Updated: 4/17/2018

Patent Ductus Arteriosus

Review Topic
  • A 3-year-old boy presents to his pediatrician’s office for a well-child visit. He recently moved to the United States from Vietnam. He and his parents report no concerns. On physical exam, he is not in acute distress. His cardiac exam reveals a continuous machine-like murmur. There is no cyanosis or respiratory distress. The physician counsels the parents about this murmur and suggests an echocardiogram.
  • Clinical definition
    • a persistent opening between the aorta and pulmonary artery that fails to close in the immediate postpartum period
  • Epidemiology
    • demographics
      • female > male 2:1
      • most commonly in premature infants
    • risk factors
      • maternal rubella infection
      • premature infants
      • in utero alcohol exposure
  • Pathogenesis
    • the ductus arteriosus is normal in utero and typically closes hours after birth
      • patency of PDA is maintained by prostaglandin E2 (PGE2) synthesis and low oxygen tension
    • if unfixed, a large PDA can cause left-to-right shunting in the heart, which increases pulmonary blood flow and causes alterations in the pulmonary vasculature
      • shifting of blood from systemic circulation can cause cyanosis
      • over time, with severe defects, this eventually results in pulmonary hypertension and  Eisenmenger syndrome
  • Associated conditions
    • fetal alcohol syndrome
    • congenital rubella
    • neonatal respiratory distress syndrome
      • due to persistently low oxygen tension
    • ventricular septal defect
  • Prognosis
    • typically progresses over time
  • Symptoms
    • symptoms usually occur with larger defects
    • respiratory distress
    • poor feeding
    • poor weight gain
    • easy fatigability
  • Physical exam
    • cardiac auscultation
      • continuous “machine-like" or "to-and-fro” murmur
      • 2nd intercostal space in the left upper sternal border
    • wide pulse pressure
    • bounding arterial pulses
    • cyanosis and clubbing of lower extremities
    • signs of respiratory distress
      • tachypnea
      • grunting
      • nasal flaring
      • retractions during breathing
  • Radiography
    • indication
      • for all patients
    • views
      • chest
    • findings
      • enlarged pulmonary artery
      • increased pulmonary markings
      • cardiomegaly
  • Echocardiogram
    • indication
      • performed as a diagnostic test
      • most specific test
    • findings
      • ductal flow
      • increased left atrium to aortic root
  • Electrocardiography
    • indications
      • to assess for arrhythmias
    • findings
      • left ventricular hypertrophy can occur over time
  • Making the diagnosis
    • based on clinical presentation and echocardiogram
  • Ventricular septal defect
    • distinguishing factor
      • holosystolic murmur
  • Management approach
    • many lesions may close spontaneously
    • premature infants often need medical or surgical treatment
  • Medical
    • indomethacin
      • indication
        • first-line therapy for all patients who do not need the PDA
        • premature infants with PDA
    • prostaglandin E
      • indication
        • for patients who require PDA to survive
          • e.g. for patients with transposition of the great vessels
  • Operative
    • surgical closure
      • indication
        • failure of PDA to close after medical therapy
        • term infants with large PDAs
  • Heart failure
  • Eisenmenger syndrome
  • Infective endocarditis

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Questions (2)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2

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(M1.CV.75) A 14-year-old male presents to his primary care physician with complaints of shortness of breath and easy fatigability when exercising for extended periods of time. He also reports that, when he exercises, his lower legs and feet turn a bluish-gray color. He cannot remember visiting a doctor since he was in elementary school. His vital signs are as follows: HR 72, BP 148/65, RR 14, and SpO2 97%. Which of the following murmurs and/or findings would be expected on auscultation of the precordium? Review Topic

QID: 106761

Mid-systolic murmur loudest at the right second intercostal space, with radiation to the right neck




Holodiastolic murmur loudest at the apex, with an opening snap following the S2 heart sound




Left infraclavicular systolic ejection murmur with decreased blood pressure in the lower extremities




Continuous, machine-like murmur at the left infraclavicular area




Right supraclavicular continuous murmur which disappears with pressure on the internal jugular vein




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