A 76-year-old man is brought to the emergency department with severe midsternal chest pain and diaphoresis. Past medical history is significant for hypertension, type 2 diabetes mellitus, and asymptomatic right carotid artery stenosis. His blood pressure is 120/70 mm Hg and pulse is 75/min. Lungs are clear on auscultation. ECG shows ST segment elevations greater than 1 mm in leads II, III, and aVF. The patient receives aspirin immediately upon arrival followed by alteplase and a low-dose beta blocker. A single dose of intravenous morphine is given for pain control. Several hours later, the patient is found to be comatose with asymmetric pupils and an irregular breathing pattern. What is the most likely cause of this patient's current condition?

Question

A 76-year-old man is brought to the emergency department with severe midsternal chest pain and diaphoresis.  Past medical history is significant for hypertension, type 2 diabetes mellitus, and asymptomatic right carotid artery stenosis.  His blood pressure is 120/70 mm Hg and pulse is 75/min.  Lungs are clear on auscultation.  ECG shows ST segment elevations greater than 1 mm in leads II, III, and aVF.  The patient receives aspirin immediately upon arrival followed by alteplase and a low-dose beta blocker.  A single dose of intravenous morphine is given for pain control.  Several hours later, the patient is found to be comatose with asymmetric pupils and an irregular breathing pattern.  What is the most likely cause of this patient's current condition?

Quizplus · Accepted Answer

This patient's presentation of chest pain and diaphoresis along with a history of systemic atherosclerosis and type 2 diabetes mellitus is suggestive of acute coronary syndrome. ECG findings are consistent with an inferior ST elevation myocardial infarction (STEMI). Percutaneous coronary intervention (PCI) or fibrinolysis to achieve myocardial reperfusion is recommended for acute MI patients who present within 12 hours of symptom onset. PCI is preferred over fibrinolytic therapy due to lower rates of intracerebral hemorrhage (ICH) and recurrent MI; however, it may not be available at all institutions. In such cases, treatment with fibrinolytics (tenecteplase, alteplase) improves clinical outcomes in the absence of contraindications (eg, gastrointestinal bleeding, recent surgery). Alteplase binds fibrin in the thrombus (clot) and converts entrapped plasminogen to plasmin. Plasmin hydrolyzes key bonds in the fibrin matrix causing clot lysis and restoration of coronary arterial blood flow. The most common adverse effect of fibrinolytic therapy is hemorrhage. This patient has signs of ICH, such as decreased level of consciousness, asymmetric pupils, and irregular breathing. (Choice A) Carotid artery thrombosis can cause an ischemic stroke with fluctuating symptoms that may progress with periods of improvement. Abrupt onset of symptoms along with loss of consciousness after treatment with thrombolytics favors ICH over thrombotic stroke. (Choice B) Aortic dissection typically presents with severe, tearing chest pain that radiates to the interscapular area. It occurs most commonly in patients with hypertension and Marfan/Ehlers-Danlos syndrome. Chest x-ray typically reveals a widened mediastinum. (Choice C) Interventricular septum perforation results in a left-to-right shunt and symptoms of acute heart failure. It presents with chest pain, dyspnea, symptoms of cardiogenic shock, and a harsh holosystolic murmur on the left sternal border. (Choice E) Reperfusion of ischemic myocardium may result in paradoxical cardiomyocyte dysfunction, a phenomenon known as reperfusion injury. This can occur in patients treated with PCI, thrombolytics, or coronary artery bypass grafting. Clinical manifestations include arrhythmias, myocardial stunning (prolonged but reversible contractile dysfunction), and myocyte death. (Choice F) Opioid overdose typically presents with small, constricted pupils (miosis) and respiratory depression (respirations usually <12/min). (Choice G) Pulmonary embolism (PE) presents with acute onset of dyspnea, pleuritic chest pain, and possibly hemoptysis. Tachycardia, hypotension, cyanosis, and loss of consciousness can occur when PE is severe. Educational objective: Fibrinolytic therapy for acute ST segment elevation myocardial infarction is a reasonable reperfusion technique for patients with no contraindications to thrombolysis. Fibrinolytic agents such as alteplase bind to fibrin in the thrombus (clot) and activate plasmin, which leads to thrombolysis. The most common adverse effect of thrombolysis is hemorrhage (eg, gastrointestinal, intracerebral).

A 76-Year-Old Man Is Brought to the Emergency Department with Severe