Small Pulmonary Artery



Small Pulmonary Artery


Alexander J. Towbin, MD



DIFFERENTIAL DIAGNOSIS


Common



  • Congenital Venolobar Syndrome



    • Scimitar Syndrome


    • Pulmonary Hypoplasia


  • Tetralogy of Fallot


Less Common



  • Pulmonary Stenosis


  • Supravalvular Aortic Stenosis


Rare but Important



  • Takayasu Arteritis


  • Alagille Syndrome


  • Rubella


  • Ehlers-Danlos Syndrome


  • Cutis Laxa


ESSENTIAL INFORMATION


Key Differential Diagnosis Issues



  • 2 broad categories: Congenital venolobar syndrome and pulmonary stenosis


Helpful Clues for Common Diagnoses



  • Congenital Venolobar Syndrome



    • Heterogeneous group of pulmonary developmental anomalies



      • Most consistent components are hypogenetic lung and partial anomalous pulmonary venous return


      • Includes scimitar syndrome, partial anomalous pulmonary venous return, congenital absence of pulmonary artery, and pulmonary sequestration


    • Pulmonary sequestration is most common


    • Patients are usually asymptomatic


    • Associations: Cardiac and spinal anomalies


  • Scimitar Syndrome



    • a.k.a hypogenetic right lung


    • Specific type of congenital venolobar syndrome



      • Definition: Scimitar vein with right-sided pulmonary hypoplasia and systemic collaterals vessels to right lung


    • Scimitar vein: Partial anomalous pulmonary venous return from right lung to inferior vena cava



      • Courses anterior and inferior from hilum to diaphragm


      • Can insert in inferior vena cava or right atrium


    • 2 types: Infantile and pediatric/adult



      • Infantile form presents with failure to thrive, tachypnea, and heart failure; 45% mortality


      • High incidence of other congenital heart defects (CHD) in infantile form


      • Pediatric/adult form is usually incidental finding on chest x-ray (CXR)


  • Pulmonary Hypoplasia



    • Small lung with alveoli and bronchi present


    • CXR: Small hemithorax, small hilum, and ipsilateral mediastinal shift: Ipsilateral ↓ pulmonary vascularity


    • More common on right


  • Tetralogy of Fallot



    • Combination of 4 cardiac defects



      • Ventricular septal defect, overriding aorta, subpulmonic stenosis, and right ventricular hypertrophy


    • Most common cyanotic heart disease


    • Accounts for 10% of CHD


    • Classic CXR with boot-shaped heart



      • Due to upward displacement of cardiac apex and narrowed mediastinum from hypoplastic pulmonary outflow tract


    • Associated with trisomy 21, 18, or 13 and DiGeorge syndrome


Helpful Clues for Less Common Diagnoses



  • Pulmonary Stenosis



    • Types: Valvular, subvalvular, supravalvular, or in branch pulmonary arteries


    • Valvular stenosis is most common



      • 7-9% of all CHD


      • Present with asymptomatic murmur


      • CXR: Dilated main pulmonary artery, small peripheral vessels


      • Treatment: Balloon valvuloplasty


  • Supravalvular Aortic Stenosis



    • Supravalvular is least common type of aortic stenosis



      • Narrowing of aortic root at or above sinotubular ridge


      • Accounts for < 10%


      • Frequently seen in Williams syndrome


      • Association: Pulmonary artery stenosis


Helpful Clues for Rare Diagnoses



  • Takayasu Arteritis



    • Chronic vasculitis of unknown etiology



    • Large vessel vasculitis affects aorta, its main branches, and pulmonary arteries


    • 3rd most common vasculitis of childhood



      • Most commonly presents between 10-20 years of age


      • 8.5x more common in females


    • Associated with tuberculosis infection


    • Pulseless arteritis is characteristic of chronic disease


    • Pulmonary arteries involved in ˜ 85%


    • Often leads to hypertension, congestive heart failure, or aortic regurgitation


    • CXR aorta: Undulating border, segmental calcification


    • CXR pulmonary arteries: Oligemia


    • CT or MR shows thickened arterial wall with enhancement


    • Treated with steroids


  • Alagille Syndrome



    • Genetic disorder


    • Characterized by 5 major features



      • Paucity of bile ducts, peripheral pulmonary stenosis, “butterfly” vertebral bodies, posterior embryotoxon, and abnormal facies


      • Also associated with complex CHD


    • 20-25% require liver transplant


  • Rubella

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Aug 10, 2016 | Posted by in PEDIATRICS | Comments Off on Small Pulmonary Artery

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