A 27-year-old man comes to the emergency department due to acute-onset chest pain and shortness of breath. The pain started suddenly an hour ago while he was lifting a box of books. The patient has no chronic medical conditions, and he was in his usual state of health prior to the onset of symptoms. He does not use tobacco, alcohol, or illicit drugs. Height is 182 cm (71.7 in) and weight is 72 kg (158.7 lb). On physical examination, the patient is in acute respiratory distress. Temperature is 37 C (98.6 F), blood pressure is 90/60 mm Hg, pulse is 120/min and regular, and respirations are 26/min. Pulse oximetry shows 86% saturation on room air. Cardiopulmonary examination reveals pectus excavatum, bilateral pulmonary crackles, and a decrescendo diastolic murmur at the right upper sternal border. The abdomen is soft and nontender. There is no peripheral edema. Subsequently, the patient develops cardiac arrest and dies. Which of the following histologic changes is most likely to be seen on autopsy?

Question

A 27-year-old man comes to the emergency department due to acute-onset chest pain and shortness of breath.  The pain started suddenly an hour ago while he was lifting a box of books.  The patient has no chronic medical conditions, and he was in his usual state of health prior to the onset of symptoms.  He does not use tobacco, alcohol, or illicit drugs.  Height is 182 cm (71.7 in) and weight is 72 kg (158.7 lb).  On physical examination, the patient is in acute respiratory distress.  Temperature is 37 C (98.6 F), blood pressure is 90/60 mm Hg, pulse is 120/min and regular, and respirations are 26/min.  Pulse oximetry shows 86% saturation on room air.  Cardiopulmonary examination reveals pectus excavatum, bilateral pulmonary crackles, and a decrescendo diastolic murmur at the right upper sternal border.  The abdomen is soft and nontender.  There is no peripheral edema.  Subsequently, the patient develops cardiac arrest and dies.  Which of the following histologic changes is most likely to be seen on autopsy?

Quizplus · Accepted Answer

11ec160b_38b7_9750_9249_6535659d9bfd_MD0001_00 This young patient likely had Marfan syndrome complicated by aortic root disease, leading to aortic dissection with acute aortic regurgitation and heart failure. Aortic dissection typically presents with sudden-onset, severe chest or back pain. In Marfan syndrome, the dissection almost always affects the ascending aorta; it can propagate proximally to impair aortic valve closure, causing acute aortic regurgitation (evidenced by a decrescendo diastolic murmur) and heart failure (evidenced by pulmonary edema). Marfan syndrome results from a mutation that disrupts the synthesis, secretion, and incorporation into the extracellular matrix of fibrillin, a protein that provides the glycoprotein scaffolding for elastin structure. Although affected patients are often tall in stature, the syndrome is more reliably recognized by an increased ratio of limb length to trunk length. The most common histologic findings in Marfan-related aortic root disease include fragmentation and loss of the elastic lamellae with fibrosis and cystic medial degeneration (replacement of collagen, elastin, and smooth muscle by a basophilic mucoid extracellular matrix with irregular fiber cross-linkages and cystic collections of mucopolysaccharide). Cystic medial degeneration also occurs with normal aging, but is accelerated in Marfan syndrome. (Choices A and B) Fatty streaking (the early stages of atherosclerosis) is often present in male patients in their 20s, but significant atherosclerotic thickening of the intima is not expected. Coagulative necrosis of the left ventricular wall typically results from atherosclerotic plaque rupture leading to myocardial infarction, which is unlikely in the absence of significant atherosclerotic disease. (Choice D) Myocardial infarction can cause papillary muscle necrosis and rupture. This mechanical complication typically occurs acutely or within 3-5 days of myocardial infarction and leads to acute mitral regurgitation with a holosystolic - rather than diastolic decrescendo - murmur. (Choice E) Inflammation of the vasa vasorum can lead to aortitis and aneurysm formation in syphilis and certain vasculitides (eg, Behçet syndrome). However, such diseases are associated with multiple other manifestations (eg, rash, ulcer, airway disease) and would not explain this patient's pectus excavatum. Educational objective: Marfan syndrome involves a deleterious mutation in fibrillin that mainly affects the structural integrity of the cardiovascular and musculoskeletal systems. Aortic root disease predisposes to aortic dissection, which can present with sudden-onset chest or back pain, acute aortic regurgitation, and heart failure. Common histologic findings in aortic disease include fragmentation and loss of the elastic lamellae with fibrosis and cystic medial degeneration. __________ References: Pathogenesis of aortic wall complications in Marfan syndrome. (http://www.ncbi.nlm.nih.gov/pubmed/29433109)

A 27-Year-Old Man Comes to the Emergency Department Due to Acute-Onset