suspected hypovolemia
   • Monitor for electrolyte imbalances and supine hypertension

2. Midodrine (5-20mg three times daily)

   • For symptomatic orthostatic hypotension refractory to non-pharmacological measures
   • Last dose should be at least 3-4 hours before bedtime
   • Monitor for supine hypertension

3. Droxidopa (100-600mg three times daily)

   • Indicated for symptomatic neurogenic orthostatic hypotension
   • Take upon arising, at midday, and late afternoon (at least 3 hours before bedtime)
   • Monitor supine blood pressure before and during treatment 3

4. Pyridostigmine (30mg 2-3 times daily)

   • For orthostatic hypotension refractory to other treatments

Special Considerations

• Elderly Patients: More vulnerable due to age-related changes in autonomic function; start with lower medication doses
• Diabetic Patients: Focus on glucose control alongside orthostatic management
• Heart Failure Patients: Use volume-expanding agents cautiously
• Renal Impairment: Start with lower doses of midodrine (2.5mg) and monitor closely 2

Monitoring and Follow-up

• Measure blood pressure in both supine and standing positions
• Monitor for supine hypertension (major risk with all pharmacological treatments)
• Track symptom improvement with a diary
• Regular weight assessment and electrolyte monitoring, particularly with fludrocortisone
• Assess continued effectiveness of treatment periodically 2, 3

Common Pitfalls to Avoid

• Focusing on BP numbers rather than symptom improvement
• Overlooking non-pharmacological measures before starting medications
• Improper timing of medications (administering vasopressors too close to bedtime)
• Inadequate monitoring for supine hypertension
• Failure to switch BP-lowering medications that worsen orthostatic hypotension to alternative therapies 1, 2