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
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