How to manage a patient experiencing lightheadedness (dizziness) with potential underlying causes such as orthostatic hypotension, and possible contributing factors like antihypertensive or sedative medications?

Management of Lightheadedness

Begin by immediately assessing orthostatic vital signs within 2 minutes of standing to identify orthostatic hypotension (≥20 mmHg systolic or ≥10 mmHg diastolic drop), and critically review all medications—particularly antihypertensives, diuretics, and CNS agents—as these are the most common reversible causes of lightheadedness in clinical practice. 1

Initial Risk Stratification

Age and cardiac history determine your urgency:

• Patients >60 years with cardiovascular disease require high-risk evaluation for cardiac syncope and arrhythmias 1
• Patients <45 years without cardiovascular disease are generally low-risk and likely have reflex-mediated or orthostatic causes 1
• The presence of congestive heart failure on examination indicates higher risk of sudden death and warrants immediate cardiac evaluation 1

Orthostatic Vital Sign Assessment

Measure blood pressure and heart rate supine, then at 1 and 3 minutes after standing:

• Classical orthostatic hypotension: BP drop ≥20/10 mmHg within 3 minutes, with symptoms more important than numeric changes 1, 2
• Initial orthostatic hypotension: BP drop >40 mmHg systolic or >20 mmHg diastolic within 15 seconds of standing, with rapid spontaneous recovery 1
• Delayed orthostatic hypotension: BP drop occurring beyond 3 minutes of standing, common in elderly 1
• POTS (primarily young women): Heart rate increase ≥30 bpm (or ≥40 bpm in ages 12-19) within 10 minutes without significant BP drop 1, 3

Critical pitfall: Up to 40% of asymptomatic patients >70 years have orthostatic hypotension, so correlation with symptoms is essential 1

Medication Review and Management

Immediately identify and address drug-induced causes:

• Antihypertensive agents, diuretics, cardiovascular drugs, and CNS agents are the most frequent culprits 1, 4
• Drug-related syncope is especially common in elderly patients on multiple medications 1
• Alpha-1 blockers, adrenergic blockers, and centrally acting antihypertensives carry highest risk 4
• Discontinue or reduce unnecessary blood pressure-lowering medications when orthostatic hypotension is confirmed 5, 6

Non-Pharmacologic Management (First-Line)

All patients should receive these interventions before considering medications:

• Increase fluid intake to 2-3 liters daily to expand blood volume 3, 2
• Physical counterpressure maneuvers: leg crossing, squatting, or arm tensing when symptoms occur 3, 5, 2
• Avoid standing immediately after meals, especially large meals, due to splanchnic blood pooling 3
• Sleep with head of bed elevated to reduce supine hypertension 6
• Use compression stockings to reduce venous pooling 2

Pharmacologic Management

For patients with persistent symptomatic orthostatic hypotension despite non-pharmacologic measures:

Midodrine (First-Line Pharmacotherapy)

• FDA-approved for symptomatic orthostatic hypotension when lives are considerably impaired despite standard care 6
• Dosing: Start 2.5 mg three times daily (especially if renal impairment), titrate to 10 mg three times daily 6, 7
• Increases standing systolic BP by 15-30 mmHg at 1 hour, with effects lasting 2-3 hours 6, 7
• Last dose must be 3-4 hours before bedtime to minimize supine hypertension 6
• Monitor for supine hypertension (BP >200 mmHg systolic possible); patients should avoid lying flat 6

Fludrocortisone (Alternative or Adjunct)

• Mineralocorticoid that expands blood volume 2
• Can be used alone or with midodrine, but carefully monitor for supine hypertension when combined 6, 2

Pyridostigmine (Alternative)

• Proven beneficial for orthostatic hypotension without causing supine hypertension 2

Critical drug interactions to avoid:

• Do not combine midodrine with MAO inhibitors or linezolid 6
• Avoid concurrent use with other vasoconstrictors (phenylephrine, pseudoephedrine, ephedrine) unless blood pressure closely monitored 6
• Use caution with cardiac glycosides due to bradycardia risk 6

Diagnostic Testing

ECG is warranted when:

• History and physical examination don't reveal etiology 1
• Cardiovascular disease is suspected 1
• Patient is >60 years with cardiac history 1
• A normal ECG has low likelihood of dysrhythmias as cause 1

Laboratory testing has low yield but consider:

• Complete blood count, comprehensive metabolic panel, and thyroid function in adolescents or when anemia/metabolic causes suspected 8
• Renal and hepatic function before initiating midodrine 6

Advanced testing:

• Tilt-table testing if active standing test inconclusive but symptoms strongly suggest orthostatic intolerance 8
• 24-hour Holter monitoring if arrhythmia suspected 8

Special Populations

Elderly patients:

• Higher prevalence of asymptomatic orthostatic hypotension 1
• More susceptible to polypharmacy-induced orthostatic hypotension 1, 4
• Delayed orthostatic hypotension more common due to impaired compensatory reflexes 1

Adolescents with chronic symptoms:

• Consider POTS, especially in young women with fatigue, palpitations, and orthostatic intolerance 1, 8
• Frequently associated with recent infections, chronic fatigue syndrome, and joint hypermobility 1

Follow-Up and Monitoring

Reassess in 2-4 weeks after initiating treatment:

• Document frequency of symptomatic episodes 5
• Verify orthostatic vital signs to assess treatment response 5
• Monitor for supine hypertension if on midodrine 6
• Continue midodrine only if patients report significant symptomatic improvement 6