Tachypnea and Abdominal Pain
Radiology Cases in Pediatric Emergency Medicine
Volume 2, Case 5
Loren G. Yamamoto, MD, MPH
Lynette L. Young, MD
Kapiolani Medical Center For Women And Children
University of Hawaii John A. Burns School of Medicine
     This is a 6 year old male who was referred from a 
rural ED for fever and possible pneumonia.  He was 
well until three days ago when he was stung by a bee 
on his right forearm.  He developed a moderate local 
reaction with edema and erythema.  He saw his primary 
care physician the next day at which time he also 
complained of chest pain.  Chest radiographs were 
obtained that day and they were negative.  The next 
evening (yesterday), he developed fever and worsening 
of the swelling and erythema of his right forearm.  He 
was seen at a rural ED.  Cellulitis and a hypersensitivity 
reaction were considered.  He was placed on oral 
cephalexin and acetaminophen with codeine.  He took 
two doses of cephalexin.  He returned to the rural ED in 
the morning (today) because of abdominal pain.  Chest 
radiographs were repeated.  This was interpreted as 
showing a possible right lower lobe infiltrate.  A CBC at 
that time showed:  WBC 20.4, 67% segs and 18% 
     Exam on arrival:  VS T38.5 (oral), P145, R44, BP 
140/89, oxygen saturation 96% (room air).  He was 
obese, crying, agitated, and uncooperative, making 
examination difficult.  HEENT exam significant for 
slightly dry oral mucosa.  Neck supple.  Heart regular, 
tachycardic, without murmurs or gallops.  Lungs coarse 
breath sounds with rhonchi in both bases.  Abdominal 
guarding noted throughout with tenderness.  Bowel 
sounds were hypoactive.  His right arm was diffusely 
indurated and erythematous (difficult to distinguish 
cellulitis from hypersensitivity).
     He was given a fleets enema for suspected 
constipation.  He passed large amounts of stool and 
seemed to be better in that he was less agitated and 
more cooperative.  He was noted to be grunting at 
times.  His abdomen was still tender.  More blood 
studies were drawn.  Radiographs of his chest and 
abdomen were obtained.

View CXR:  PA view.

View CXR:  Lateral view.

View Abdominal Series:  Upright view.

View Abdominal Series:  Supine view.

     Although there some subtle abnormalities on his 
CXR, there were no definite abnormalities to account 
for his grunting and abdominal pain.  There were some 
possible central infiltrates and the right hemidiaphragm 
appeared to be possibly elevated.  The inspiratory effort 
shown on the film was poor.  This was also noted on 
the CXR from the rural ED.  His abdominal radiographs 
showed some bowel distention, but consistent with an 
ileus and not a bowel obstruction.
     Laboratory results:  CBC  WBC 33.6, 1 meta, 29 
bands, 63 segs, 5 lymphs, 2 monos, Hgb 13.1, Hct 
39.0, platelet count 310,000.  Na 136, K 4.0, Cl 102, 
Bicarb 21, glucose 142.  UA SG 1.031, 0-2 WBC, 
3-5 RBC.
     An abdominal ultrasound was performed looking for 
an intra-abdominal abscess.  This study showed a 
suspicious right lower quadrant mass, but it was unable 
to define it further.  A surgical consultation was 
obtained.  The likelihood of acute appendicitis was felt 
to be low.  A CT scan of the abdomen was obtained.  
This study was unremarkable except for a view of the 
upper abdomen.

View CT scan.

     This CT cut is through the upper abdomen.  It shows 
the liver, parts of the diaphragm, and the lower portions 
of the lungs.  Pulmonary infiltrates are noted in the 
posterior portion of the right lower lobe.  Note the 
pleural effusion adjacent to the infiltrates (arrows).  He 
was given IV ceftriaxone and hospitalization was 
     Six hours after leaving the ED, house officers 
ordered a follow-up CXR (13 hours after the ED CXR, 
and 8 hours after the CT scan).

View follow-up CXR.

     This CXR shows a large right pleural effusion.  This 
is a significant change over the 13 hour period since the 
previous CXR suggesting a rapidly progressive 
pneumonia.  This is highly suspicious for a 
staphylococcal pneumonia.  The source of the staph 
was suspected to be the cellulitis on his arm.  The 
pleural effusion worsened, at which time it was drained 
through a tube thoracostomy.  Gram stain of the fluid 
revealed gram positive cocci.  Cell counts 50,000 
RBC's, 29,000 WBC's, 70% segs, 18% bands.  Protein 
5.4 grams/dl, pH 7.0, glucose 8 mg/dl.  He required a 
second chest tube to drain a loculated empyema.  
Other than this, he did remarkably well.  He did not 
develop any pneumatoceles or a pneumothorax.  He 
was discharged after 6 weeks of IV antibiotics.

