22yM bounces back 3 days after an ED fishbone extraction with fever and sore throat. His neck is rigid in extension.
The retropharyngeal space is between the posterior pharynx and the prevertebral space (see picture). You can feel a mass and elicit tenderness by rocking the trachea side-to-side (tracheal rock sign). Other symptoms - neck stiffness and pain, dysphagia, "duck-like" voice (cri du canard).
Three ways to get an RPA-
1- Suppuration of lymph nodes from local infection (pharyngitis, etc), MCC in children and the majority of cases
2- Direct penetration from trauma (fishbone, EGD)
3- Extension of local purulence from vertebral osteomyelitis, Ludwig's
You will get a CT w/contrast on these patients, but a quicker diagnosis can be obtained with a lateral soft tissue neck x-ray during inspiration and slight neck extension. There will be a widened retropharyngeal space at C2-C4. Or do an ultrasound!!!
Treatment, like always, starts with the airway. Think about fiberoptic intubation to avoid abscess rupture. Then, order IV abx for mixed flora (clinda, cefoxitin, unasyn) and consult ENT for I&D.
Sources
Rosh Review
Clinical Gate: Airway imaging
WikiEM: RPA
Pediatric EM Morsels: RPA3
Medbullets: RPA