A two and one-half week old male infant presents 
with a history of distressed noisy breathing for several 
hours, progressively worsening with periods of apnea 
and cyanosis.  He had appeared well all day at the 
baby-sitter's until one hour after his last feeding when 
he was found to have the symptoms of respiratory 
distress.  He had no history of fever, URI symptoms, 
vomiting, or diarrhea.  No possible exposure to toxins or 
foreign bodies could be found.  Birth history was that of 
a full term, NSVD, 7lb. 8oz. born to a 23 y/o G3P2 
mother without sepsis risk factors.  He seemed to be 
doing well since discharge but had been noted by his 
parents to have "funny breathing" since birth.  This was 
described as periodic rapid breathing with "deep caving" 
in of his anterior chest.  It did not cause cyanosis, nor 
did it interfere with feeding.  Weight gain since birth has 
been appropriate.
     Exam VS T36.7, P160, R60, BP 100/70.  Oxygen 
saturation 86% in room air.  He was alert and anxious, 
with obvious tachypnea and retractions.  Skin color was 
intermittently dusky until oxygen was administered and 
then remained pink (oxygen saturation 96-100%).  
Head atraumatic.  No signs of URI.  Neck supple.  
Suprasternal, intercostal, and subcostal retractions 
present.  Breath sounds are faint throughout the chest, 
without auscultatory rales, wheezes, or stridor heard.  
Heart sounds are distant, and no murmur is heard. 
Pulses are strong and regular.  Capillary refill is brisk.  
There are no rashes.  Abdominal, neurologic, and 
musculoskeletal exams are unremarkable.
     A CBC with differential, blood culture, electrolytes, 
glucose, UA and CXR are obtained.  Room air ABG:  
pH 7.33, pCO2 46, pO2 43 in room air.  On oxygen by 
mask, his pO2 increased to 150.  A chest radiograph 
is obtained.

View CXR PA view.


View CXR lateral view.


     This CXR  shows hyperlucency of the left chest with 
a mediastinal/cardiac shift to the right.

Management Questions:
     This looks like left tension pneumothorax.  Should 
you perform an emergency needle thoracostomy?  
Where would you do it in a 2 1/2 week old?
     Before needling the chest (2nd intercostal space, 
midclavicular line with an 18 or 20G catheter over the 
needle) review the evidence for a tension pneumothorax.
     This infant has respiratory distress with hypoxia.  
Breath sounds were described as faint throughout the 
chest rather than unequal.  Is this consistent with a 
tension pneumothorax?
     Yes, infants with tension pneumothorax rarely have 
unequal breath sounds.  The intrathoracic volume of the 
infant's chest is so small and the mediastinum is so 
mobile that decreased ventilation due to free air 
compressing both lungs usually results in distant or faint 
breath sounds and decreased chest movement 
bilaterally, rather than the differential findings between 
the two sides seen in adults.
     This infant's circulation does not appear 
compromised clinically.  The patient was alert with good 
pulses and capillary refill.  Is this consistent with tension 
pneumothorax?
     No, the hallmark of tension pneumothorax is 
persistent hypoxia (despite supplemental oxygen) with 
circulatory compromise (hypotension and/or 
bradycardia).  The fact that this patient did not have 
impaired perfusion should make you refrain from 
needling the chest and examine the CXR more carefully.

Re-examine the CXR.


     What at first appears to be a tension pneumothorax 
may instead be severe emphysema of one or more 
lobes of the lung.  Every attempt should be made to 
visualize lung markings and the lung edge within the 
hyperlucent space.  Remember that lung markings 
may be very faint because the blood vessels are spread 
out.  Additionally, there may be reflex hypoxic 
vasoconstriction as an attempt to match VQ.  Carefully 
examining the CXR using a hot light may prevent you 
from mistakenly needling the chest and causing a 
severe complication.  There are indeed lung markings 
throughout the left chest (These are evident on the 
original film, but it was very difficult to reproduce this on 
the scanned image).  You decide to intubate the patient 
and transfer to the ICU, but the patient's condition 
worsens after intubation.  What can you do?
     If this patient's emphysema becomes life-threatening 
(which may happen rapidly if positive pressure is 
applied) the only treatment would be a lateral 
thoracotomy to allow the lung to herniate out of the 
chest.  When you call the surgeon, he/she asks if you 
are sure this is not hypoplasia of the right lung or 
a diaphragmatic hernia.  How do you support the 
diagnosis of emphysema on CXR?
     There are several parameters to assess in order to 
answer this question.  Before anything else, it is 
essential to evaluate the CXR for the presence of any 
rotation.  A rotated chest film can both mimic and 
obscure a mediastinal shift.  Evaluation of the clavicles 
is one recommended method, but is often confounded 
by irregular positioning of both clavicles.  Another useful 
method is to evaluate the horizontal length of the ribs at 
the midchest level measuring from the lateral chest to 
the center of the spine on either side.  If one side is 
longer, the patient is rotated to that side and all 
structures will appear to be falsely shifted to the same 
side.

