Challenging Cases in Neonatology: Cases from NeoReviews 'Index of Suspicion in the Nursery' and 'Visual Diagnosis'

Challenging Cases in Neonatology: Cases from NeoReviews 'Index of Suspicion in the Nursery' and 'Visual Diagnosis'

by Dara Brodsky

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Product Details

ISBN-13: 9781610021401
Publisher: American Academy of Pediatrics
Publication date: 06/01/2018
Pages: 377
Sales rank: 1,279,466
Product dimensions: 6.50(w) x 9.40(h) x 0.80(d)

About the Author


Dara Brodsky, MD, FAAP,NeoReviews Deputy Editor; Associate Editor, Visual Diagnosis, Video Corner. Dr. Brodsky is a neonatologist at Beth Israel Deaconess Medical Center (BIDMC), an Associate Director of the BIDMC Neonatal Intensive Care Unit, the Director of Education in the BIDMC Department of Neonatology, and an Assistant Professor in Pediatrics at Harvard Medical School (HMS). She is very involved in medical education at HMS and in the Harvard Neonatal-Perinatal Medicine Fellowship Program. She is a co-director of the Newborn Medicine Summer Student Research Program at Boston Children's Hospital, a Principal Clerkship Experience Advisor at BIDMC for 7-11 Harvard Medical Students students/year and an active member of the Academy at Harvard Medical School. She has co-authored 3 books to assist trainees and neonatologists with board review: Neonatology Review, Neonatology Review: Images, and Neonatology Case-Based Review. She is also co-editor of the textbook Primary Care of the Premature Infant and Neonatology Review: Q & A. She served as an editorial board member of the American Academy of Pediatrics (AAP)-sponsored online NeoReviewsPlus and currently is Deputy Editor of the AAP-online journal NeoReviews and Associate Editor of the Visual Diagnosis and Video Corner section. In recognition for her teaching efforts, she received the 2010 Merton Bernfield Award for mentoring neonatology fellows in the Harvard Fellowship Program, the BIDMC Academy of Medical Educators award in 2013, the HMS Medical Student Teaching Award in Pediatrics in 2013, the Richard Rivas Memorial Great Teacher Award in 2015 for her talks at the board review course Specialty Review in Neonatology, and the R. Stone Award for Excellence in Teaching at BIDMC.
 
 
Josef Neu, MD, FAAP, NeoReivews Associate Editor. Dr. Neu is Professor, Department of Pediatrics, Division of Neonatology at University of Florida Health; he received his Bachelor of Arts Degree in 1971, at Wisconsin State University, Whitewater, WI. In 1975 he received his Medical Doctorate, University of Wisconsin, Madison, WI. Dr. Neu completed his Pediatrics Residency at John Hopkins Hospital, Baltimore, MD from 1975-1978, 1978-1980 Postdoctoral Fellow in Neonatology, Stanford University Medical Center, Stanford, CA. In 1987 he completed his Sabbatical, Inselspital, at the University of Bern, Switzerland.

Read an Excerpt

CHAPTER 1

CASE 1

Inconsolable Crying While Feeding

Presentation

A nurse in the neonatal intensive care unit reports that a 5-week-old male infant has tachypnea. He has had acute episodes of irritability while being fed formula for the past week. He had been delivered by cesarean section because of late fetal decelerations at 29 weeks' gestation. At birth, he had mild respiratory distress syndrome that required bubble continuous positive airway pressure for 48 hours. He initially received intravenous fluids and gradually was started on feedings.

Despite receiving full nipple feedings for the past week, he has not gained weight appropriately. The fussiness while feeding initially had been attributed to gastroesophageal reflux.

On physical examination today, the infant's temperature is 36.5°C, heart rate is 178 beats/min, respiratory rate is 76 breaths/min, blood pressure is 56/28 mm Hg, and oxygen saturation is 98% on room air. His weight is 2 kg, length is 42 cm, and head circumference is 30 cm. He has no obvious facial dysmorphisms. The capillary refill time is prolonged (5 sec), and he has feeble pulses, cool extremities, nasal flaring, and subcostal retractions.

Cardiac auscultation demonstrates a gallop rhythm and a 4/6 holosystolic mur- mur radiating to the left axilla. The liver is palpable 5 cm below the costal margin. Chest examination reveals bilateral rales. The remainder of the physical findings are unremarkable.

