每日一题_2022.07.29

A 35-year-old, previously healthy man is evaluted in the emergency department for worsening dyspnea. He says that his shortness of breath started during the past week and is getting worse. He denies(否认) chest pain or leg swelling but reports subjective fevers and chills（寒战）. He is admitted to the medical floor for presumed pneumonia（疑似肺炎） and started on antibiotics based on his low-grade fever, tachycardia, oxygen requirement, and chest radiograph showing diffuse interstitial disease and mild pulmonary edema. During the next 12 hours his symptoms worsen, and he is transferred to the ICU for agitation, worsening dyspnea, and hypotension unresponsive to IV fluids. Vitals signs are: temperature 39°C (102.2°F), heart rate 128 beats/min, blood pressure 85/60 mm Hg, respiratory rate 24 breaths/min, oxygen saturation 93% on nonrebreather mask. Physical examination is notable for faint diastolic murmur, bilateral lung crackles, and track marks on the left forearm. Laboratory analysis is notable for white blood cell count of 23,000/μL, creatinine 1.8 mmol/L, lactate 4 mmol/L, and troponin of 1.04 ng/ml. ECG shows sinus tachycardia. Blood cultures are positive for methicillin- resistant Staphylococcus aureus.

Which of the following is the best next step in management?

A. Broaden antibiotics and give 2 liters IV normal saline for hypotension and lactic acidosis.

B. Broaden antibiotics, obtain immediate echocardiography, consult cardiac surgery, and institute appropriate medical management.

C. Call cardiology for catheterization laboratory activation and placement of intra- aortic balloon pump.

D. Broaden antibiotics, obtain immediate echocardiography, institute appropriate medical management, and consult cardiac surgery when blood cultures clear.

答案解析：

急性主动脉瓣关闭不全是一种需要及时手术干预的内科急症。然而，诊断往往具有挑战性，导致延误处理。与这里的情况一样，酷似肺炎或非瓣膜性心力衰竭的表现可能使情况复杂化，延误明确的治疗。考虑到舒张期杂音、心源性和感染性休克混合的证据、针道痕迹和血液培养耐甲氧西林金黄色葡萄球菌 (MRSA) 阳性，最可能的诊断是感染性心内膜炎引起急性主动脉瓣返流。

治疗应针对扩大抗生素覆盖范围以包括MRSA，立即获得超声心动图以确诊，并涉及心脏手术以明确治疗。有必要进行适当的药物治疗，包括血管加压药、正性肌力药和插管，但不能替代这种危重状态下的手术治疗。提供额外的 IV 液体推注不太可能改善低血压，并且考虑到心源性休克的证据，可能使氧合恶化。由于主动脉瓣关闭不全和舒张期间球囊充盈时返流恶化，此处禁忌放置主动脉内球囊泵。在这种情况下，延迟手术修复数天直至血培养恢复阴性不是最佳治疗。

正确答案：B