## 3 Etiopathology  
The most common etiological factors associated with DNI are dental infection, pharynx infection followed by upper respiratory tract infection (URTI), external or internal trauma, congenital sinus, and malignancy. Table 1 shows that in different studies from the last 15 years, the most common etiology in DNI with DNM is pharyngo-tonsillar, in contrast to DNI in which odontogenic etiology predominates. A significant percentage also represents unknown etiology, or etiology grouped under other causes [12; 13; 14; 15; 16; 17; 18; 19]. Thus, there has been a decrease in supplements due to odontogenic causes in the last 5 years; this is possibly also a result of the application of preventive measures in the dental network, and of the timely resolution of infections due to odontogenic causes. In the same context, there has been an increase in DNI of unknown etiology, from 11.8% to 23.8% in the last 5 years (Table 1). The most common spaces involved are the suprahyoid spaces. The most frequent space involved both unilaterally and bilaterally is the submandibular space (66.6%). This is followed by the sublingual and parotid spaces and the anterior visceral space. Figure 3: A PRISMA diagram of the current scoping review. The exact most common location of DNI remains unclear, due to varying eligibility criteria in different studies. Some authors report a high incidence of peritonsillar abscesses, though these are generally not considered deep-space infections. The submandibular space is the most frequently identified site of DNI, followed by the parapharyngeal space. Certain studies suggest that the involvement of multiple spaces in DNI may be a prognostic factor for increased complication rates, though it does not necessarily correlate with extended hospitalization [9; 20; 21]. According to a multivariate analysis by [PERSON] et al., a leukocyte count exceeding 11,109/L is a significant predictor of extended hospitalization, though it does not imply an increased risk of complications [22]. Importantly, most lesions have an otorhinolaryngological (ORL) and oromaxillofacial (OMF) starting point. The infection spreads, through contiguity, through the lymphatic or hematogenous route, following contamination of mucosa mainly of dental, buccal, pharyngeal, laryngeal, submaxillary, or parotid glandular inflammatory origin, but also of iatrogenic origin, following endoscopic maneuvers or orrotracheal intubations. Etiologically, infection is most frequently caused by aerobic and anaerobic germs. Commensal bacteria of the oropharyngeal flora play a role in the etiopathogenesis of cervical suppuration. When a bacterial or viral infection causes a physiological imbalance, these commensal bacteria become aggressive and invasive. Depending on the virulence of the germs, but also on the characteristics of the patient (immunocompromised--cancer, HIV, diabetes mellitus, elderly) and treatment with NSAIDs or corticosteroids, the infection may remain localized for a long time, and then turn into an abscess or progress to a diffuse and extensive infection, which is sometimes necrotic, in the form of necrotic extensive cervical cellulitis or adenoflegmon [23]. Neck abscesses are produced by bacteria found in the pharynx and oral cavity. The most common bacteria involved in DNI in many studies are Streptococcus viridans and Staphylococcus aureus. In cases of DNI with DNM but also necrotizing fascitis, Gram-negative bacteria, but also polymicrobial infections, have been described [17; 23; 24]. In some studies, an increased proportion of patients whose bacterial culture is negative has been found [25; 26], this being due to the empiric administration of antibiotics before hospitalization. Pyogenic streptococcus is the most aggressive form of the bacteria, because it releases streptodromases and streptokinases that determine bacterial tissue progression, as well as tissue necrosis. Anaerobic proliferation is favored by edema and venous thrombosis, which accentuate the effect of tissue anaerobic bacteria.