Complete blood count and metabolic profile yield normal results. Chest radiograph shows an enlarged cardiac silhouette (Figure 1.1). The infant's 12-lead electrocardiography (ECG) is shown in Figure 1.2. Further investigation confirms the diagnosis.

Discussion

Diagnosis

The clinical diagnosis was congestive heart failure, and intravenous fluids and milrinone were initiated. Echocardiography revealed an enlarged, poorly contracting left ventricular chamber with an ejection fraction of 25% and a moderate degree of mitral valve regurgitation. The left atrium was enlarged, with bowing of the interatrial septum. A prominent right coronary artery originated from the right aortic cusp, with a smaller left coronary artery (LCA) arising from the pulmonary artery (PA). Color flow imaging demonstrated retrograde flow into the PA. Based on these findings, the final diagnosis was left ventricular cardiomyopathy due to anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA).

Differential Diagnosis

The differential diagnosis of heart failure in an infant can be left-to-right shunts (ventricular septal defect), left-sided obstructive lesions, myocarditis, metabolic disorder (hypocalcemia), arrhythmias, arteriovenous malformation (vein of Galen, hepatic, pulmonary), coronary ischemia (ALCAPA, Kawasaki disease), or acute hypertension. Electrocardiography can help in delineating the cause of heart failure in infants.

The Condition

Anomalous origin of the left coronary artery from the pulmonary artery may occur as an isolated defect or in association with other congenital heart defects such as patent ductus arteriosus, tetralogy of Fallot, or truncus arteriosus. It is also known as Bland-White-Garland syndrome. Its incidence is approximately 1 in 300,000 live births. Embryologically, ALCAPA results from abnormal septation of the conotruncus or abnormal persistence of pulmonary artery coronary buds and abnormal involution of aortic coronary buds.

Pathophysiology

The clinical manifestations of patients who have ALCAPA usually are evident by 2 to 3 months of age. During the newborn period, there is antegrade blood flow from the PA to the LCA. Because pulmonary vascular resistance (PVR) is elevated in the neonate, myocardium supplied by the LCA is not ischemic, even though it is perfused by desaturated blood from the PA. As the PVR falls at around 6 to 8 weeks of age, flow to the LCA is severely compromised. To compensate, collateral anastomoses between right and left coronary arteries ensue. With further decline in PVR, blood flow reverses from the LCA into the PA. This phenomenon is known as coronary steal syndrome and results in myocardial ischemia. Mitral valve regurgitation is a frequent complication and is due to papillary muscle infarction and dilated mitral valve annulus.

Clinical Presentation

The initial symptoms of ALCAPA include poor feeding, pallor, and paroxysms of crying, irritability, or diaphoresis and represent angina pectoris. A high index of suspicion is required because the fussiness might be falsely interpreted as infantile colic or reflux. Congestive heart failure often is precipitated by a viral respiratory infection that further increases myocardial oxygen demand. Wheezing may masquerade as bronchiolitis. Examination demonstrates a gallop rhythm or holosystolic murmur (due to mitral regurgitation). Rarely, the symptoms are not apparent until late childhood or adolescence or even adulthood if there are abundant intercoronary anastomoses. On examination, this group of patients may have continuous murmurs. They present with exercise-induced chest pain, syncope, or sudden death.

Laboratory Findings

Chest radiography shows cardiomegaly. Electrocardiographic findings are consistent with lateral wall myocardial ischemia and include deep Q waves in lead I, aVL, and V4 through V6. Left ventricular leads (V4 to V6) may exhibit ST segment elevation and inverted T waves. Two-dimensional echocardiography may suggest the diagnosis, but Doppler color flow mapping improves the diagnostic accuracy and may demonstrate retrograde flow in the left coronary artery. Abnormal echogenicity of left ventricular papillary muscles may be an additional finding. Abnormal dilation of the proximal right coronary artery is a marker for extensive collateral circulation. Cardiac catheterization with coronary angiography is the gold standard for diagnosis but is necessary only when the diagnosis is ambiguous.

Management

Surgical revascularization is the definitive treatment. It consists of removal of the LCA from the PA and reimplantation into the aorta. Ligation of the anomalous LCA at its origin from the PA or creation of an intrapulmonary artery baffle from the aortic root to the LCA (Takeuchi procedure) that were performed historically have been abandoned.

Without surgical intervention, mortality is more than 90% in infancy. Patients who survive beyond infancy usually have extensive intercoronary arterial anastomoses. Cardiac transplantation may be considered for infants who have significant myocardial infarction.

