INTRODUCTION – AGENTS
The head and neck contain a variety of fascial planes forming potential spaces for the spread of infection. If these spaces are seeded, infection may travel to vital structures such as the carotid artery, jugular vein, or mediastinum. Deep neck spaces include the submandibular, peritonsillar, parapharyngeal, retropharyngeal, and prevertebral spaces.
The majority of deep neck space infections are caused by the organisms that frequently infect or colonize the upper aerodigestive tract. These include Streptococcus and Staphylococcus species, as well as bacteria commonly found in the oral cavity such as Bacteroides species, Klebsiella, Escherichia coli, Enterobacter, Actinomyces, and Eikenella corrodens. Often these infections involve mixed flora.
Both adults and young children can develop deep neck space infections. Teenagers and young adults present with peritonsillar space abscesses more commonly than other age groups. A recent dental infection or procedure may be a predisposing factor for a submental or submandibular space infection (see Chapter 3, Dental and Odontogenic Infections). Intravenous or subcutaneous injection of illicit substances into neck veins or tissue also predisposes to neck infections.
The clinical features of a particular deep neck space infection will reflect the anatomic characteristics of the deep neck space involved (Table 10.1). A submandibular space infection may reveal a concomitant infection of the submandibular duct. Odontogenic infections can progress to submental or sublingual infections, and therefore a through dental examination is always indicated.