What is the immediate evaluation and management for an adult who is acutely confused, tachycardic (heart rate 111), with otherwise normal vital signs, denies pain, and has a known aortic aneurysm?

Immediate Evaluation and Management of Acute Confusion with Tachycardia and Known Aortic Aneurysm

This patient requires immediate evaluation for acute aortic syndrome (dissection, rupture, or expansion) as the primary cause of altered mental status, with urgent CT angiography as the definitive diagnostic test. 1

Critical Recognition: This is High-Risk Until Proven Otherwise

The combination of acute confusion with tachycardia in a patient with known aortic aneurysm represents a high-risk presentation for acute aortic syndrome (AAS), even without classic chest or back pain. 1

• Altered mental status can be the presenting feature of aortic dissection due to malperfusion of cerebral vessels, hypoperfusion from cardiac tamponade, or impending rupture. 1
• The absence of pain does NOT exclude acute aortic pathology—up to 10% of aortic dissections present without typical pain. 1
• The European Society of Cardiology identifies "focal neurological deficit in conjunction with pain" as a high-risk examination feature, but altered mental status alone warrants urgent evaluation in this context. 1

Immediate Bedside Assessment (First 5 Minutes)

Assess for signs of acute aortic syndrome:

• Check bilateral blood pressures and pulses in all four extremities—a systolic blood pressure difference >20 mmHg between arms indicates dissection involving branch vessels. 1
• Auscultate for new aortic diastolic murmur—indicates acute aortic regurgitation from proximal dissection. 1
• Examine for signs of perfusion deficit—pulse deficits, focal neurological deficits, or signs of limb ischemia. 1
• Assess for hypotension or shock—indicates possible rupture or cardiac tamponade. 1

Simultaneously evaluate for alternative causes of tachycardia and confusion:

• The American Heart Association notes that heart rate 111 bpm is below the 150 bpm threshold where tachycardia itself typically causes instability, suggesting the tachycardia is likely secondary to an underlying condition. 1
• Check oxygen saturation and respiratory status for hypoxemia, which is a common reversible cause of both tachycardia and confusion. 1
• Assess for fever, signs of infection, or dehydration as alternative physiologic stressors. 1

Immediate Diagnostic Workup

Transthoracic echocardiography (TTE) is recommended as the initial imaging investigation and should be performed immediately at bedside. 1

• TTE can rapidly identify pericardial effusion/tamponade, aortic regurgitation, or visible intimal flap in the ascending aorta. 1
• If TTE shows signs of acute aortic dissection (flap, aortic regurgitation, pericardial effusion), refer immediately to surgical team. 1

CT angiography (CTA) is the definitive diagnostic test and must be performed urgently in this unstable patient with suspected AAS. 1

• In unstable patients with suspected AAS, CT or transesophageal echocardiography (TEE) are recommended according to local availability and expertise. 1
• CTA has 93% sensitivity for aortic dissection and provides critical information about the entire aorta, branch vessel involvement, and alternative diagnoses. 1
• The protocol should include non-contrast phase to detect intramural hematoma, followed by contrast injection. 1

Do NOT delay imaging for D-dimer testing in this high-probability patient—the European Society of Cardiology explicitly states that D-dimer testing is not recommended in patients with high probability of aortic dissection. 1

Risk Stratification Using Clinical Features

This patient has at least one high-risk condition (known thoracic aortic aneurysm), which places them in an intermediate-to-high pre-test probability category. 1

High-risk conditions present:

• Known thoracic aortic aneurysm 1

High-risk examination features to assess:

• Evidence of perfusion deficit (pulse deficit, blood pressure difference, focal neurological deficit) 1
• New aortic diastolic murmur 1
• Hypotension or shock 1

The presence of 2-3 groups of risk factors (conditions, pain features, examination features) indicates high probability requiring immediate advanced imaging without D-dimer testing. 1

Immediate Medical Management

While arranging imaging, initiate medical therapy:

• Establish IV access and continuous cardiac monitoring. 1
• Provide supplemental oxygen if oxygen saturation is inadequate or signs of increased work of breathing are present. 1
• If blood pressure is elevated, decrease blood pressure and heart rate—although specific targets have not demonstrated reduction in morbidity and mortality, controlling hemodynamic stress is recommended. 1
• The leading cause of death in aortic dissection is progressive dissection resulting in rupture, which is attributed to pulsatile blood flow and shear forces. 1

Do NOT treat the tachycardia directly with rate-controlling medications—therapy must be directed toward identification and treatment of the underlying cause. 1, 2

Critical Pitfalls to Avoid

• Never assume confusion is unrelated to the aortic aneurysm—altered mental status can result from cerebral malperfusion, hypoperfusion, or impending rupture. 1
• Never delay imaging because the patient denies pain—absence of pain does not exclude acute aortic pathology. 1
• Never discharge this patient without definitive imaging—known aortic aneurysm with new neurological symptoms requires urgent evaluation. 1
• Never attribute tachycardia solely to anxiety or delirium without excluding life-threatening aortic pathology first. 1

Disposition Based on Imaging Results

If acute aortic syndrome is confirmed:

• Type A dissection (involving ascending aorta) requires emergency surgical consultation—mortality is 50% within 48 hours without surgery. 1
• Type B dissection or contained rupture requires urgent vascular surgery or interventional radiology consultation for possible endovascular repair. 1
• Symptomatic aneurysm (expansion causing symptoms) requires repair regardless of diameter. 1

If imaging excludes acute aortic pathology:

• Pursue alternative causes of acute confusion: metabolic derangements, infection, stroke, medication effects, or other neurological emergencies. 1
• The tachycardia is likely a physiologic response to the underlying condition causing confusion. 1