Published online May 15, 2006
PEDIATRICS
Vol. 117
No. 6
June 2006, pp.
e1259-e1262
(doi:10.1542/peds.2005-0897)
Ductus Arteriosus Aneurysm With Community-Acquired Methicillin-Resistant Staphylococcus aureus Infection and Spontaneous Rupture: A Potentially Fatal Quandary
Audra Stewart, DOa,
Umesh Dyamenahalli, MDa,
S. Bruce Greenberg, MDb and
Jonathan Drummond-Webb, MDc,
a Departments of Pediatrics, Cardiology Division
b Radiology
c Section of Pediatric and Congenital Cardiac Surgery, University of Arkansas for Medical Sciences, College of Medicine, and Arkansas Children's Hospital, Little Rock, Arkansas
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ABSTRACT
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We present the case of a 6-month-old previously healthy girl who presented with high fever, labored breathing, and an enlarged cardiac silhouette on her chest radiograph. Comprehensive evaluation discovered a ductus arteriosus aneurysm and pericardial effusion with methicillin-resistant Staphylococcus aureus bacteremia. Despite pericardiocentesis and appropriate intravenous antibiotics, there was rapid enlargement of the aneurysm and accumulation of echogenic material within the ductus arteriosus aneurysm. Infected aneurysm rupture was identified during emergency surgery. This infant also had vocal cord paresis, a likely complication of the surgery. The clinical course, diagnosis, and treatment of this patient are discussed. Infection of a ductus arteriosus or an infected ductal arteriosus aneurysm is a rare and potentially fatal clinical entity. In the era of increasing community-acquired methicillin-resistant S aureus infections, this is a diagnosis that requires a high index of suspicion.
Key Words: pediatrics • cardiology • ductus arteriosus aneurysm
Abbreviations: DAA, ductus arteriosus aneurysm • PDA, patent ductus arteriosus • MRSA, methicillin-resistant Staphylococcus aureus • ED, emergency department • CT, computed tomography • CA, community acquired
Ductus arteriosus aneurysm (DAA), a rare and potentially fatal condition, can be congenital or acquired after surgical ligation of patent ductus arteriosus (PDA). Characterized by a localized fusiform dilation of the ductus arteriosus,1 patients with connective tissue abnormalities such as Marfan syndrome, Ehlers-Danlos syndrome, and Larsen's syndrome may develop DAA. Complications that are discovered at autopsy include spontaneous rupture, erosion into adjacent structures, infection, thromboembolism, and compression of adjacent structures (airways).2 Only 1 report has documented culture-proven bacteremia as a cause of spontaneous childhood-infected DAA.3 To our knowledge, there are no reported cases of patients with culture-proven methicillin-resistant Staphylococcus aureus (MRSA)-infected DAA and spontaneous rupture that underwent successful surgical intervention and medical treatment. We report a 6-month-old infant who presented with septicemia and pericardial effusion along with DAA. Despite appropriate intravenous antibiotics, the DAA was rapidly enlarging in the presence of MRSA bacteremia and required urgent surgical intervention.
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CASE REPORT
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The patient, a black girl, was born at 37 weeks' gestation with a birth weight of 2.7 kg. Her neonatal course was complicated by hypoglycemia and emesis, and she had meconium plugs. The differential diagnoses of Hirschsprung's disease and necrotizing enterocolitis were ruled out. She received antibiotics empirically for 4 days and was discharged from the hospital. The patient's cardiorespiratory examination was normal, and she was in stable condition. She remained well until her presentation at 6 months of age to the pediatric emergency department (ED) with high fever; a fluctuant and purulent superficial abscess with purulent drainage in the parieto-occipital area of the scalp; and enlarged, tender cervical and occipital lymph nodes. The purulent material was sent for culture and sensitivity.
The infant had tachycardia and tachypnea; otherwise, she had no obvious abnormal cardiorespiratory findings on physical examination. The infant had a white cell count of 17400 cells per mL and a left shift. She was given 1 intravenous dose of ceftriaxone and discharged from the ED on clindamycin.
Two days later, she returned to the pediatric ED with continuing fever, increased labored breathing, and evidence of dehydration. Physical examination revealed that she was febrile, her pulse rate was 176 beats per minute, and she was in mild respiratory distress. The patient's oxygen saturation was 99% by pulse oximetry. There were enlarged posterior cervical lymph nodes, and she was noted to have a grade II/VI systolic murmur over the left upper sternal edge. A chest radiograph revealed a left upper lobe consolidation. A complete blood count blood culture, urinalysis, and urine culture were repeated. There was increased white cell count as well as increased band cells with toxic granulations (28300, with 35% band count). Because of left upper lobar pneumonia, cefprozil was prescribed in addition to the clindamycin. Wound culture grew MRSA, but it was sensitive to clindamycin, tetracycline, and trimethoprim/sulfamethoxazole. The blood culture also grew coagulase-positive Staphylococcus that later was identified as MRSA (the patient was registered with a different family name; therefore, the ED physician was not aware of the culture results).
Within the next 2 days, she continued have poor feeding and a fever. She developed increasing respiratory distress along with grunting, diarrhea, and decreased urine output. Vital signs revealed a temperature of 38.8°C, pulse of 180 beats per minute, respiratory rate in the 80s, and oximetry saturations in the mid-90s. Physical examination revealed respiratory distress (tachypnea, nasal flaring, grunting, and subcostal retractions), and pericardial rub was detected. Her white blood cell count at this time was 38800 cells per mL, and a repeat chest radiograph revealed an enlarged cardiac silhouette and persistence of left upper lobe consolidation. She therefore was admitted to the hospital for intensive treatment.
