What should I check in an elderly patient presenting with weakness?

Evaluation of Weakness in Elderly Patients

Immediate Vital Sign Assessment and Risk Stratification

Begin by immediately checking vital signs with specific attention to heart rate >90 bpm and systolic blood pressure <110 mmHg, as these thresholds indicate potential hemodynamic instability requiring urgent intervention. 1

• Obtain orthostatic blood pressure measurements (lying, sitting, standing) to detect volume depletion or autonomic dysfunction, which commonly presents as weakness in elderly patients 1
• Perform early blood gas analysis (arterial or venous) for baseline base deficit or lactate assessment, as these are markers of occult hypoperfusion even when vital signs appear stable 2
• Monitor serial base deficit and lactate levels along with vital parameter trends (heart rate, blood pressure, respiratory rate, urinary output) and mental status 2

Essential Laboratory Workup

Order a focused laboratory panel that includes complete blood count, comprehensive metabolic panel (electrolytes, renal function, glucose), and specific nutritional markers. 1

• Check blood glucose and hemoglobin A1c levels, as diabetes causes weakness through neuropathy and metabolic derangement 1
• Obtain phosphate, magnesium, potassium, and thiamine levels before any nutritional intervention, particularly in malnourished patients 1
• Perform urinalysis and urine culture immediately if infection is suspected, as urinary tract infection is extremely common and causes acute mental status changes and weakness in elderly patients 1
• Consider erythrocyte sedimentation rate and C-reactive protein if inflammatory or rheumatologic causes are suspected 1

Comprehensive Medication Review

Review all medications systematically, focusing on myelotoxic agents and sedating medications that are major fall risk factors. 1

• Identify myelotoxic agents including azathioprine, anticoagulants, antibiotics, and antihypertensives 1
• Screen for sedating medications such as psychotropics, which impair emotional and physical drive and contribute to weakness 1, 3
• Assess for polypharmacy effects, as drug-drug interactions and age-related reduction in hepatic and renal clearance commonly cause weakness 2, 1
• Evaluate diuretics causing azotemia and hypokalemia, which frequently present as weakness 3

Focused History Elements

Distinguish true muscle weakness from fatigue, asthenia, or functional decline by determining the pattern: generalized versus focal, proximal versus distal, and acute versus chronic. 1

• Screen for falls in the past 12 months, as falls are frequently unreported and indicate multiple risk factors including medications, balance disorders, and visual deficits 1
• Recognize that elderly patients may present with generalized weakness as the primary manifestation of acute coronary syndrome rather than chest pain 1
• Assess for syncope as a cause of nonaccidental falls, as approximately 30% of older adults presenting with falls may have had syncope, though amnesia commonly obscures the history 2
• Evaluate cognitive impairment, which is frequently present even without formal dementia diagnosis and reduces accuracy of symptom recall 2, 1

Physical Examination Priorities

Perform a gait assessment and "Get Up and Go" test—patients unable to rise from bed, turn, and steadily ambulate require reassessment before discharge. 1

• Conduct a thorough neurological examination to identify focal deficits that would necessitate neuroimaging 1
• Perform fundoscopic examination to look for papilledema indicating elevated intracranial pressure 1
• Assess visual acuity, as visual impairment contributes to falls and functional decline 1
• Examine for peripheral neuropathy in limbs, with common causes in elderly including diabetes mellitus and alcoholism 3

Frailty and Functional Assessment

Assess frailty using the Clinical Frailty Score (1=very fit to 7=very frail) in all elderly patients presenting with weakness. 1

• Evaluate functional status including activities of daily living and instrumental activities of daily living capacity 1
• Recognize characteristics of frailty: weight loss, weakness, exhaustion, reduced physical activity, physical slowing, and cognitive decline 2
• Consider that frailty adds to age-related vulnerability and predisposes to poor outcomes 2, 1

Imaging Considerations

Maintain a low threshold for CT imaging in geriatric patients with weakness, especially if trauma or falls are involved, as the diagnostic yield outweighs risks. 2

• Consider neuroimaging if focal weakness is discovered on examination 4
• Use contrast-enhanced CT when indicated, as benefits outweigh the risk of contrast-induced nephropathy given potential dramatic effects of under-triage 2

Common Pitfalls to Avoid

• Do not dismiss nonspecific complaints as "just weakness"—elderly patients often present atypically with serious conditions like acute coronary syndrome, sepsis, or stroke manifesting only as generalized weakness 1, 5
• Do not overlook medication effects, particularly the cumulative impact of polypharmacy and drug-drug interactions in patients with reduced hepatic and renal clearance 2, 1
• Do not discharge patients who cannot perform the "Get Up and Go" test steadily without further evaluation and reassessment 1
• Do not assume normal vital signs rule out serious pathology—use base deficit and lactate to detect occult hypoperfusion 2