A parapharyngeal abscess develops principally as a complication of deep neck infections caused by various gram-positive and gram-negative bacterial pathogens, and its life-threatening nature mandates early recognition. Symptoms include fever, limited neck movement, voice changes, stridor, proximal lymphadenopathy with swelling of the neck, and breathing difficulties. A thorough clinical examination, microbiological confirmation of the underlying cause, and imaging studies of the neck (mainly computed tomography) are vital components of the diagnostic workup.
Deep neck space infections can be particularly troubling in the absence of an early diagnosis. A parapharyngeal abscess, roughly defined as an infection of the parapharyngeal space, is seen after dissemination of other more common deep neck space infections (for example peritonsillar, tonsillar, or retropharyngeal abscesses, as well as tonsillitis)   , or previous upper respiratory tract infections , but it may be the primary source of infection as well . The clinical presentation is diverse and most frequent symptoms are fever, the stiffness of the neck accompanied by a swelling or a bulging mass, lymphadenopathy, and trismus (spasm of the jaw that results in impaired temporomandibular joint activity)   . Additional findings include torticollis, a range of respiratory complaints (stridor, voice changes, and sleep apnea), drooling, and odynophagia   . Most studies address that children in their first decade of life are the principal population in whom parapharyngeal abscesses are recognized   , but the condition may be seen in patients of all ages. Because of the close proximity to the bronchial tree, complications such as aspiration pneumonia, mediastinitis and rheumatic fever/glomerulonephritis in the setting of streptococcal infection have been reported .
The diagnosis of a deep neck space infection must be suspected in the presence of a bulging mass in the neck accompanied by voice changes, fever, and respiratory difficulties. A thoroughly obtained patient history that will note the course and progression of symptoms, and a detailed physical examination during which inspection and palpation of the neck, pulmonary auscultation, and a complete ear, nose, and throat (ENT) exam are conducted, are the first steps that will allow sufficient evidence to be raised towards a parapharyngeal abscess. Once a presumptive diagnosis is made, a microbiological investigation is recommended as the next step in the workup. Bronchoalveolar aspirates, blood cultures, or needle aspiration have all been described as potential methods to obtain a viable sample for identification of the underlying cause  . Klebsiella pneumoniae, streptococcal, and staphylococcal species are primary pathogens involved in the development of deep neck space infections, but it is not uncommon for a polymicrobial infection to be present  . Imaging studies are equally important in the assessment of a parapharyngeal abscess. Ultrasonography of the neck and chest X-rays (if the involvement of pulmonary system is suspected) are viable first-line methods, but computed tomography (CT) is the gold-standard due to its ability to confirm the exact location of the abscess and determine its spread into adjacent tissues  .