Tachypnea in a 2-Month Old
Radiology Cases in Pediatric Emergency Medicine
Volume 4, Case 3
James J. Matsuda MD, PhD
Kapiolani Medical Center For Women And Children
University of Hawaii John A. Burns School of Medicine
     This is 2-month old male who presents to the 
emergency department with a five day history of funny 
breathing.  He was well until 5 days prior when his 
mother noted noisy, rapid breathing and a tactile 
temperature.  Four days prior, he was taken to his 
private physician and was started on amoxicillin for 
otitis media.  His lung exam at that time was normal.  
Two days prior he was taken to the emergency 
department and was noted to be wheezing.  He was 
given an albuterol aerosol and was discharged on oral 
albuterol.  He continued to have breathing problems at 
home and now returns to the emergency department 
since his condition has not improved.
     His birth history is unremarkable, and he has shown 
adequate weight gain since birth.  There are no 
reported feeding problems according to his mother.  His 
family history is significant for two siblings with asthma.
     Exam:  T36.9, P168, BP 98/60.  His respiratory rate 
varies between 60 and 80 per minute.  His oxygen 
saturation is 97% in room air.  His oxygen saturation 
improves to 100% on oxygen by nasal cannula at 2 
liters per minute.  He is a fussy infant with modest 
tachypnea.  Despite this, he does not appear to be in 
significant distress.  He is not toxic.  He is noted to 
have mild retractions when crying, with bilaterally 
coarse breath sounds without wheezes.  Heart regular 
without murmurs or gallops.  Abdomen:  Liver edge 
palpable 3 cm below the right costal margin.
     A chest X-ray is obtained.

View CXR:  AP view.

View CXR:  Lateral view.

     Do you think this represents a pneumonia?  The 
emergency department physician reads this as mild 
perihilar infiltrates.  A diagnostic impression of a viral 
pneumonia is made, and the infant is hospitalized 
because of his young age and persistent tachypnea.
     The following morning, the radiologist reads the 
chest radiograph as showing borderline cardiomegaly 
with prominence of the right atrium and increased 
pulmonary vascularity.  The right heart border appears 
to be prominent, but this initially was thought to be due 
to rotational artifact.  The diffuse reticular markings 
fanning out from the hilum suggest pulmonary venous 
congestion but are difficult to distinguish from perihilar 
infiltrates. These findings are suggestive of congenital 
heart disease.  This radiographic information prompts a 
cardiac work-up.  The most important point here is to 
realize that a cardiac defect may be responsible for the 
infant's respiratory symptoms.  Scrutinizing the chest 
radiograph for subtle signs of cardiac disease is 
important since, once cardiac disease is suspected, it is 
a simple matter of obtaining an echocardiogram.
     After admission to the wards, the infant develops 
worsening respiratory distress.  A blood gas is obtained.  
On room air, an arterial blood gas shows pH 7.27, 
pCO2 35, pO2 76, HCO3 of 16.  With 100% O2, the 
pO2 increases to 138.  An EKG shows right atrial 
enlargement with right axis deviation and right 
ventricular hypertrophy.  An echocardiogram shows a 
membranous structure in the left atrium, a high atrial 
septal defect, and dilation of the right atrium and right 
ventricle.  The right ventricular systolic pressure is 
elevated to 103 mm Hg.  The diagnosis of cor 
triatriatum with secondary congestive heart failure is 
made, and the infant is started on digoxin and diuretics.  
He is referred to a cardiac surgeon for corrective 
surgery and does well postoperatively.
     A follow up chest radiograph taken a few months 
later shows a decrease in heart size and decreased 
pulmonary congestion.

View follow-up CXR.

     Also present are surgical wires and metal clips in 
the area of the left atrium. There is some residual 
prominence of the pulmonary vasculature.
     Cor triatriatum is a rare congenital cardiac anomaly 
where the pulmonary veins enter an accessory 
chamber that joins the left atrium through a narrow 
opening.  This accessory chamber may also directly 
communicate with the right atrium.  In classical cor 
triatriatum, a membranous partition exists in the left 
atrium in the shape of a wind sock. 

View Cor Triatriatum diagram.

     The upper chamber (XC) of this partition receives 
blood from the pulmonary veins, and the distal chamber 
communicates with the mitral valve.  The orifice 
diameter of the windsock ranges from less than 3 mm 
to about 1 cm.  In a minority of cases, a patent foramen 
ovale or an atrial septal defect allows communication 
with the right atrium.  Right ventricular  hypertrophy and 
dilation are almost always present, and right atrial 
dilation occurs 25% of the time.  Current theories 
suggest that the defect occurs because the common 
pulmonary vein fails to incorporate into the left atrium 
during cardiac embryogenesis.
     The clinical features of this anomaly are related to 
the pulmonary congestion and hypertension created by 
the membranous left atrial structure.  When pulmonary 
venous blood flow becomes obstructed, the lungs 
reflect varying degrees of pulmonary edema and 
intraalveolar hemorrhage.  Patients usually present 
within the first few years of  life with a history of 
shortness of breath and frequent pulmonary infections 
and audible rales.  Signs of pulmonary hypertension, 
including a loud pulmonic component of the second 
heart sound, right ventricular heave and pulmonary 
systolic ejection clicks are often present.  The usual 
heart murmur is a soft, blowing, systolic murmur heard 
best at the left sternal border.  The EKG usually reveals 
signs of right-sided heart overload such as right 
ventricular hypertrophy and right atrial enlargement.
     The chest radiograph often reveals pulmonary 
venous obstruction.  Diffuse reticular pulmonary 
markings fan out from the hilum to involve the lower 
lung fields.  Kerley B lines may also be present.  The 
right heart border may reveal a double density 
suggestive of left atrial enlargement.  Other findings 
include enlargement of the main pulmonary artery and 
right ventricular hypertrophy.
     Treatment of this disease involves management of 
congestive heart failure.  Once patients reach this 
stage, they usually deteriorate fairly quickly despite 
medical management.  Surgical intervention should be 
planned as soon as possible in symptomatic patients 
once the diagnosis is made.  The operation of choice is 
usually correction under direct vision with 
cardiopulmonary bypass.  The prognosis of cor 
triatriatum is related to the size of the orifice in the 
obstructing membrane.  Without surgical correction, the 
average survival is about 3 months when the opening is 
less than 3 mm, and 16 years when the opening is 
greater than 3 mm.  In those patients surviving 
operative correction, the prognosis is excellent.

     Adams FH, Emmanouilides GC, Riemenschneider 
TA.  Moss' Heart Disease in Infants, Children and  
Adolescents, 5th edition.  Baltimore, Williams and 
Wilkins Co, 1989, pp. 863-868.
     Ramaswamy P, Friedman DM, Long S.  Images in 
cardiovascular medicine. Noninvasive diagnosis of cor 
triatriatum.  Circulation 1995;92(4):1058-1059.

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Web Page Author:
Loren Yamamoto, MD, MPH
Associate Professor of Pediatrics
University of Hawaii John A. Burns School of Medicine