POTD: Retropharyngeal Abscess

This POTD is inspired by a case I had this weekend. This is a rare but very important diagnosis that we cannot miss. The patient was in her 30s with history of ESRD, DM, HTN, and psychiatric disorders who was transferred to us from an outside hospital. She initially presented to the ED with unilateral neck pain and swelling which quickly progressed to difficulty swallowing. She had a CT scan done at the outside hospital without IV contrast and was transferred to us for higher level of care. The patient on exam was well appearing, non-toxic, tolerating her secretions and protecting her airway. There was obvious unilateral neck swelling and tenderness. There is no exudates or erythema of the pharynx on examination. Now lets talk about retropharyngeal abscess and then we will return to my case.

 

Background:

·      Most commonly occurs in children under the age of 5 because children have more retropharyngeal lymph nodes

o   Typically child will have URI which leads to a suppurative cervical lymphadenitis leading to a retropharyngeal abscess

·      When it occurs in adults most commonly caused by posterior pharynx trauma that introduces bacteria to the retropharyngeal space that leads to phlegmon or abscess. Also commonly occurs in patients that are in an immunocompromised state

·      Most common complication is airway obstruction leading to asphyxiation

·      In adults more likely to extend into the mediastinum compared with children

 

Important Differential Diagnosis to Consider for Patients with Sore Throats:

·      Severe Life Threatening

o   Ludwig angina

o   Peritonsillar abscess

o   Retropharyngeal abscess

o   Epiglottitis

o   Bacterial Tracheitis

o   Meningitis

o   Lemierre syndrome (infectious thrombophlebitis of the internal jugular vein

o   Tumor

o   Foreign Body

o   Oropharyngeal trauma

·      Easily treatable

o   Bacterial pharyngitis

o   Viral pharyngitis

o   Mononucleosis

 

Signs/Symptoms:

·      Fever

·      Sore throat, Dysphagia, Odynophagia

·      Drooling, muffled voice, dysphonia

·      Neck stiffness

 

Physical Exam Findings:

·      Pain/limitation of neck extension/flexion

·      Fever

·      Cervical lymphadenopathy

·      Trismus, Torticollis

·      Diffuse edema and erythema of posterior pharynx

·      Neck swelling (rare)

·      Tracheal rock sign (pain with movement of trachea from side to side)

·      Symptoms disproportionate to exam findings

·      Concerning PE Findings that may prompt need for intubation

o   Stridor, tachypnea, retractions

o   Unable to handle secretions

o   Positioning (sniffing, neck in hyperextension)

o   Voice changes

 

Diagnostics:

·      Should obtain CBC, Blood cultures, +/- ESR and CRP

·      Can start with lateral neck x-ray

o   AP diameter of soft tissues along anterior bodies of C1-C4 should be less than 40% of the AP diameter of the vertebral body behind it anything greater is suggestive of soft tissue swelling which can be consistent with an abscess and should guide you to get a CT

§  Normal measurements in adults (normal increases as you go down each vertebral level)

·      At the level of C2 should measure < 6-7mm (all ages

·      At the level of C6 should measure less than 14mm in children and  < 22mm in adults

o   You may also see foci of gas which would appear as black spots within the soft tissue which is very concerning for infection caused by gas-producing bacteria similar as to what we see with necrotizing fasciitis

·      Most definitive modality is CT neck with IV contrast

o   CT will also allow you to determine if there is involvement of the carotid sheath and the mediastinum which you would not be able to do with plane film

Microbiology:

·      Most infections are polymicrobial

o   Streptococcus pyogenes

o   Staphylococcus aureus

o   Fusobacterium

o   Haemophilus

o   Other respiratory anaerobic organisms

 

Management:

·      Antibiotics

o   Clindamycin 600-900mg TID

o   Unasyn 3g IV

o   Cefoxitin 2g IV

·      ENT consult

o   Typically abscesses greater than 2cm will require OR for I&D while smaller than that can be treated with IV antibiotics and monitored

·      If intubation is required preferred method is fiberoptic to avoid rupturing the abscess

·      Decadron for symptoms relif

·      Iburpofen, Tyelnol, Toradol, or Morphine for pain control depending on pain scale

·      Admission

o   Preferably ICU for airway monitoring

 

Our patient ended up getting a CT scan with IV contrast which showed early signs of abscess formation. ENT was consulted and patient was admitted to medicine for IV antibiotics and monitoring. During the admission thoracic surgery was consulted as the CT showed extension to the thoracic cavity with concern for mediastinditis.

 

An important point in our case was also that we need to remember that ESRD patients that are already dependent on hemodialysis can get IV contrast. It is important to coordinate with the nephrology service for the next dialysis session. Some patients will need dialysis urgently after receiving the contrast dose and others could wait for their next scheduled session. Our patient was radiated twice which is unfortunate because the outside hospital was concerned about using contrast as the patient was an ESRD patient.

 

References:

·      http://www.emdocs.net/elemental-em-retropharyngeal-abscess/

·      https://myemresidency.wordpress.com/2017/11/03/retropharyngeal-abscess-in-an-adult/

·      https://accessemergencymedicine.mhmedical.com/content.aspx?bookid=2969&sectionid=250460428

·      https://wikem.org/wiki/Retropharyngeal_abscess

 

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