Retropharyngeal Abscess

Epidemiology and Etiology

Epidemiology

• Most common in children < 5 years of age
• Less common in adults (due to regression of the retropharyngeal lymph nodes)
• More common in males than females

Etiology

• Abscesses occur due to infections that drain to lateral retropharyngeal lymph nodes.
• May be secondary to: 
  • Upper respiratory tract infections (more common in children) 
  • Otitis media
  • Sinusitis Sinusitis Sinusitis refers to inflammation of the mucosal lining of the paranasal sinuses. The condition usually occurs concurrently with inflammation of the nasal mucosa (rhinitis), a condition known as rhinosinusitis. Acute sinusitis is due to an upper respiratory infection caused by a viral, bacterial, or fungal agent. Sinusitis
  • Pharyngeal trauma (more common in adults) 
    • Foreign body (e.g., fishbone)
    • Endoscopy
    • Dental procedures
• Infections are often polymicrobial and may include: 
  • Aerobes
    • Staphylococcus Staphylococcus Staphylococcus is a medically important genera of Gram-positive, aerobic cocci. These bacteria form clusters resembling grapes on culture plates. Staphylococci are ubiquitous for humans, and many strains compose the normal skin flora. Staphylococcus aureus 
    • Streptococcus Streptococcus Streptococcus is one of the two medically important genera of gram-positive cocci, the other being Staphylococcus. Streptococci are identified as different species on blood agar on the basis of their hemolytic pattern and sensitivity to optochin and bacitracin. There are many pathogenic species of streptococci, including S. pyogenes, S. agalactiae, S. pneumoniae, and the viridans streptococci. Streptococcus pyogenes
  • Anaerobes 
    • Bacteroides Bacteroides Bacteroides is a genus of opportunistic, anaerobic, gram-negative bacilli. Bacteroides fragilis is the most common species involved in human disease and is part of the normal flora of the large intestine. Bacteroides 
    • Fusobacteria

Clinical Presentation

Early symptoms

• May mimic pharyngitis Pharyngitis Pharyngitis is an inflammation of the back of the throat (pharynx). Pharyngitis is usually caused by an upper respiratory tract infection, which is viral in most cases. It typically results in a sore throat and fever. Other symptoms may include a runny nose, cough, headache, and hoarseness. Pharyngitis
  • Fever
  • Sore throat
  • Pharyngeal erythema
• Dysphagia
• Odynophagia
• Neck stiffness/asymmetry 
• Trismus (lockjaw)

Later symptoms

• Ill-appearing, drooling
• “Sniffing” position: leaning forward with neck extended
• Respiratory distress: 
  • Tachypnea 
  • Stridor
  • Nasal flaring
  • Subcostal retractions

Diagnosis and Management

Diagnosis

• Initial work-up includes:
  • CBC
  • Blood culture
• Diagnosis is confirmed by imaging.
  • Lateral neck X-ray:
    • Widened retropharyngeal space 
    • Gas in the retropharyngeal space
  • Computed tomography (CT) of the neck with contrast (gold standard):
    • Rim-enhancing hypodense collection in retropharyngeal space
    • Thickening of the prevertebral space 
    • Presence of air or air-fluid levels

Management

• The 1st and most important step is protecting the airway → intubation if needed! 
• Surgical drainage
• Antibiotics
  • Ampicillin/sulbactam or clindamycin
  • If no response, vancomycin or linezolid

Complications

Retropharyngeal abscesses are considered the most deadly deep neck infection. 

The most common complications include:

• Mediastinitis
  • Occurs due to extension into the posterior mediastinum Mediastinum The mediastinum is the thoracic area between the 2 pleural cavities. The mediastinum contains vital structures of the circulatory, respiratory, digestive, and nervous systems including the heart and esophagus, and major thoracic vessels. Mediastinum and Great Vessels through the “danger space” → space that allows direct spread to the thorax
  • Can progress to acute necrotizing mediastinitis Mediastinitis Mediastinitis refers to an infection or inflammation involving the mediastinum (a region in the thoracic cavity containing the heart, thymus gland, portions of the esophagus, and trachea). Acute mediastinitis can be caused by bacterial infection due to direct contamination, hematogenous or lymphatic spread, or extension of infection from nearby structures. Mediastinitis
  • Mortality rate of 50%
• Internal jugular vein thrombosis 
• Carotid artery rupture → due to extension of the carotid sheath
• Airway obstruction Airway obstruction Airway obstruction is a partial or complete blockage of the airways that impedes airflow. An airway obstruction can be classified as upper, central, or lower depending on location. Lower airway obstruction (LAO) is usually a manifestation of chronic disease, such as asthma or chronic obstructive pulmonary disease (COPD). Airway Obstruction
• Septicemia
• Epidural abscess or diskitis

