A pulse deficit on clinical examination was found in <20% of patients in the IRAD registry and is a poor prognostic sign (Figure 3.1). Pulse deficit was noted more often in patients with type A dissection (p = 0.006).
Blood pressure may increase or decrease:
• Hypertension is more often an initial presentation in type B aortic dissection (70.1% vs. 35.7% in type A, p< 0.001).
• Hypertension may result from a catecholamine surge or underlying essential hypertension. This is a common concomitant finding.
• Hypotension is an ominous finding and should suggest the likelihood of rupture or a leak. Hypotension may be the result of excessive vagal tone, cardiac tamponade, or hypovolemia from rupture of the dissection. Only 4 out of 289 patients with type A aortic dissection in the IRAD registry had an initial systolic blood pressure less than 100 mm Hg.
Neurologic deficits are a presenting sign in up to 20% of cases:
• The most common neurologic findings are syncope and altered mental status.
• Syncope is part of the early course of aortic dissection and may be the result of increased vagal tone, hypovolemia, or dysrhythmia. Syncope was a presenting feature of 12.7% of patients with type A aortic dissection and 4.1% of patients with type B dissection.
• Other causes of syncope or altered mental status include CVAs from compromised blood flow to the brain or spinal cord and ischemia from interruption of blood flow to the spinal arteries.
• Peripheral nerve ischemia can present with numbness and tingling in the extremities. There may be motor symptoms, such as localized weakness of muscles or muscle groups.
• Hoarseness from recurrent laryngeal nerve compression has also been described.
• Horner syndrome is caused by interruption in the cervical sympathetic ganglia and presents with ptosis, miosis, and anhidrosis.
Other signs include the following:
• Superior vena cava syndrome caused by compression of the superior vena cava from a large distorted aorta may occur.
• Findings suggestive of cardiac tamponade (such as muffled heart sounds, hypotension, pulsus paradoxus, jugular venous distension, and Kussmaul sign) must be recognized quickly. These are all ominous and portend a poor prognosis unless intervened on immediately.
• Other diagnostic clues include a new diastolic murmur (seen in 40-50% of patients with proximal dissection), asymmetrical pulses, and asymmetrical blood pressure measurements. Pay careful attention to carotid,
brachial, and femoral pulses on initial exam and look for progression of bruits or development of bruits on reexamination. It is essential to check for pulses bilaterally to help localize the location of the initial tear. Physical findings of a hemothorax may be found if the dissection ruptures into the pleura. However, it is common to find a concomitant left pleural effusion.
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