Innocent pediatric murmurs

Background

Clinical Features
  • Goal to distinguish innocent (benign) murmurs from clinically significant pathology
  • Red flag features that may point to pathology, not innocent murmurs:
    • Poor weight gain: check height and weight- left-to-right can cause decrease in weight, but are usually symptomatic
    • Color - cyanosis of hands, feet, perioral on exertion
    • Feeding - fatigue or short feeding times for infants- perspiring, grunting, coughing, tachycardia while feeding. Severe CHF may show at rest deep breathing with dyspnea with distress
    • Enlarged heart (ie ASD) can cause bulging of chest
    • Older kids - activity causing dyspnea/cyanosis- keeping up with peers, grunting, coughing, tired from stairs. syncope/presyncope, fatigue, palpitations/angina can occur with hypertrophic cardiomyopathy
    • Yet older - Aortic valve with rheumatic fever, myocarditis (history of URI), endocarditis (IV drug use)
    • Pregnancy history - Maternal diabetes (ASD, coarctation of the aorta, cardiomyopathies), CMV, Coxsackie B5, warfarin, AEDs use, EtOH (ASD,VSD), prematurity (PDA)
    • Worry when - family history of [[HCM]]/sudden death and prominent apical thrust (indicates LVH)

Differential Diagnosis

Valvular Emergencies

Evaluation
  • Most innocent murmurs are
    • Not holo or diastolic
    • Not >grade III
    • Hockey stick dist
    • Normal S1 & S2

Types

Still's
  • Mid-Systolic, best at left lower sternal border, likely from harmonic vibrations of LV outflow tract (chordae tindinae)
  • All ages, particularly young school age
  • Low pitch, musical
  • Decreased with inspiration, sitting, standing. Not a VSD- not regurgitant or with thrill

Innocent Pulmonary Flow Murmur
  • Systolic best at left upper sternal border, minor turbulence in RV outflow tract and main pulmonary artery
  • Often infants and preschool age. Higher pitched than still's, less musical
  • Not PS- no ejection click, no increased RV impulse. no wide s2 split
  • Not Pulm M of ASD, no fixed splitting, no diastolic tricuspid flow rumble, no increased RV impulse
  • Decreased on inspiration/sitting/standing

Innocent Pulmonary Branch Murmur of Infancy
  • Systolic ejection murmur from turbulence in pulmonary artery branches (one or both)
  • Medium pitch
  • Physiologic in neonates, becoming audible at L,R,B USB between 0-2wks
  • Transmits well to back and axilla. common in premature; disappears early in infancy
  • Not PS- no ejection click, no increase in RV impulse

Supraclavicular Bruit
  • Systolic ejection murmur of medium pitch from physiologic turbulence of carotid/subclavian and heard at base of neck
  • Can be palpable. Disappears on hyperextension of shoulders
  • Not AS which is loudest at URSB with systolic thrill, sometimes with click

Venous Hum
  • Continuous murmur from turbulent flow in SVC heard at L,R,or B infraclavicular position while sitting/standing
  • Not PDA (bounding pulse, systolic>diastolic sound) or AV malformation
  • Disappears in recumbent position, rotation of head, by pressure at jugular

Mammary Souffle
  • Blood flow in A and V to engorged breast
  • Systolic or continuous, disappears with stethoscope pressure

Cardiorespiratory murmur
  • High pitched cooing, anywhere, but especially apex
  • Breath sound so not timed to heart, disappear when holding breath

Management

See Also
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