Blood cultures were repeated, and she was started on intravenous vancomycin and cefotaxime. An echocardiogram revealed good biventricular systolic function and a large pericardial effusion as well as fibrinous material within the pericardial fluid. Surgical pericardiocentesis was performed. A follow-up echocardiogram revealed very small PDA by color Doppler and presence of a large DAA that measured 2 cm, which then was confirmed by computed tomography (CT) of the chest (Fig 1). In addition to DAA, CT scan revealed rightward deviation of the esophagus and compression of the trachea by DAA. Repeat echocardiography revealed increasing size of the DAA without PDA, and the DAA was filled with echogenic tissue, probably pus (Fig 2).
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FIGURE 1 Frontal view of spiral CT angiogram showing protrusion of DAA. BCV indicates brachiocephalic vein; AAO, ascending aorta.
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FIGURE 2 Left postero-oblique view of spiral CT angiogram showing DAA with deviation of the subclavian artery (SA). DAO indicates descending aorta.
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Rupture of the DAA was suspected because of clinical deterioration, and the patient underwent emergency surgery. The procedure was performed through a median sternotomy, under cardiopulmonary bypass and deep hypothermic circulatory arrest. A ruptured ductal aneurysm was leaking into the left pleural space. The aneurysm was resected, and a pericardial patch was used to close the defect in the descending thoracic aorta and aortic arch. The aneurysm tissue culture that was collected at the time of surgery was positive for MRSA. The histopathology was not performed on the necrotic tissue. The patient received intravenous vancomycin for 6 weeks. Her postoperative course was complicated by left vocal cord palsy, and she required prolonged ventilatory support for sepsis-related pulmonary parenchymal disease. In addition, she developed subglottic granuloma that required laser therapy. The patient was discharged from the hospital 7 weeks after admission. A follow-up CT scan after 
7 months after surgery showed a normal aortic arch, and the patient has been thriving and has no clinically significant respiratory abnormalities.
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DISCUSSION
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Postnatal spontaneous closure of the ductus arteriosus usually begins at the pulmonary end and progresses toward the aorta.4 Fibrous tissue replaces the muscular tissue of the ductus arteriosus, resulting in the ligamentum arteriosum. A DAA may be a result of decreased intimal cushion formation that takes place during the third trimester of pregnancy. An aneurysm may be the result of abnormal elastin deposition that might happen during a later part of the pregnancy and that would weaken vessel walls, particularly in connective tissue disorders such as Marfan syndrome or Ehlers-Danlos syndrome.1,2 Similarly, the necrosis or inflammation of the ductus arteriosus would result in a weakened vessel wall with subsequent ballooning of the wall because of high aortic pressures and possibly turbulence. Over time, this eventually may lead to rupture. A literature review by Lund et al1 reported 106 spontaneous DAAs and 38 postsurgical DAAs. In that review, patients who were younger than 2 months accounted for the majority of cases (65 of 106). Although DAAs are associated with severe and life-threatening complications, many affected infants have a benign course.2
The prospective study by Jan et al5 reported a high (8.8%) incidence of isolated DAAs in term newborns. All cases were confirmed using echocardiogram, and all of the cases were asymptomatic and regressed by 35 days of life. That study supports the idea that infant DAAs may be a normal anatomic variant that regresses with age. In their observation, no clinically important DAA were reported after the neonatal period.
DAAs can be present either with or without PDA.1–5 With the improved technology, echocardiography has become the primary mode to detect DAAs. Recently, ante partum detection of DAAs has been reported followed by appropriate and successful surgical management. Patients with DAA require surgery under cardiopulmonary bypass for resection and patch closure of the defect at the aortic and sometimes also at the pulmonary arterial end. To our knowledge, our patient is the first reported case of community-acquired (CA) MRSA–infected DAA and spontaneous rupture to undergo successful surgical intervention and medical management. Botta et al,3 however, reported an infant with acquired DAA secondary to arteritis with methicillin-sensitive S aureus infection. Marcinak and Frank6 reported increased incidences of CA MRSA in children even though they were not known to be exposed to risk factors such as receiving antibiotics within the previous 6 months, child care attendance, chronic illness, or previous hospitalization. A study published from Texas Children's Hospital in Houston suggested that skin and soft tissue infections accounted for 89% of CA-MRSA infections.7 In addition to minor infections, CA MRSA has been attributed to serious infections, including bacteremia, pneumonia, pyomyositis, septic arthritis, osteomyelitis, and lymphadenitis.6
The infant we report had 3 of the 6 listed risk factors to acquire MRSA infection; she had been hospitalized and received antibiotics in the previous 6 months and had visited the outpatient clinic 5 times since birth. She presented with a potentially life-threatening complication of MRSA infection. MRSA initially was isolated from a scalp abscess, probably the primary site. Then the patient probably developed systemic infection that caused fibrinous pericarditis, pneumonia, and infection of the DAA. Infection probably further weakened the ductal wall, which further led to the spontaneous rupture of the DAA. In addition to echocardiography, the chest CT scan helped to define the DAA.
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CONCLUSIONS
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To our knowledge, this is the only documented patient with culture-proven CA-MRSA–infected DAA and spontaneous rupture who successfully underwent a surgical resection that resulted in an excellent outcome. This case serves to highlight a rare and potentially devastating cardiovascular complication that may arise from CA-MRSA infection.
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ACKNOWLEDGMENTS
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We thank Suzanne Speaker for assistance with manuscript preparation.
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FOOTNOTES
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Accepted Dec 22, 2005.
Address correspondence to Umesh Dyamenahalli, MD, University of Arkansas for Medical Sciences, College of Medicine, Department of Pediatrics, Arkansas Children's Hospital, 800 Marshall St, #512-3, Little Rock, AR 72202. E-mail: dyamenahalliUmesh{at}uams.edu
The authors have indicated they have no financial relationships relevant to this article to disclose.
Deceased 
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