What are the potential etiologies for altered mental status in an elderly woman with hypertension, without signs of infection or stroke?

Differential Diagnosis for Altered Mental Status in an Elderly Hypertensive Woman

In an elderly hypertensive woman presenting with altered mental status without infection or stroke, you must systematically evaluate metabolic derangements, medication effects, intracranial pathology, cardiac causes, and substance-related issues—with metabolic abnormalities and drug toxicity being the most common culprits in this population.

Priority Life-Threatening Etiologies to Rule Out

Metabolic Derangements

• Hypoglycemia and hyperglycemia are among the most common reversible causes requiring immediate point-of-care testing 1
• Hyponatremia can present with altered mental status and seizures, particularly in patients on antihypertensive medications like ACE inhibitors 2
• Hyperammonemia from hepatic dysfunction, especially in patients with alcohol use 3
• Hypoxia from respiratory causes must be assessed immediately 1
• Hypothermia can precipitate delirium 1

Cardiovascular Causes

• Acute myocardial infarction can present atypically with altered mental status in elderly women without chest pain 1
• Hypertensive emergency with end-organ dysfunction affecting cerebral perfusion 1
• Hypotension and orthostatic changes, particularly in elderly patients on multiple antihypertensives, can cause cerebral hypoperfusion 1, 4

Drug-Related Causes

• Polypharmacy is a major contributor to delirium in the elderly 1
• Anticholinergic medications, sedatives, and narcotics are common precipitants 1
• Drug or alcohol withdrawal must be considered even without obvious intoxication 1
• Antihypertensive medication effects, including severe hyponatremia from ACE inhibitors or excessive blood pressure lowering 2

Intracranial Pathology Despite "No Stroke"

Consider These Even Without Focal Deficits

• Intracranial hemorrhage (ICH) remains possible, as higher systolic blood pressure is significantly associated with abnormal brain imaging in elderly patients with altered mental status 1
• Nonconvulsive seizures require EEG evaluation, not just imaging 1
• Subdural hematoma from unrecognized trauma, especially in elderly patients on anticoagulation
• Wernicke encephalopathy from thiamine deficiency should be considered 1

The yield of neuroimaging in altered mental status is only 11% in meta-analysis of nearly 80,000 patients, but this increases to 16.5% in febrile elderly patients 1. Lower Glasgow Coma Scale, lateralizing signs, and higher systolic blood pressure increase the likelihood of positive findings 1.

Chronic Hypertension-Related Cognitive Changes

Vascular Cognitive Impairment

• Chronic hypertension causes narrowing and sclerosis of small penetrating arteries leading to hypoperfusion, loss of autoregulation, and subcortical white matter demyelination 1, 5
• Subcortical white matter lesions and microinfarcts accumulate over time in poorly controlled hypertension 5
• Mild cognitive impairment (MCI) represents a transitional state where patients show poor recent memory but can still perform daily tasks 1

This is particularly relevant in elderly hypertensive women, who have the highest rates of poorly controlled blood pressure and are at increased risk for stroke and cognitive decline 1.

Systematic Evaluation Approach

Immediate Bedside Assessment

• Fingerstick glucose to rule out hypoglycemia/hyperglycemia 1
• Vital signs including orthostatic measurements in all hypertensive patients over 50 years 1
• Oxygen saturation to assess for hypoxia 1
• Core temperature to identify hypothermia 1

Laboratory Evaluation

• Comprehensive metabolic panel focusing on sodium, glucose, renal function, and calcium 1
• Complete blood count to assess for anemia or infection 1
• Ammonia level if hepatic dysfunction suspected 3
• Thyroid function in elderly patients with new psychiatric symptoms 1
• Toxicology screen including alcohol level, as substance abuse has 92% sensitivity when self-reported but requires objective testing 1

Cardiac Evaluation

• Electrocardiogram to assess for myocardial ischemia, which can present atypically in elderly women 1

Neuroimaging Considerations

• Non-contrast head CT is the initial imaging modality for suspected intracranial pathology 1
• Imaging is usually appropriate when there is suspected intracranial pathology, focal neurologic deficit, lower Glasgow Coma Scale, or significantly elevated blood pressure 1
• History and physical examination have 94% sensitivity for identifying medical conditions causing altered mental status, making selective imaging more appropriate than routine scanning 1

Critical Pitfalls to Avoid

• Do not assume "no stroke" without proper vascular imaging, as small vessel disease and lacunar infarcts may not present with obvious focal deficits 5
• Do not overlook medication reconciliation, as elderly patients often take multiple medications that interact or accumulate 1
• Do not miss orthostatic hypotension by only measuring seated blood pressure—obtain lying and standing measurements 1
• Do not forget non-convulsive seizures, which require EEG rather than imaging for diagnosis 1
• Do not dismiss dehydration, which can significantly worsen cognition and precipitate hypotension, especially with concurrent diuretic use 4

Special Considerations in Elderly Hypertensive Women

Four factors strongly associated with ED delirium are particularly relevant: nursing home residence, cognitive impairment, hearing impairment, and history of stroke 1. Elderly women with hypertension are at particularly high risk for cerebrovascular complications and cognitive decline, with nearly 1 in 3 adult women having hypertension and 1 in 5 deaths being hypertension-related 1.