This is a 23-month old female with a history of 
vomiting 3-4 times per day for three days.  She has a 
past history of reactive airway disease and congenital 
heart block (maternal systemic lupus) requiring a 
permanent implanted pacemaker.  She was seen three 
days prior to this in the emergency department for 
wheezing and stomach pain.  She was noted to have 
bilateral wheezing.  Her respiratory rate was 32.  An 
oxygen saturation was not recorded.  Her abdominal 
exam was benign.  The wheezing was treated with beta 
adrenergic agents resulting in improvement, and the 
patient was discharged.  At discharge, her lungs were 
noted to be clear.  She was instructed to continue 
albuterol and theophylline.
     Since that visit, she began vomiting.  She was seen 
by her pediatrician today, who placed her on amoxicillin 
for otitis media.  Her mother called her pediatrician, 
noting the child was more fussy, lethargic, and her 
mouth appeared to be dry.  She was referred to the 
hospital for inpatient rehydration.
     Admission exam:  VS T36.6 (ax), P110, R32, BP 
112/70, weight 10.1kg (10th percentile).  Her weight 
three days ago in the ED was 10.66kg.  Oxygen 
saturation was 98-99% in room air.  She was noted to 
be crying, but somewhat lethargic.  HEENT exam 
significant for somewhat sunken eyes, dry oral mucosa, 
and absence of tears when crying.  Neck supple.  Heart 
regular without murmurs.  Lungs clear with decreased 
breath sounds at the left base.  No wheezing was 
noted.  There was a left thoracotomy scar and a left 
subcostal scar.  Abdomen noted to have a palpable 
pacemaker in the left anterior abdominal wall and a 
reducible umbilical hernia.  The abdomen was flat and 
soft without masses, organomegaly, or tenderness.  
Bowel sounds were active.  Capillary refill time in the 
extremities was two seconds and the skin turgor was 
good.
     An admission work-up included the following 
laboratory results:  CBC  WBC 8.9, 56 segs, 32 lymphs, 
12 monos, Hgb. 12, Hct 38, platelets adequate.  Na 
132, K 4.2, Cl 100, Bicarb 21, BUN 14, Cr 0.7, glucose 
94.  A chest radiograph was obtained.

View CXR


     This CXR demonstrates a pacemaker wire and air 
in the left chest with a tracheal shift to the right.  This 
was not felt to be a pneumothorax, but rather an 
intrapulmonary pneumatocele.  An upper GI series was 
performed, which showed the stomach to be in the 
normal position below the left hemidiaphragm.  There 
was also paradoxical motion of her left hemidiaphragm 
noted.  This was felt to be due to phrenic nerve injury 
during her pacemaker implantation.  She developed 
worsening abdominal pain that night.  Early the next 
morning, abdominal distention and worsening 
tenderness were noted.  She was thought to have an 
acute abdomen.  A follow-up abdominal series showed 
a bowel obstruction pattern and a barium filled colon in 
the left side of the chest, indicating a diaphragmatic 
hernia.  She was taken to surgery where a left 
diaphragmatic hernia was noted.  Colon and spleen 
were noted to be in the left hemithorax.  A small 
volvulus was noted.  A successful repair was 
performed.

Teaching Points and Discussion
     Large pockets of air in the chest do not always 
represent a pneumothorax.  This can be extremely 
deceiving at times since large air pockets will often 
have signs and symptoms similar to a tension 
pneumothorax.  Respiratory distress, diminished breath 
sounds, and a mediastinal shift may all be present.  A 
classic example of this is a diaphragmatic rupture 
following trauma to the chest or abdomen.  Crying, 
hyperventilation, or mask ventilation may increase the 
degree of air in the bowel, distending it further, resulting 
in expanding air pockets in the chest.  The bowel may 
be so distended at times, that an initial chest radiograph 
may have difficulty distinguishing this from a 
pneumothorax.  It is often taught that thoracentesis or 
chest tube thoracostomy should not wait for a CXR if a 
tension pneumothorax is suspected.  If a tension 
pneumothorax is present, air evacuation would result in 
immediate improvement in the patient's status; 
however, with a ruptured diaphragm, such a procedure 
would not result in any improvement.
     Diaphragmatic hernia is usually a diagnosis made at 
birth; however, the diaphragmatic defect can be small 
such that the herniation of abdominal contents occurs 
later in life similar to an inguinal hernia.  Although an 
upper GI series will usually show the stomach to be in 
the left chest, less frequently, the stomach will remain in 
the abdomen while distal bowel is found in the chest
instead.
     Congenital lobar emphysema can also present with 
findings mimicking a tension pneumothorax.  The 
emphysematous lobe may be so distended that 
appreciating any lung markings may be difficult. 
     Cystic malformations of the lung or pneumatoceles 
may also resemble air leak syndromes.
     It is possible that thoracentesis or chest tube 
thoracostomy will result in complications if performed in 
any of the above conditions.  In addition, such 
procedures are not helpful in these conditions.  
Although a metal trochar is included with most chest 
tubes, it is not advisable to use these.  The trochar is 
more likely to cause injury to lung and bowel, if one of 
the above conditions is present instead of a 
pneumothorax.  In all conditions, the trochar is more 
likely to injure one of the great vessels.  It is preferable 
to insert the chest tube without the trochar, thereby 
substantially reducing the risk of complications.

References
     Templeton JM.  Thoracic Emergencies.  In:  Fleisher 
GR, Ludwig S.  Textbook of Pediatric Emergencies, 
third edition.  Baltimore, Williams & Wilkins, 1993, pp. 
1336-1362.