This is an 8 month old male who was in his usual 
state of health until 2 weeks ago when he developed 
fever (38 to 39 degrees C), intermittent cough, 
congestion, and increased secretions.  He was treated 
with antibiotics by his primary care physician.  One 
week ago, he developed hives with wheezing, stridor 
and tachypnea.  He was treated with albuterol and 
prednisolone with subsequent relief.  Three days ago, 
he then developed a dry cough, shallow respirations, 
and apparent stiffness of his neck with an inability to 
straighten his neck or bring his head to midline.  He 
was most comfortable in the position of being upright or 
lying on his side.  Gradually, his respirations became 
"noisy and gurgly".  He now presents to a rural 
emergency department with worsening stridor.  His past 
medical history is unremarkable.
     Exam:  VS T39, P120, R40, oxygen saturation 
98-100% on RA.  He is somewhat irritable but easily 
arousable and consolable, holding his neck in a solitary 
position.  Eyes normal.  Nares are clear without 
drainage.  Tympanic membranes normal.  His oral 
cavity is clear, with moist mucosa.  The posterior 
pharynx is very full, with slightly enlarged tonsils 
bilaterally.  His neck is slightly stiff with discomfort 
experienced on movement.  There is right-sided 
cervical lymphadenopathy, with slight tracheal 
deviation to the right.  Breath sounds demonstrate 
moderate stridor with slight coarse rhonchi.  Heart 
regular rate and rhythm, without murmur.  Abdomen is 
soft and flat, normal bowel sounds, no organomegaly.  
His extremities are warm with normal capillary refill.  
His skin demonstrates no rashes or lesions.
     Radiographs of his chest and neck are ordered.  
Can you identify the abnormalities on his radiographs.

View his chest and lateral neck radiographs.

His chest radiographs


His lateral neck radiograph



     His lateral neck radiograph shows severe 
prevertebral soft tissue swelling with extension 
inferiorly.  The width of the prevertebral soft tissue 
should normally be about half the width of a vertebral 
body (see Case 10 of Volume 1).  In this case, it is very 
wide.  His chest radiograph demonstrates a widened 
mediastinum and shift of the airway to the right.
     He is intubated using rapid sequence intubation to 
ensure a stable airway during air transport to a 
children's hospital for further management.  A CT scan 
of the chest is obtained prior to transport.

View his chest CT scan. 


Scout view showing image cut levels


     The CT scan demonstrates a retropharyngeal 
abscess that extends towards the posterior 
mediastinum to the level of the aortic arch.  This image 
shows the abscess (black arrows) on cuts 8, 11, 14, 17 
and 19 from his CT study.  The level of these cuts are 
demonstrated on the scout view.  At a level 
through his mouth, cut 8 shows the large abscess 
cavity which bulges anteriorly.  At chin level, cut 11 
shows the abscess with a typical  enhancing rim.  Cut 
14 shows the abscess at mid-neck level.  Cut 17 shows 
extension of the abscess into the mediastinum at the 
level of the lung apices.  Cut 19 shows extension of the 
abscess into the mediastinum at the level of the upper 
lobes.
     He was initially placed on clindamycin and 
cefotaxime.  He underwent a surgical drainage 
procedure for both the retropharyngeal and mediastinal 
abscesses.  Cultures of the pus grew Group A beta 
hemolytic streptococci, at which time he was changed 
to penicillin.  
  