Long-term prognosis is variable and depends upon the degree of myocardial infarction sustained before surgical intervention.

Lessons for the Clinician

Anomalous origin of the left coronary artery from the pulmonary artery is one of the important causes of dilated cardiomyopathy in infants. The symptoms include poor feeding, pallor, and paroxysms of crying, irritability, or diaphoresis and represent angina pectoris. The age of presentation may vary. A high index of suspicion is required because it may mimic infantile colic, gastroesophageal reflux, or viral bronchiolitis. Electrocardiography shows features of myocardial ischemia. Two-dimensional echocardiography may suggest the diagnosis, but Doppler color flow mapping improves the diagnostic accuracy. Surgical revascularization is the definitive treatment.

CHAPTER 2

CASE 2

Newborn With Inaudible Heart Sounds

Presentation

A 2,216-g baby boy is born at 37 weeks' gestation to a 34-year-old gravida 2, para 1 woman. The pregnancy was uncomplicated until the day prior to delivery, when a biophysical profile score of 4/8 was obtained on assessment. Fetal heart rate decelerations to 80 beats/min and multiple late decelerations are noted the evening of delivery, and an emergent cesarean section is planned. The male infant is delivered precipitously prior to entering the operating room. Placental abruption is evident after delivery. At birth, the baby is limp but has spontaneous respirations, with a respiratory rate of 60 breaths/min. Mild intercostal retractions are evident. Femoral pulses are weak, but the heart rate is detected at 130 beats/min. On auscultation, heart sounds are not audible. Apgar scores are 7, 7, and 8 at 1, 5, and 10 minutes, respectively.

Shortly after initial assessment, continuous positive airway pressure (CPAP) is applied at 4 to 5 cm H2O, and the baby is transported to the neonatal intensive care unit, where the blood pressure is 44/16 mm Hg (mean, 27 mm Hg) and the oxygen saturation is 98% (with CPAP). Color and tone are poor, and the baby subsequently receives bag-and-mask ventilation and a bolus of 10 mL/kg normal saline via a peripheral intravenous infusion. Color and perfusion do not improve with these interventions. Chest radiography is obtained at 1 hour after delivery, and electrocardiography shows low voltages in all leads. Umbilical venous and arterial lines are inserted, and the baby is intubated with a 3.0 endotracheal tube after receiving atropine, morphine, and succinylcholine. Mechanical ventilation is initiated on initial settings of rate, 40 breaths/min; inspiratory pressure, 12 cm H2O; expiratory pressure, 4 cm H2O; and FiO2, 0.6. A dopamine infusion is started, running at a rate of 10 mcg/kg per minute. Blood pressure and perfusion show minimal improvement despite inotropic support. Arterial cord pH is 7.15, and initial blood counts show white blood cell count, 15.5×103/mcL (15.5×109/L); hemoglobin, 14.9 g/dL (149 g/L); and platelets, 131×103/mcL (131×109/L). Arterial blood gas measurements obtained after intubation show pH, 7.32; PCO2, 36 mm Hg; PaO2, 64 mm Hg; HCO3, 18 mmol/L. A chest radiograph is shown in Figure 2.1.

Discussion

Shock in a newborn has a relatively wide differential diagnosis, including hypovolemic shock (eg, placental abruption), septic shock (eg, group B streptococcal infection), and even cardiogenic shock from asphyxia or congenital heart disease. This case is unique in its clinical presentation because the heart sounds were not audible at birth, electrocardiographic voltages were low, and the neonate's perfusion showed minimal response to fluids or dopamine. The initial radiograph obtained at 1 hour after delivery (Figure 2.2) revealed a spontaneous pneumopericardium (PPC) from birth.

Cause and Pathogenesis

The exact cause of PPC remains unknown, but many authors have speculated that interstitial pulmonary air dissects into the mediastinum, entering the pericardial space at the reflection of the pericardial membrane and the pulmonary vessels. In a retrospective review of 50 neonates who had PPC, the most common risk factors were prematurity, low birthweight, presence of respiratory distress syndrome, and the requirement for mechanical ventilation. Other contributory factors were a history of cardiopulmonary resuscitation with intracardiac drug administration and improper endotracheal tube placement. There have been several case reports of neonatal PPC in the absence of mechanical ventilation, usually associated with significant lung disease or the provision of continuous positive airway pressure prior to clinical deterioration. However, spontaneous PPC from birth also has been reported, presenting with an absence of heart sounds and poor perfusion in the delivery room.

