Retropharyngeal abscess

Question 1

What is the definition of retropharyngeal abscess?

Answer 1

Collection of pus within the retropharyngeal space which is in between the buccopharyngeal fascia and alar fascia

Question 2

What causes retropharyngeal abscess in an adult? in children)

Answer 2

Adult

• Foreign body
• Penetrating injury to posterior pharyngeal wall/ cervical oesophagus (e.g., from small bones such as of fish or chicken; , or medical instruments)
• Contiguous spread from throat infection (oral/ URTI)

Children: Commonly caused by suppurative retropharyngeal lymph node

Question 3

What are the pathogens that cause retropharyngeal abscess?

Answer 3

• Aerobic organisms, such as beta-hemolytic streptococci (viridans Streptococci, S. pneumoniae) and Staphylococcus aureus, Haemophilus influenzae, oral anaerobes (Peptostreptococci, Bacteroides species)

Anaerobic organisms, such as species of Bacteroides and Veillonella

Gram-negative organisms, such as Haemophilus parainfluenzae and Bartonella henselae

Question 4

What are the symptoms of RPA?

Answer 4

sore throat, fever, dysphagia, difficulty breathing

Question 5

What are the signs of RPA?

Answer 5

posterior pharyngeal wall oedema (commonly unilateral), stridor, neck stiffness, neck swelling, fever, tachycardia

Question 6

What are the ix done for RPA”

Answer 6

Lateral neck XR -> retropharyngeal / prevertebral thickening

• Adult: widening of the retropharyngeal soft tissues > 7 mm at C2, and > 14 mm at C6
• Children: Generally, the anteroposterior diameter of the prevertebral soft tissue space in children should not exceed that of the contiguous vertebral bodies.

CT neck: retropharyngeal collection seen

Lab investigations: FBC (raised WBC), raised ESR, blood cultures

Question 7

What are the complications of RPA?

Answer 7

• Upper airway obstruction
• Mediastinitis

Aspiration pneumonia

Necrotising fasciitis (most feared)
- An infection in the "danger" space between the alar and prevertebral fasciae may drain by gravity into the posterior mediastinum, resulting in mediastinitis and empyema. 

Spread to adjacent spaces e.g. parapharyngeal space, danger space etc.

Spread of infection to carotid sheath; (internal carotid artery erosion, jugular vein thrombophlebitis) and then mediastinum (acute necrotizing mediastinitis with widened mediastinum on chest x-ray )

Infection can spread and enter the skull base (epidural abscess) or the posterior mediastinum (pericarditis).

Atlantoaxial dislocation

Question 8

How is RPA managed?

Answer 8

Secure airway if necessary- endotracheal intubation or tracheostomy

IV antibiotics

IV fluid for rehydration

Surgical drainage of abscess
= Transoral
= Transcervical