View rotated CXR.


     This neonatal CXR is rotated, as can be determined
by looking at the location of the proximal clavicles and
the non-symmetry of the rib origins.  This gives the 
CXR the appearance of left sided hyperexpansion with 
the heart pushed over to the right; however, this 
appearance is purely due to rotational artifact.
     Once the degree, if any, of rotation has been 
determined, several other areas should be evaluated.  
The bony thorax may show increased space between 
the ribs on one side, indicative of emphysema or 
pneumothorax.  The diaphragms should be evaluated 
for position and evidence of compression or elevation.  
A flattened (compressed) hemidiaphragm implies 
emphysema of an adjacent lobe or tension 
pneumothorax.  An elevated hemidiaphragm implies 
volume loss in that hemithorax due to atelectasis, 
hypoplasia or a diaphragmatic hernia.  A decubitus film 
can demonstrate failure of the emphysematous lobe to 
deflate when placed down.  Fluid in the hemithorax will 
displace the heart, but would appear radiopaque.

View patient's CXR again.


Our patient's CXR shows:
     1.  Hyperexpanded left "lung" (actually the left upper 
lobe) that herniates into the right chest.
     2.  Spreading of ribs of the left chest.
     3.  Shift of the mediastinum to the right.
     4.  Compression of the left hemidiaphragm.
     5.  Left lower lobe atelectasis (It is so small, that you 
can hardly see it.  It is largely obscured.) visible in the 
left inferior medial chest.
     6.  Normal position of the right hemidiaphragm.
     7.  No infiltrates or fluid.
     8.  All these findings are consistent with emphysema 
of the left upper lobe.

Discussion
     An important aspect of pediatric emergency care is 
to be aware of congenital anomalies and the manner 
and timing with which they present.  The differential 
diagnosis of any acute medical presentation in the first 
few months of life must include congenital problems.  
Within the first weeks of life, respiratory and cardiac 
problems often present precipitously.
     This patient had congenital lobar emphysema of the 
left upper lobe and was also found to have a patent 
ductus arteriosus.  The history suggests mild symptoms 
since birth with acute deterioration.  At lobectomy, the 
left upper lobe bronchus was noted to have 
abnormalities of the cartilage structures.   The bronchus 
was collapsed with an intraluminal mucous plug.  
Emphysema may be caused by cartilaginous 
malformation, intrinsic obstruction, or extrinsic 
compression.  This condition is most common in the 
upper lobes and associated in 10% of cases with 
congenital heart defects, most commonly patent ductus 
arteriosus.  Most cases present with respiratory distress 
within the first 4 months of life and may eventually 
require resection.  Occasionally, asymptomatic cases 
are found fortuitously on chest radiographs in later 
years.  Evaluation for coexisting congenital anomalies 
may be made through non-invasive tests such as 
echocardiography, CT, MRI, and ventilation-perfusion 
lung scan.

Additional Teaching Points:  Be Aware of . . .
     Whenever regional emphysema is present in the 
lung, suspicion of a foreign body should be very high.  
The young age of our patient made this unlikely but in 
the high-risk age group, approximately 5 months to 5 
years of age, this diagnosis must be pursued even in 
the face of a negative history.  Often bronchoscopy is 
needed to make the diagnosis and alleviate the 
condition.  Also, think of a foreign body when faced with 
cases of recurrent wheezing or pneumonia (See Case 
8 of Volume 1, Foreign Body Aspiration in a Child).
     If this infant had a true tension pneumothorax, 
staphylococcal pneumonia should be highly suspected.  
It is most common in the first six months of life and 
often has an extremely rapid onset with fever, 
tachypnea, and grunting.  Commonly, endobronchial 
infection ruptures through to the pleural space, creating 
a bronchopleural fistula early in the course of disease, 
leading to life-threatening pneumothorax and/or 
empyema.  This requires urgent placement of a chest 
tube, along with appropriate antibiotics and treatment 
for septic shock.  Staphylococcal pneumonia develops 
rapidly and initial CXR findings may show no evident 
infiltrate or only a smal amount of pleural fluid.

References
     Gerbeaux J, Couvreur J, Tournier G.  Pediatric
Respiratory Disease, second edition.  New York, J.
Wiley and Sons, 1982, pp. 217-223.
     Markowitz RI, Mercurio MR, Vahjen GA, Gross I,
Touloukian RT.  Congenital Lobar Emphysema.  
Clinical Pediatrics 1989;28(1):19-23.
     Scarpeli EM, Auld P, Goldman HS.  Pulmonary
Disease of the Fetus, Newborn, and Child.  
Philadelphia, Lea & Febiger, 1978, pp. 194-196.
     Templeton JM.  Thoracic Emergencies.  In:  Fleisher
GR, Ludwig S.  Textbook of Pediatric Emergency 
Medicine, third edition.  Baltimore, Williams & 
Wilkins, 1993, pp. 1336-1362.