Clinical Presentation

This patient had a typical clinical presentation for PPC. Cyanosis, muffled heart sounds, hypotension, and poor capillary refill are the key components to quick diagnosis. Bradycardia also has been noted in 52% of affected neonates. Cardiac tamponade and cardiac arrest represent one severe end of the spectrum of illness caused by PPC. On the other end of the spectrum are patients who remain asymptomatic and never progress to the development of cardiac tamponade despite radiographic confirmation of the diagnosis. In fact, this was described as early as 1974 in a case series published by Varano: "Although the radiograph suggested the presence of significant amounts of pericardial air, no tamponade was apparent (blood pressure remained constant), and spontaneous resolution of the pneumopericardium occurred."

Radiographic Features

The radiographic appearance of PPC has been described best as the classic "halo" sign: a continuous radiolucent band of air conforming to the shape of the heart. In some cases a pericardial line also may be detected, extending inferolaterally from the pericardial reflection at the great vessels. At times, it may be difficult to distinguish PPC from other forms of air leak, such as a pneumomediastinum or a pneumothorax. These conditions may be differentiated by noting that air in the pericardial space may extend inferior to the heart, with air in the mediastinum or pleural cavity typically not present.

Management

The management of PPC is dictated by the clinical presentation of the patient. Asymptomatic infants usually do not require direct intervention. Those who have signs of cardiac tamponade need immediate treatment with pericardial decompression (Figure 2.3). Emery and associates have reported recurrences of PPC in 100% of newborns who had severe respiratory disease, leading to the suggestion that placement of an intrapericardial suction catheter is prudent for successful management. However, pericardial drainage catheters have been complicated by hemopericardium, resulting in death by tamponade. Thus, pericardial drainage tubes probably should be reserved for infants in whom PPC with tamponade recurs, where a drainage tube potentially could be lifesaving.

Lessons for the Clinician

Pneumopericardium should be considered in the differential diagnosis of a newborn in shock, particularly those in whom heart sounds are absent and who do not show clinical improvement with fluid resuscitation. A clinical diagnosis can be made rapidly by demonstration of a classic halo sign on chest radiography. Treatment via pericardiocentesis to evacuate pericardial air is indicated in infants who demonstrate cardiovascular instability.

CHAPTER 3

CASE 3

Noisy Breathing Since Birth

Presentation

A 4-week-old male neonate presents to the clinic with a history of "noisy breathing since birth." His mother reports that the noise is unaffected by crying, feeding, agitation, or position. She denies any history of fever, cyanosis, vomiting, choking, diaphoresis, murmur, or seizures. The infant was born at term, weighing 3,600 g, to a primigravid mother via normal vaginal delivery, and there were no perinatal complications. There are no findings of note on family history. The child is gaining weight satisfactorily on formula feedings.

On physical examination, the well-nourished infant appears in no apparent distress. His temperature is 37.0°C, heart rate is 127 beats/min, respiratory rate is 36 breaths/ min, and blood pressure is 66/44 mm Hg. Oxygen saturation is 96% on room air. Capillary refill time is 2 seconds, with good peripheral pulses and warm extremities. There is no obvious facial dysmorphism or cutaneous hemangioma. Coarse inspiratory stridor is apparent, and chest auscultation reveals coarse breath sounds in all areas. The rest of the physical findings are normal. Chest radiography provides hints about the cause of stridor (Figure 3.1). Additional evaluation confirms the diagnosis.

Discussion

Chest radiography revealed a right-sided aortic arch and indentation of the trachea at the level of the arch (Figure 3.1). The cardiac silhouette appeared normal and the lung fields were clear. Because a vascular abnormality was suspected, magnetic resonance angiography of the chest was performed, and it demonstrated a right-sided aortic arch with mirror-image branching (Figure 3.2). A diverticulum of Kommerell was apparent, with narrowing of the trachea at the level of the arch to the level of the proximal mainstem bronchi (Figure 3.3). The narrow portion measured approximately 40% compared with the proximal trachea at the level of thoracic inlet.

(Continues…)


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Table of Contents


Cardiology
Dermatology
Endocrinology
Fluids and Electrolytes
Gastro-enterology
Genetics
Hematology & Oncology
Inborn Errors of Metabolism
Maternal-Fetal Medicine
Nephrology
Neurology
Orthopedics/Skeletal system
Otolaryngology
Pulmonology
 

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