Pulmonary embolism in a newborn Daniela Dinu 1, Martha Douglas-Escobar 1, Henri Justino 2 Sections of Neonatology 1 and Cardiology 2, Department of Pediatrics,

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  • Pulmonary embolism in a newborn Daniela Dinu 1, Martha Douglas-Escobar 1, Henri Justino 2 Sections of Neonatology 1 and Cardiology 2, Department of Pediatrics, Baylor College of Medicine, Texas Children’s Hospital Houston, TX
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  • Background Pulmonary embolism  Rare and often overlooked condition in children.  0.86 / 10000 pediatric hospital admissions are complicated by pulmonary embolism with a high mortality (30%).  True incidence in newborns is unknown, and likely underestimated because:  symptoms are subtle or masked by a primary respiratory disorder  there is a low index of suspicion  Even with increasing awareness pulmonary embolism remains a diagnostic challenge due to:  non-specific symptoms  wide range of risk factors  lack of an algorithm to rule out or confirm it  limitations resulting from the fact that most data about diagnostic methods were evaluated based on adults
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  • Case presentation – History  1 month old boy presented to the ED with a history of vomiting and diarrhea for 3 days.  10 days prior to this admission, the infant:  had similar complaints  was admitted to another hospital for 3 days  was discharged with presumptive diagnosis of rotavirus gastroenteritis  Birth history: full term baby, born via spontaneous vaginal delivery, no perinatal complications. Clinical course – Emergency Department  severely dehydrated, capillary refill 4 sec, unobtainable BP  received 3 boluses of normal saline (60 ml/kg)  underwent a full sepsis work-up and was started on IV antibiotics  CXR unremarkable  initial blood gas showed severe metabolic acidosis 6.9/26/35/6/-24  lactate = 1.7, ammonia = 58, glucose = 165
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  • Clinical course – NICU admission  After initial resuscitation in the emergency room:  vital signs were stable (T = 97.9, HR = 145, RR = 42, BP = 90/60, O 2 Sat = 97% on room air)  continued on IV fluids and antibiotics  received bicarbonate bolus for metabolic acidosis  repeat blood gas after volume resuscitation showed unchanged metabolic acidosis: 6.94/31/24/7/-25  platelet count on admission: 289000  6 hours after NICU admission he suddenly decompensated:  O 2 saturations 40-50% despite 100 FiO 2  very poor perfusion  agonal breathing  Emergently intubated, first ABG post-intubation: pH < 6.8, bicarbonate and base excess not calculated (too low).  After stabilization PICC line placed for vascular access.
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  • Clinical course – day 1  Metabolic acidosis persisted despite multiple bicarbonate boluses (pH: < 6.8 – 7.14, BE: -25 – -7).  Developed lactic acidosis, genetic consult was done, but a metabolic disease seemed unlikely; plasma aminoacids and urine organic acids were sent.  Echocardiogram showed:  significant elevated RV pressures (leftward bowing of the ventricular septum and right to left shunting through PFO)  depressed RV systolic function  concern for “moderate hypoplasia of the proximal right pulmonary artery” and “significant distal hypoplasia of the right pulmonary artery”.  iNO was started to control the pulmonary hypertension.  He developed hypotension and dopamine was started.  Started developing thrombocytopenia (platelet count = 79000 – 94000).
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  • Clinical course – day 2  Remained on mechanical ventilation.  Metabolic acidosis was better controlled on bicarbonate drip (bicarbonate range: 21 – 29, base excess range: -9 – -2).  Continued to have hypotension on pressor support (dopamine) and Milrinone was added for inotropic support.  Developed multiorgan failure with:  oliguric renal failure (creatinine = 1.4)  increased liver enzymes (ALT = 1316, AST = 6575, albumin < 1.5)  coagulopathy (PT/PTT/INR = 31.8/44.9/2.9)  Thrombocytopenia persisted (platelet count = 62000 – 72000).
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  • Clinical course – day 3  Repeated echocardiogram (due to lack of response to iNO) showed:  large echogenic mass in the right pulmonary artery, nearly occluding the lumen  moderately depressed RV systolic function  abnormal spectral Doppler in the proximal left pulmonary artery with continuous diastolic flow and low systolic peak velocity  Platelets = 53000, PT/PTT/INR = 19.8/32.6/1.6, fibrinogen = 95, D-Dimer > 20, protein C = 19, protein S = 22, AT III = 40.  Due to significant degree of renal impairment (creatinine clearance = 13), a CT with contrast was contraindicated, therefore he underwent cardiac catheterization.
