What causes disequilibrium when standing, particularly in older adults?

Causes of Disequilibrium When Standing in Older Adults

Disequilibrium when standing in older adults is most commonly caused by orthostatic hypotension, benign paroxysmal positional vertigo (BPPV), medication side effects, vestibular dysfunction, and age-related multisensory deficits—with BPPV being the single most treatable cause that is frequently missed. 1, 2

Primary Causes to Systematically Evaluate

Orthostatic Hypotension (Most Common Cardiovascular Cause)

• Classical orthostatic hypotension is defined as a sustained decrease in systolic BP ≥20 mmHg, diastolic BP ≥10 mmHg, or systolic BP to <90 mmHg within 3 minutes of standing. 1
• Initial orthostatic hypotension causes BP decrease >40 mmHg systolic or >20 mmHg diastolic within 15 seconds of standing, with rapid spontaneous recovery but potential for syncope during the brief hypotensive period. 1
• Delayed orthostatic hypotension occurs beyond 3 minutes of standing with slow progressive BP decrease, particularly common in elderly persons due to stiffer hearts sensitive to preload decrease and impaired compensatory vasoconstrictor reflexes. 1
• Age-related physiological changes predispose to orthostatic symptoms including reduced thirst, impaired sodium/water preservation, diminished baroreceptor response, and reduced heart rate response to orthostatic stress. 2

Benign Paroxysmal Positional Vertigo (Most Common Vestibular Cause)

• BPPV is present in 9% of elderly patients referred for geriatric evaluation, with three-fourths having fallen within the prior 3 months. 1, 2
• In older patients, BPPV frequently presents as unsteadiness or imbalance without classic spinning vertigo sensation, making it easily missed. 3
• Elderly patients with BPPV take longer to seek medical consultation and have lower effectiveness of repositioning maneuvers compared to younger patients. 3
• The Dix-Hallpike maneuver is the gold standard diagnostic test, showing characteristic latency of 5-20 seconds, torsional upbeating nystagmus, and symptoms resolving within 60 seconds. 2

Medication-Induced Disequilibrium (Most Common Reversible Cause)

• Polypharmacy is a major contributor to dizziness in the elderly, particularly with diuretics, β-blockers, calcium antagonists, ACE inhibitors, nitrates, antipsychotics, tricyclic antidepressants, and antihistamines. 2
• Medication review is essential as it represents one of the most common and reversible causes of chronic vestibular syndrome. 4
• Antihypertensives are a leading reversible cause of chronic dizziness and should be systematically reviewed. 5, 4

Vestibular Dysfunction

• Reduced vestibular function is significantly associated with disequilibrium in older adults, with profoundly reduced vestibular function found in approximately 27% of elderly patients with unexplained disequilibrium. 6
• Vestibular function correlates directly with increased sway velocity measured on posturography, even in patients without obvious Romberg sign. 6
• Quantitative measurement of vestibular function should be considered when the cause is not apparent after initial evaluation. 6

Age-Related Multisensory Deficits

• Disequilibrium of unknown cause in older people is associated with brain atrophy, subcortical white matter lesions, and ventricular enlargement on MRI, suggesting small-vessel ischemic disease as a contributing factor. 7
• However, cerebral small vessel disease does not typically cause true vertigo but is associated with chronic imbalance and non-specific dizziness in older adults with vascular risk factors. 5
• Patients with unexplained disequilibrium show increased sway velocity and poorer performance on gait and balance testing compared to age-matched controls. 6

Critical Diagnostic Approach

Initial Assessment Must Include:

• Perform Dix-Hallpike maneuver to diagnose BPPV, as this is the most common and treatable cause in older adults. 1, 2
• Measure orthostatic vital signs at 1 minute and 3 minutes of standing to detect classical, initial, or delayed orthostatic hypotension. 1
• Complete medication review focusing on antihypertensives, sedatives, anticonvulsants, and psychotropic drugs. 2, 4
• Fall risk screening using questions: (1) Have you fallen in the past year? How many times? Were you injured? (2) Do you feel unsteady when standing or walking? (3) Do you worry about falling? 1

Red Flags Requiring Urgent Evaluation:

• Focal neurological deficits suggesting posterior circulation stroke. 1, 2
• Sudden unilateral hearing loss. 2, 4
• New severe headache accompanying dizziness. 4
• Inability to stand or walk. 4
• Downbeating nystagmus or other central nystagmus patterns. 2, 4

Common Pitfalls to Avoid

• Do not assume vague dizziness or imbalance in elderly patients with vascular risk factors is simply "small vessel disease" without first excluding treatable causes like BPPV, medication effects, or orthostatic hypotension. 5
• Do not rely solely on patient's description of symptoms; focus instead on timing, triggers, and associated symptoms to guide physical examination. 2, 4
• Do not assume absence of focal neurologic deficits rules out stroke, as 75-80% of patients with acute vestibular syndrome from posterior circulation infarct have no focal neurologic deficits. 4
• Do not overlook BPPV in elderly patients who describe "unsteadiness" rather than "spinning", as atypical presentations are common in this age group. 3

Impact and Prognosis

• Dizziness increases fall risk 12-fold in elderly patients, with one-third of community-dwelling adults aged >65 years falling annually. 1, 2
• Falls related to dizziness and vertigo account for 13% of all falls in older adults, with estimated costs exceeding $20 billion annually in the United States. 1
• Patients with disequilibrium of unknown cause are four times more likely to fall than age-matched controls over a 5-year period. 7