Teaching Points and Discussion
     Staphylococcal pneumonia is rapidly progressive in 
all age groups.  This is a serious pulmonary infection 
that is associated with significant morbidity and a high 
potential for death.
     There are two main forms of staphylococcal 
pneumonia.  Primary pneumonia is caused by direct 
inoculation through the respiratory tract.  Secondary or 
metastatic hematogenous lung infection is due to 
bacteremic seeding of the lung during the course of 
endocarditis or septicemia associated with infection at 
other sites.  It is not unusual to see severe impetigo 
associated with staphylococcal pneumonia.
     Primary staphylococcal pneumonia is a disease of 
infancy and childhood with three-quarters of the cases 
involving patients less than one-year old.  Predisposing 
factors include cystic fibrosis, chronic lung disease, 
leukemia, preexisting skin infection, and viral respiratory 
infection (measles, influenza, adenovirus).
     The patients with staphylococcal pneumonia may 
present with fever, lethargy, severe respiratory distress 
(tachypnea, grunting, retractions, cyanosis), and 
gastrointestinal disturbances (anorexia, vomiting, 
abdominal distention).  About 75% of patients present 
with fever, cough, and dyspnea.  The rapid progression 
of clinical symptoms is characteristic of staphylococcal 
     Chest radiographs in the early stage of 
staphylococcal pneumonia may be normal or show a 
minimal focal infiltrate.  In general, there is a rapid 
progression of radiographic findings over just a few 
hours.  The segmental bronchopneumonia pattern is 
usually unilateral and then expands to involve other 
lobes.  In the case of our patient here, he presented 
with abdominal pain and tachypnea.  A small infiltrate 
was noted which progressed to a large pleural effusion 
over a few hours.
     About 71% of pneumonias due to Staph aureus 
have associated pleural effusions.  The effusion is on 
the right in 65%, on the left in 15% and bilateral 20% of 
the time.  This frequently progresses to an empyema.  
Ultrasound or CT is often helpful in locating the 
loculated fluid.
     A pulmonary pneumatocele is a frequent 
complication of staphylococcal pneumonia with an 
incidence of greater than 85%.  There are usually 
multiple pneumatoceles which vary in size.  
Pneumatoceles are believed to be caused by a partial 
airway obstruction by intraluminal exudate or a 
peribronchial abscess.
     A lung abscess is another complication of 
staphylococcal pneumonia.  An abscess is a relatively 
thick-walled cavity, in contrast to a pneumatocele which 
is usually a thin-walled radiolucent area.  Fluid levels 
may be present in both pneumatoceles and abscesses.
     The incidence of pneumothorax associated with 
staphylococcal pneumonia is between 40% to 60%. A 
pneumothorax may result from a pneumatocele rupture 
or formation of a bronchopleural fistula (localized 
bronchial wall necrosis).  A pyopneumothorax 
(pneumothorax + empyema) is highly suggestive of 
staphylococcal pneumonia.
     Empyemas require drainage with large bore tube 
thoracostomies.  The empyema is often rapidly 
progressive, which leads to compression of the lung 
and respiratory failure unless the empyema is drained.  
It is likely to reaccumulate following a thoracentesis.  
Chest tube thoracostomy also has the benefit of 
maintaining lung expansion if a pneumothorax 
     A pathogen is recovered from patients with 
pneumonia and effusions about 76% of the time.  Of 
these, pleural fluid cultures are positive  in 86% and 
blood cultures are positive in 10%.
     Although antibiotic coverage with anti-staphylococcal 
penicillins (e.g., oxacillin) or first generation 
cephalosporins (e.g.. cefazolin) is usually sufficient, 
there is a substantial rate of resistance to these drugs.  
Methicillin resistant staph aureus will usually be 
cephalosporin resistant as well.  Vancomycin should be 
added to the anti-staphylococcal antibiotic regimen until 
sensitivities of the organism are determined.  
     Complications of staphylococcal pneumonia include 
endocarditis, purulent pericarditis, osteomyelitis, deep 
tissue abscess, septic arthritis, and meningitis.

     Chartrand SA,  McCracken GH.  Staphylococcal 
pneumonia in infants and children.  Ped Infect Dis
     Forbes GB, Emerson GL.  Staphylococcal 
pneumonia and empyema.  Pediat Clin N Amer 
     Melish ME.  Staphylococcal Infections.  In:  Feigin 
RD, Cherry JD (eds).  Textbook of Pediatric Infectious 
Diseases, 2nd edition, 1987, Philadelphia, WB 
Saunders Company, pp. 1260-1292.

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