Differential Diagnosis

• Epiglottitis Epiglottitis Epiglottitis (or "supraglottitis") is an inflammation of the epiglottis and adjacent supraglottic structures. The majority of cases are caused by bacterial infection. Symptoms are rapid in onset and severe. Epiglottitis: an inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body's defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation of the epiglottis most commonly caused by infection with Haemophilus Haemophilus Haemophilus is a genus of Gram-negative coccobacilli, all of whose strains require at least 1 of 2 factors for growth (factor V [NAD] and factor X [heme]); therefore, it is most often isolated on chocolate agar, which can supply both factors. The pathogenic species are H. influenzae and H. ducreyi. Haemophilus influenzae. Epiglottitis Epiglottitis Epiglottitis (or "supraglottitis") is an inflammation of the epiglottis and adjacent supraglottic structures. The majority of cases are caused by bacterial infection. Symptoms are rapid in onset and severe. Epiglottitis presents with “cherry-red” epiglottis, fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever, dysphagia Dysphagia Dysphagia is the subjective sensation of difficulty swallowing. Symptoms can range from a complete inability to swallow, to the sensation of solids or liquids becoming "stuck." Dysphagia is classified as either oropharyngeal or esophageal, with esophageal dysphagia having 2 sub-types: functional and mechanical. Dysphagia, drooling, and difficulty breathing. The condition is commonly seen in unvaccinated children. Treatment is with rocephin and steroids.
• Peritonsillar abscess Peritonsillar abscess A peritonsillar abscess (PTA), also called quinsy, is a collection of pus between the capsule of the palatine tonsil and the pharyngeal muscles. A PTA is usually a complication of acute tonsillitis, an infection caused by group A Streptococci. Patients often present with a sore throat, trismus, and a muffled voice. Peritonsillar Abscess: a bacterial infection (most commonly S. pyogenes) that causes an abscess next to the palatine tonsils. The condition is more common in children and young adults and presents with trismus, fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever, and sore throat, with a “hot potato” voice. Physical exam shows an abscess near the pharyngeal tonsil causing uvula deviation. Treatment is with antibiotics and surgical drainage. 
• Parapharyngeal abscess Parapharyngeal abscess Parapharyngeal abscess is a deep neck infection involving the parapharyngeal space. The infection often arises from the nasal sinuses, mouth, or throat. Patients often present with spiking fever, dysphagia, odynophagia, trismus, and neck pain. Parapharyngeal Abscess or prevertebral space infection: very similar clinical presentation to retropharyngeal abscesses but most often caused by dental infections that extend into the lateral or posterior pharyngeal space. The best way to differentiate pharyngeal from retropharyngeal abscess is by CT of the neck. Treatment is with antibiotics and surgical drainage. 
• Meningitis Meningitis Meningitis is inflammation of the meninges, the protective membranes of the brain, and spinal cord. The causes of meningitis are varied, with the most common being bacterial or viral infection. The classic presentation of meningitis is a triad of fever, altered mental status, and nuchal rigidity. Meningitis: an infection of the meninges Meninges The brain and the spinal cord are enveloped by 3 overlapping layers of connective tissue called the meninges. The layers are, from the most external layer to the most internal layer, the dura mater, arachnoid mater, and pia mater. Between these layers are 3 potential spaces called the epidural, subdural, and subarachnoid spaces. Meninges, the protective membranes around the brain, most often caused by Streptococcus Streptococcus Streptococcus is one of the two medically important genera of gram-positive cocci, the other being Staphylococcus. Streptococci are identified as different species on blood agar on the basis of their hemolytic pattern and sensitivity to optochin and bacitracin. There are many pathogenic species of streptococci, including S. pyogenes, S. agalactiae, S. pneumoniae, and the viridans streptococci. Streptococcus pneumoniae or H. influenzae. Meningitis Meningitis Meningitis is inflammation of the meninges, the protective membranes of the brain, and spinal cord. The causes of meningitis are varied, with the most common being bacterial or viral infection. The classic presentation of meningitis is a triad of fever, altered mental status, and nuchal rigidity. Meningitis presents with fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever, stiff neck, and headache. The condition is differentiated from retropharyngeal abscess by the presence of light sensitivity, headache, and nuchal rigidity. Diagnosis is by lumbar puncture for cerebrospinal (CSF) evaluation. Treatment consists of the rapid administration of antibiotics.