A 4-week-old male infant with hypoplastic left heart syndrome has had difficulty feeding and an episode of vomiting over the last 24 hours. He was born at term via normal spontaneous vaginal delivery. The patient underwent palliative heart surgery at age 1 week; the procedure involved cardiotomy and extensive intracardiac and aortic arch repair. His postoperative course was uncomplicated, and he has remained in the hospital for weaning of oxygen and titration of cardiac medications. Two additional palliative surgeries are planned. Temperature is 38.3 C (101 F), blood pressure is 80/40 mm Hg, pulse is 175/min, and respirations are 70/min. Pulse oximetry is 80% on room air. He is cyanotic and small for his age. Cardiopulmonary examination is notable for distant heart sounds, tachycardia, and tachypnea. Abdominal examination is normal. Chest radiographs from a week ago and today are shown below. Which of the following is the most likely cause of this patient's acute presentation?

Question

A 4-week-old male infant with hypoplastic left heart syndrome has had difficulty feeding and an episode of vomiting over the last 24 hours.  He was born at term via normal spontaneous vaginal delivery.  The patient underwent palliative heart surgery at age 1 week; the procedure involved cardiotomy and extensive intracardiac and aortic arch repair.  His postoperative course was uncomplicated, and he has remained in the hospital for weaning of oxygen and titration of cardiac medications.  Two additional palliative surgeries are planned.  Temperature is 38.3 C (101 F), blood pressure is 80/40 mm Hg, pulse is 175/min, and respirations are 70/min.  Pulse oximetry is 80% on room air.  He is cyanotic and small for his age.  Cardiopulmonary examination is notable for distant heart sounds, tachycardia, and tachypnea.  Abdominal examination is normal.  Chest radiographs from a week ago and today are shown below.  Which of the following is the most likely cause of this patient's acute presentation?

Quizplus · Accepted Answer

11ec25c8_d637_554a_bc81_85cbe58bf662_MD0003_00 This patient with recent cardiac surgery developed tachycardia, tachypnea, distant heart sounds, and enlargement of the cardiac silhouette on chest x-ray, suggestive of pericardial effusion. A pericardial effusion occurs when inflamed pericardial cells produce increased fluid, which accumulates in the pericardial sac around the heart. This is common a few weeks after cardiac surgery due to immune-mediated inflammatory damage to the pericardium (ie, postpericardiotomy syndrome). Small pericardial effusions are usually asymptomatic because the pericardium stretches to accommodate the fluid. However, larger effusions can compress the heart and impair cardiac filling. Infants can develop decreased appetite and vomiting whereas older children may present with pericardial friction rub and pleuritic chest pain. Fever may be present due to inflammation, and tachypnea and tachycardia occur in response to decreased cardiac output. The effusion obscures auscultation, causing distant, "muffled" heart sounds on examination. Fluid accumulation around the heart causes an enlarged cardiac silhouette on chest x-ray, as seen in this patient. Costophrenic angles remain sharp unless there is an accompanying pleural effusion, and the stomach bubble is a normal finding that can be seen. Echocardiogram confirms the diagnosis. Patients with signs of hemodynamic compromise should undergo drainage of pericardial fluid. (Choice A) Congestive heart failure is a complication of congenital heart disease that can present with poor feeding and tachycardia. However, pulmonary vascular congestion (represented in an adult patient in the exhibit) and interstitial edema would be expected on chest x-ray. pulmonary vascular congestion (Choice B) Children with congenital heart disease are at increased risk for bacterial endocarditis. Presentation includes fever and tachycardia; however, a new murmur, not distant heart sounds, would be present on examination. Other findings consistent with endocarditis include petechiae, splinter hemorrhages, and Janeway lesions. (Choice C) Postoperative mediastinitis can complicate heart surgery and present with fever and tachycardia. However, it is classically associated with sternal wound erythema and drainage; and rather than showing an enlarged cardiac silhouette, chest x-ray may show mediastinal widening, although this finding is often absent in cases of postoperative mediastinitis (compared to mediastinitis due to esophageal rupture or odontogenic/retropharyngeal infection spread). (Choice E) Pulmonary embolism can present with tachycardia, tachypnea, hypoxia, and right heart failure. Chest x-ray is usually normal. This patient's hypoxia is typical of hypoplastic left heart syndrome following the first palliative surgery and is not indicative of pulmonary embolism. Educational objective: Pericardial effusion can occur after cardiac surgery and typically presents with distant, "muffled" heart sounds and signs of decreased cardiac output (eg, tachycardia, tachypnea). An enlarged cardiac silhouette on chest x-ray is characteristic. References: Post-pericardiotomy syndrome. (http://www.ncbi.nlm.nih.gov/pubmed/27761786)

A 4-Week-Old Male Infant with Hypoplastic Left Heart Syndrome Has