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  • Cardiac catheterization: absent flow to the right lung and left lower lobe
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  • Clinical course  In the cardiac catheterization lab he underwent attempted thrombectomy, but not much clot was retrieved, and he became unstable with catheters placed into the pulmonary arteries; angiography showed he had significant proximal and distal clot burden in the RPA, and LLPA.  TPA was started:  initially infused at 0.1 mg/kg/h IV for 12 hours via PICC line  TPA then infused at 0.05 mg/kg/h IV via a 3 Fr catheter placed in MPA for 24 hours  returned to catheterization laboratory twice during TPA infusion for repeat angiography and clot maceration by balloon angioplasty  He was started on heparin drip which was continued for 20 days  CT angiogram showed partial resolution of the clot  switched to Lovenox SQ.
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  • Summary of hospital course Respiratory  Required mechanical ventilation for 14 days.  Developed bilateral pleural effusions that required drainage, complicated by bilateral pneumopericardium and pneumothorax.  Post-extubation received supplemental oxygen via nasal cannula for another 8 days, then weaned to room air. Cardiovascular  From day 1 of admission required vasopressor support (dopamine, epinephrine), gradually weaned after thrombectomy.  Required inotropic support with Milrinone for 14 days.  Pulmonary hypertension gradually improved after thrombolysis.
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  • Summary of hospital course Infectious disease  Blood, urine, stool, CSF, viral cultures, and HSV PCR were negative.  Received 72h of Vancomycin and 10 days of Cefotaxime IV. Hematological  The etiology of the hypercoagulability remained unknown, initially thought to be infectious, and possibly due to dehydration.  Protein C and S, lipoprotein A, homocysteine, anticardiolipin panel were normal.  Prothrombin mutation and Factor V Leiden mutation analyses negative.  Received TPA IV and through catheter, then heparin IV followed by SQ Lovenox.  Discharged home on Lovenox, will have repeat testing for protein C and S at 3 months of age.
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  • Summary of hospital course Genetics  Plasma amino acids and urine organic acids were sent initially due to severe metabolic acidosis unresponsive to bicarbonate infusion and lactic acidosis (lactate level = 7).  Although initial testing was abnormal, repeat testing showed normal results, and newborn screening was normal. Renal  Had oliguric renal failure shortly after hospital admission (peak creatinine = 1.9), which improved.  Required Lasix and peritoneal dialysis for a brief period for volume overload.  Developed hypertension treated with Captopril, which was continued on discharge.  Renal sonogram and Doppler were unremarkable.
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  • Conclusions  The diagnosis of pulmonary embolism was not considered initially, in a newborn with:  severe dehydration (risk factor for thrombosis) and shock  suspicious echocardiogram (pulmonary hypertension and right ventricular enlargement)  evidence of ventilation/perfusion mismatch  lack of response of pulmonary hypertension to iNO  evidence of consumption coagulopathy  age group that placed him at higher risk  Timely diagnosis and intervention (thrombolytic and/or anticoagulant therapy, or catheter-based or surgical intervention) could change the outcome in a potentially lethal condition.
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  • Conclusions To our knowledge this is the first case of pulmonary embolism in a newborn with no genetic predisposing factors for thrombosis, no proven infectious cause and no cardiac defect, managed successfully via catheter thrombolysis. Pulmonary embolism  should be considered in the differential diagnosis in newborns that present with shock, severe metabolic acidosis with evidence of ventilation/perfusion mismatch, and pulmonary hypertension unresponsive to conventional therapy.  remains one of the most commonly missed diagnosis with the highest rate of discrepancy between the clinical and post-mortem diagnosis.  additional diagnostic testing should be performed if there is clinical suspicion of pulmonary embolism. CT angiogram is gold standard, with high sensitivity and specificity, but carries a high radiation dose in a group particularly susceptible to radiation. Catheterization also carries radiation risk, but allows for possible thrombectomy or thrombus maceration to assist with thrombolysis.
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  • References  Abdurrahman, L. et al. – Acute Pulmonary Embolism in a Neonate: Precipitation During Cardiac Catheterization and Successful Treatment, Pediatric Cardiology 19:431–435, 1998.  Biss, T. et al. – Clinical features and outcome of pulmonary embolism in children, British Journal of Haematology, 142, 808–818.  Cardoso, M. et al. – Comparison between clinical diagnoses and autopsy findings in a pediatric intensive care unit in São Paulo, Brazil, Pediatric Critical Care Medicine 2006 Vol. 7, No. 5.  Feldman, J. et al. – Angiojet catheter-based thrombectomy in a neonate with postoperative pulmonary embolism, Catheterization and Cardiovascular Interventions 66:442–445 (2005).  Saad, R. et al. – Comparison between clinical and autopsy diagnoses in a cardiology hospital, Heart, published online 2007.  Swayer, T. et al. – Neonatal Pulmonary Artery Thrombosis Presenting as Persistent Pulmonary Hypertension of the Newborn, Pediatric Cardiology, Volume 30, Number 4, May 2009.