Discussion 
     The retropharyngeal space is a potential space in 
the deep neck that is bordered by the buccopharyngeal 
fascia anteriorly, the prevertebral fascia posteriorly, 
and the carotid sheath laterally.  An infection 
developing in this space could potentially spread into 
the mediastinum and other deep neck compartments.  
In the pediatric population, this space contains lymph 
nodes draining the nasopharynx, paranasal sinuses, 
nasal cavity, and soft palate.  These retropharyngeal 
nodes atrophy at puberty making abscess formation 
less likely in teens and adults.
     Retropharyngeal abscesses are most commonly 
present in children less than 3 years of age.  In the 
pediatric population, retropharyngeal abscesses 
typically result from upper respiratory infections 
(particularly oropharyngeal infections) with suppurative 
cervical lymphadenopathy, whereas in adults they 
normally occur secondary to trauma to the oropharynx, 
iatrogenic instrumentation, foreign bodies, or dental 
infections.
      Initial antimicrobial empiric therapy is directed 
towards the aerobic and anaerobic flora of the 
nasopharynx.  Common aerobes are Staphylococcus 
aureas, alpha hemolytic and non-hemolytic 
streptococci, Haemophilus species, and group A 
beta-hemolytic Streptococci.  Common anaerobes are 
bacteriodes, peptostreptococci, and fusobacteria.  
During surgical drainage, an aspirate of the pus is 
obtained for specific determination of the causative 
microorganism(s).
     Signs and symptoms include high fever, dysphagia, 
odynophagia, drooling, neck/cervical rigidity and 
swelling, anorexia, a "hot potato"/muffled voice, 
bulging/fluctuance of the posterior pharyngeal wall 
which is usually difficult to see.  Dysphagia and 
drooling are more common indicators of actual upper 
airway involvement, whereas inspiratory stridor is less 
common.
     When suspected clinically, a lateral neck radiograph 
is usually adequate to diagnose the presence of a 
retropharyngeal abscess.  A true lateral neck x-ray 
should be taken in extension (cervical spine lordosis 
should be visible on the radiograph) and inspiration.  
The anteroposterior diameter of the prevertebral soft 
tissues should not exceed the width of the vertebral 
bodies.  With a retropharyngeal abscess, a classic 
widened soft tissue shadow anterior to the cervical 
vertebrae is seen with a normal epiglottis and 
aryepiglottic folds.
     A CT scan is diagnostically useful to distinguish 
between abscess (requiring surgical drainage) and a 
phlegmon cellulitis (which may not require surgical 
drainage), indicating the extent of abscess involvement, 
localizing the lesion prior to surgical intervention, and 
to differentiate which deep neck spaces are involved 
(see Case 1 of Volume 5).  
     Retropharyngeal abscess is in the differential 
diagnosis of a febrile infant with airway obstruction.  
Usually a high index of suspicion is needed to identify a 
child with a retropharyngeal abscess.  The presentation 
of a stiff neck can initially be misdiagnosed as 
meningitis, and inspiratory stridor may mimic croup or 
epiglottitis.
     Treatment of a retropharyngeal abscess requiers 
the maintainance of a stable airway, thus, endotracheal 
intubation may be necessary if airway compromise is 
present.  IV antibiotics are required.  Surgical drainage 
is usually required in a true abscess.  Perioral drainage 
is normally adequate for uncomplicated infections that 
have not entered other deep neck spaces or affected 
the airway.  External drainage, along the anterior 
aspect of the sternocleidomastoid, between the carotid 
sheath and inferior constrictor muscle, is usually 
required for the more severe infections that have 
spread to other compartments.  Antibiotics should 
initially cover the common microbes (i.e. streptococci, 
staph aureus, anaerobes).
     Complications include mediastinitis and mediastinal 
abscess secondary to spread from the retropharyngeal 
space (being contiguous with the mediastinum), airway 
obstruction, and rupture of the abscess with potential 
aspiration of pus and pneumonia.  Mediastinitis is a 
rare and life-threatening complication with a mortality 
rate as high as 40%.  Most cases of reported 
suppurative mediastinitis have been secondary to 
esophageal perforation (traumatic or nontraumatic) and 
after median sternotomy. 
     When managing a patient with a retropharyngeal 
abscess, physicians should consider the possibility of 
this complication.  Chest radiographs may be 
necessary to rule out mediastinal or pulmonary 
involvement.  A CT scan will also be helpful in 
determining the extent of the abscess.  The extension 
of the infection of the neck to the mediastinum has 
been attributed to synergistic necrotizing bacterial 
growth, negative intrathoracic pressure, and dependent 
drainage from the neck to the mediastinum.  The high 
occurrence of mixed aerobic and anaerobic flora in 
retropharyngeal abscess complicated by mediastinitis 
may account for the necrotizing nature of this type of 
infection.  Immediate diagnosis and surgical drainage 
of the retropharyngeal and mediastinal abscesses are 
essential for treatment.  

References
     1.  Gaglani MJ, Morven SE.  Clinical Indicators of 
Childhood Retropharyngeal Abscess. Am J Emerg Med 
1995;13(3):333-335.  
     2.  Goldenerg D, Gotz A, Joachms HZ.  
Retropharyngeal Abscess: a Clinical Review.  J 
Laryngol Otol 1997;111:546-550.
     3.  Lalakea ML, Messner AH.  Retropharyngeal 
Abscess Management in Children: Current Practices.  
Otolaryngol Head Neck Surg 1999;121(4):398-405.
     4.  Sztajnbok J, Grassi MS, Katayama DM, Troster 
EJ.  Descending Suppurative Mediastinitis: Nonsurgical 
Approach to this Unusual Complication of 
Retropharyngeal Abscesses in Childhood.  Pediatr 
Emerg Care 1999;15(5):341-343.