Underground Clinical Vignettes: Pathophysiology, Volume 1: Classic Clinical Cases for USMLE Step 1 Review

HPI-When he first arrives, he shows a declining level of consciousness, becomes pale and short of breath (DYSPNEA), has decreased urine output (OLIGURIA), and is unable to move his left arm and leg; subsequently he faints (SYNCOPE).

PE-VS: marked hypotension (BP 90/50) in left arm, with significantly higher reading in right arm (BP 170/80). PE: pallor; cyanosis; diaphoresis; indistinct heart sounds; aortic regurgitation murmur (high-pitched, blowing, diastolic decrescendo murmur); inspiratory crackles at lung bases bilaterally (due to pulmonary edema); anuria (due to decreased renal perfusion); left-sided hemiplegia.

Labs-ECG: no evidence of myocardial infarct.

Imaging-CT/MR: spiraling intimal flap with true and false lumen (DOUBLE-BARREL AORTA). Angio, aortography: confirmatory. CXR: mediastinal widening (due to hemorrhage).

Gross Pathology-Longitudinal separation of tunica media of aortic wall.

Micro Pathology-N/A

Treatment-ICU monitoring for shock; antihypertensive agents to decrease vascular shear forces (avoid arteriolar dilators such as hydralazine); surgical correction.

Discussion-Aortic dissection is a life-threatening condition requiring immediate treatment. Predisposing factors include hypertension and connective tissue diseases (cystic medial degeneration as in Marfan s syndrome); complications include rupture and extension. Sudden death may occur with pericardial tamponade or extension of dissection into coronary arteries.