Ear, Nose & Throat
A 3 year child is brought to the Emergency Department by her concerned parents. They describe 2 days of fever, neck pain and poor oral intake. A junior colleague initially assessed the child and arranged a cervical x-ray. What is the most likely diagnosis?
Answer:
The x-ray demonstrates soft tissue swelling posterior to the pharynx, with a widening of the prevertebral soft tissue, suggesting a retropharyngeal abscess. In children, presentation may be vague and depends on the stage of disease, but characteristic symptoms include spiking fever, neck pain (especially on movement) or torticollis, and dysphagia. Other common symptoms include irritability, malaise, mild photophobia, and odynophagia (painful swallowing). Odynophagia causes drooling, poor oral intake, and anorexia. Less common symptoms include trismus (lockjaw), dysphonia (hoarseness), stridor, or sleep apnoea. The child may also be seen to pull at their ears or throat, which indicates pain.Retropharyngeal Abscess
Ear, Nose & Throat
Last Updated: 13th February 2023
A retropharyngeal abscess is a neck infection which forms in the potential space between the prevertebral fascia posteriorly, the posterior pharyngeal wall anteriorly, the base of the skull superiorly and the mediastinum inferiorly.
Aetiology
Retropharyngeal abscess is most common in young children between two and six years old. Children are more frequently affected by the condition because they have an increased frequency of upper respiratory tract infections and oropharyngeal trauma, as well as the tendency towards suppuration in the retropharyngeal lymph nodes.
The origin is usually spread of infection from an upper respiratory tract infection e.g. pharyngitis, tonsillitis, sinusitis, otitis media, dental infections. Occasionally retropharyngeal infections can result from a variety of other miscellaneous causes, including trauma/foreign body injection. Immunocompromised patients are also at increased risk of developing a retropharyngeal abscess.
Retropharyngeal abscess often is a polymicrobial infection. The predominant bacterial species are Streptococcus pyogenes, Staphylococcus aureus, and respiratory anaerobes (including Fusobacteria, Prevotella, and Veillonella species).
Clinical features
In children, presentation may be vague and depends on the stage of disease, but characteristic symptoms include spiking fever, neck pain (especially on movement) or torticollis, and dysphagia. Other common symptoms include irritability, malaise, mild photophobia, and odynophagia (painful swallowing). Odynophagia causes drooling, poor oral intake, and anorexia. Less common symptoms include trismus (lockjaw), dysphonia (hoarseness), stridor, or sleep apnoea. The child may also be seen to pull at their ears or throat, which indicates pain.
In adults, the presentation may be more specific with drooling and dysphagia, but is usually more insidious in onset. Up to one third of patients with a deep neck abscess have diabetes mellitus.
Airway compromise usually presents with symptoms of dyspnoea, distress, and fatigue.
An attempt should be made to examine the oral cavity and neck to look for tonsillar swelling, oropharyngeal swelling, and lymphadenopathy. Other important observations may be made such as drooling, dyspnoea, torticollis, and neck swelling/mass. In children the examination may be limited depending on the age and co-operation of the child (and parents).
Diagnosis
A full blood count with differential should be ordered initially to confirm neutrophilia.
Radiological investigations are required to confirm diagnosis. The selected investigation depends on the degree of suspicion and access to the different imaging modalities, as well as the severity of the case. Plain x-ray of the neck will provide some evidence of an RPA but is less sensitive and less specific than a CT scan; lateral soft tissue x-ray of neck will demonstrate soft tissue swelling posterior to the pharynx, with a widening of the prevertebral soft tissue. A CT scan is the definitive investigation and will demonstrate a ring-enhancing lesion in the retropharyngeal tissues when performed with contrast.
Differential diagnosis
- Acute epiglottitis
- Bacterial tracheitis
- Croup
- Tonsillitis
- Peritonsillar abscess
- Retropharyngeal abscess
- Angioedema/anaphylaxis
- Tumours
Management
If there is a strong suspicion of an RPA and the airway is compromised (indicated by stridor, tachypnoea, and decreased oxygen saturation as the patient becomes fatigued), the patient should be admitted to hospital immediately. Initial medical management includes the use of corticosteroids, nebulised adrenaline (epinephrine), and antibiotics. If this is not rapidly effective, the patient should be taken to theatre promptly for examination under anaesthesia (EUA) with a view to surgical drainage.
Even in the absence of airway compromise, the patient should still be admitted to hospital and carefully observed. If the airway is not an immediate concern and there is no evidence of mediastinal extension of the abscess, treatment with empirical intravenous antibiotics for 24 to 48 hours should be initiated promptly. Corticosteroids may also be used in conjunction with the intravenous antibiotics. Prompt treatment with antibiotics, with or without corticosteroids, can cause resolution or prevention of disease progression, in some patients with an early presentation (where there is only cellulitis rather than true abscess formation), thereby avoiding the need for surgical drainage. Failure of initial medical treatment (i.e. no symptomatic improvement, continuing swinging pyrexia, deterioration of vital signs), and/or the presence of a defined abscess on imaging should prompt the need for EUA with a view to peroral surgical drainage.
Complications
- Recurrence of abscess
- Necrotising fasciitis
- Aspiration pneumonia
- Meningitis
- Epiglottitis
- Mediastinitis
- Pericarditis
- Pyopneumothorax/pneumomediastinum
- Empyema/pyothorax
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- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
