Spontaneous retropharyngeal hemorrhage

Spontaneous retropharyngeal hemorrhage, also known as spontaneous retropharyngeal hematoma, describes an accumulation of blood in the retropharyngeal space. It is a rare but potentially fatal entity due to potential for acute airway obstruction and/or rapid internal bleeding.

Epidemiology

Spontaneous retropharyngeal hemorrhage can occur in any age group and generally, there is no gender predominance. Certain predisposing factors tend to occur more frequently in different age groups.

Risk factors

Barring a handful of case reports of truly spontaneous retropharyngeal hemorrhage (i.e. where no precipitating factor could be found), the vast majority of cases can be attributed to a variety of causative or predisposing factors, including ⁶:

• alterations in coagulation
  • anticoagulant and antithrombotic treatment
  • blood dyscrasias
• trauma
  • foreign body ingestion
  • penetrating or blunt force injury
  • surgical intervention and angiography
• abnormal vessels
  • bleeding from esophageal varices
  • ruptured carotid artery
• infection
• tumor
  • metastatic disease
  • ruptured parathyroid adenoma ⁷
• other
  • untreated obstructive sleep apnea ² 

Clinical presentation

Common presenting complaints include sore throat mimicking pharyngitis, odynophagia, and dysphagia ^2,4. If the bleeding occurs quickly, progressive airway obstruction can develop. As these symptoms are non-specific, the clinical differential diagnosis is broad.

The classical signs of spontaneous retropharyngeal hemorrhage are included in the Capps triad ⁶.

Pathology

Spontaneous retropharyngeal hemorrhage dissects through the retropharyngeal space, which is composed mainly of loose areolar tissue and whose anterior border, the buccopharyngeal fascia, is bounded only by the air in the nasopharynx, oropharynx, and hypopharynx. As the hematoma fills this space, symptoms may be delayed by two to three hours ⁴. Should the hematoma become large enough, it may compress the airway and the esophagus.

Radiographic features

Plain radiograph

Anterior displacement of the trachea +/- posterior indentation due to the mass effect of the hematoma can be seen on a lateral neck radiograph.

CT

CT is the primary modality used in the diagnosis of retropharyngeal hemorrhage as patients usually present acutely and need urgent assessment and management in the emergency department. 

The retropharyngeal space is expanded by blood, which will be hyperdense in the acute phase. The pharynx superiorly and the esophagus and trachea are displaced anteriorly and compressed. 

MRI

MRI appearance will vary depending on the rapidity of bleeding and age of the hematoma (see aging of blood on MRI). In most instances cases will present fairly acutely with the following signal intensity in the retropharyngeal fluid ⁶:

• T1: hyperintense
• T2: hyperintense
• T2*/SWI: susceptibility-induced signal loss in parts of the collection
• DWI/ADC: variable

It is particularly important to recognize that blood can result in diffusion-weighted imaging signal characteristics that can mimic pus, with high b=1000 signal and low ADC values encountered; this is important as a retropharyngeal abscess is a common differential diagnosis. 

Treatment and prognosis

Most patients can be managed conservatively with observation, supportive treatment and radiological monitoring ⁵.

However, the proximity of the retropharyngeal space to the airway poses a serious threat to patency should a hemorrhage be rapidly expanding.

There is no single consensus regarding airway management ³. The hematoma may distort the anatomy of the airway, creating a challenge in securing it safety ⁴. While prophylactic endotracheal intubation or tracheostomy may be tempting to secure the airway, such measures may exacerbate bleeding, especially in anticoagulated patients ³.   

Surgical treatment should be avoided unless there is an identifiable treatable cause or compromise of the airway occurs (or is seemingly imminent) ⁴. Small or moderately sized hematomas may resolve with conservative management ⁴. While surgery does lead to earlier recovery and extubation, there is an increased risk of infection ⁵. 

Angiography and vessel embolization may also be considered as an alternative and offers a number of advantages over surgical intervention; rapid access, short procedure time, ability to stem multiple sites of bleeding, ability to localize more superior origin of hemorrhage and a more selective therapeutic vessel occlusion not amenable to open surgery ⁸. 

Medical treatment comprises primarily of reversal of anticoagulation by withholding anticoagulants, and replacement of vitamin K and clotting factors ³. The use of steroids and antibiotics has also been reported but there is little evidence for their use ^4,8.