Differentials
Acute epiglottitis
SIGNS / SYMPTOMS
Difficult to distinguish from RPA but generally has a more acute onset.
History of difficulty in breathing.
INVESTIGATIONS
CT scan would not show a ring-enhancing lesion in retropharyngeal space.
Lateral soft tissue neck x-ray shows radio-opaque shadow of inflamed epiglottis.
Laryngotracheobronchitis
SIGNS / SYMPTOMS
Barking cough.
INVESTIGATIONS
CT scan would not show a ring-enhancing lesion in retropharyngeal space and would show clinically normal appearance of oropharynx.
Meningitis
SIGNS / SYMPTOMS
Headache; purpuric rash may also be present in some cases.
INVESTIGATIONS
CT scan would not show a ring-enhancing lesion in retropharyngeal space.
Positive finding on lumbar puncture.
Tonsillitis
SIGNS / SYMPTOMS
Clinical examination confirms presence of infected tonsils with normal appearance of posterior pharyngeal wall.
INVESTIGATIONS
Diagnosis is clinical.
Peritonsillar abscess
SIGNS / SYMPTOMS
Peritonsillar swelling and medialised uvula.
Normal appearance of the posterior pharyngeal wall on clinical examination.
INVESTIGATIONS
Aspiration or incision and drainage of the swelling confirms diagnosis.
Retropharyngeal lymphadenopathy
SIGNS / SYMPTOMS
Non-fluctuant swelling of posterior pharyngeal wall.
INVESTIGATIONS
CT scan with contrast differentiates between lymphadenopathy and abscess.
Nasopharyngeal carcinoma
SIGNS / SYMPTOMS
Persistent lymphadenitis.
Non-resolving symptoms despite adequate treatment.
INVESTIGATIONS
Biopsy and cytology confirms presence of neoplasia.
Epstein-Barr virus infection
SIGNS / SYMPTOMS
Hepatosplenomegaly and generalised lymphadenopathy may be present.
INVESTIGATIONS
Paul-Bunnell or monospot tests are positive.
Retropharyngeal calcific tendonitis
SIGNS / SYMPTOMS
Signs and symptoms may mimic RPA.
It is self-limiting and usually settles after 2 weeks.
INVESTIGATIONS
CT scan shows calcification anterior to the C1 and/or C2 vertebral body(s) with a non-ring-enhancing fluid collection in the prevertebral space.[28]
Branchial cyst
SIGNS / SYMPTOMS
Congenital abnormality arising due to failed obliteration of the second branchial cleft. May mimic signs/symptoms of a retropharyngeal collection in the neonate.[29]
INVESTIGATIONS
A contrast-enhanced CT scan shows a cystic and enhancing mass in the neck. MRI may allow for finer resolution during pre-operative planning.
Kawasaki disease (KD)
SIGNS / SYMPTOMS
May have features of RPA, but lymphadenopathy is rarely seen in isolation or as the initial presentation.
Diagnostic features of KD include more than 5 days of pyrexia with 4 of 5 clinical criteria: non-purulent bulbar conjunctivitis, changes in the lips or oral cavity, polymorphous exanthem, erythema with later desquamation of the extremities, and at least one cervical lymph node >1.5 cm in size.
INVESTIGATIONS
CT scan shows features that are very similar to retropharyngeal abscess, so the clinician must rely on the clinical features.[30]
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