Examkin

Question

Difficulty: MediumDiagnostic Workup and Test Sequencing

A 58-year-old man is brought to the emergency department by ambulance due to the sudden onset of severe, tearing chest pain that radiates to his interscapular region. The pain began 45 minutes ago. His medical history is notable for essential hypertension, but he admits he has not taken his prescribed amlodipine for the past month. Upon arrival, he appears distressed, pale, and diaphoretic. His temperature is 36.8°C (98.2°F), blood pressure is 82/50 mm Hg, pulse is 124/min, and respirations are 24/min. Pulse oximetry shows 96% on room air. Physical examination reveals markedly distended jugular veins. Cardiac auscultation shows muffled heart sounds and a new early diastolic decrescendo murmur heard best at the right upper sternal border. The lungs are clear to auscultation bilaterally. Pulses in the upper and lower extremities are equal. An electrocardiogram shows sinus tachycardia and low-voltage QRS complexes without acute ST-segment or T-wave abnormalities. A portable chest radiograph demonstrates a widened mediastinum. Which of the following is the most appropriate next step in the diagnostic workup?

  1. Transesophageal echocardiographyAnswer
  2. B
    Computed tomography angiography of the chest
  3. C
    Coronary angiography
  4. D
    Magnetic resonance angiography of the chest
  5. E
    Serum D-dimer assay

Answer

Transesophageal echocardiography is the correct next step in the diagnostic workup.
The correct diagnostic step is transesophageal echocardiography (TEE). This patient's presentation of tearing chest pain radiating to the back, a widened mediastinum, and a new diastolic decrescendo murmur (aortic regurgitation) is classic for an ascending aortic dissection. Crucially, the patient is hemodynamically unstable with signs of cardiac tamponade (hypotension, jugular venous distention, muffled heart sounds, low-voltage QRS), which is a lethal complication of proximal dissections. For suspected aortic dissection, the diagnostic algorithm hinges on hemodynamic stability. In hemodynamically stable patients, computed tomography (CT) angiography is the preferred initial test. However, in hemodynamically unstable patients, transporting them to the CT scanner is contraindicated. Bedside TEE is the imaging modality of choice as it is highly sensitive and specific for ascending aortic dissections, evaluates for pericardial effusion and tamponade, and can be performed without leaving the resuscitation area.

Step-by-Step Solution

1
Analyze the clinical presentation
The patient has sudden, tearing chest pain, a new aortic regurgitation murmur, and a widened mediastinum on chest radiograph.
These findings create a very high pretest probability for an acute thoracic aortic dissection.
2
Assess the patient's hemodynamic status
The patient is in obstructive shock (hypotension, tachycardia) with signs of cardiac tamponade (distended jugular veins, muffled heart sounds, low-voltage QRS).
Aortic dissection can rupture into the pericardial space, causing rapid and life-threatening tamponade. The patient is profoundly unstable.
3
Select the appropriate diagnostic imaging based on stability
Transesophageal echocardiography is selected over computed tomography.
Unstable patients cannot be safely transported to a scanner. A bedside test that provides definitive diagnostic visualization of the aorta and confirms tamponade is required.

Key Concept

Diagnostic sequencing for suspected aortic dissection depends entirely on hemodynamic stability: stable patients receive CT angiography, while unstable patients require bedside transesophageal echocardiography.
Rate this question

Topics

Diagnostic Workup and Test Sequencing

More questions from this topic