Odontogenic necrotizing fasciitis: a systematic review of the literature

Necrotizing fasciitis is an aggressive soft tissue infection that can be polymicrobial or due to a single organism [1, 2, 11, 64]. Multiple organisms as well as mixed infections have been reported to cause necrotizing fasciitis of odontogenic origin. In the present study there were 30 different distinct microbiological results isolated from cultures taken from patients with odontogenic necrotizing fasciitis. The microbes isolated ranged from multiple species of Staphylococcus and Streptococcus to mixed anaerobic species and less common bacteria such as Prevotella and Fusobacterium.

Odontogenic necrotizing fasciitis is often characterized by rapidly progressive bacterial infection along multiple fascial tissue planes, leading to vascular compromise, thrombosis, or rupture, along with necrosis of adipose, integumentary, muscular, and subcutaneous and cutaneous tissues. Preexisting immunosuppressive conditions such as diabetes mellitus may predispose patients to odontogenic necrotizing fasciitis, and may increase the mortality risk [1, 2, 11, 64]. In the present study approximately 20% of patients were reported to have DM, and these patients were 9 times more likely to die from their odontogenic necrotizing fasciitis than non-diabetic patients (p = 0.0001). This highlights the need to identify co-morbidities such as DM and treat them appropriately while the patient is concomitantly being treated for odontogenic necrotizing fasciitis. In contrast to DM, only 1.8% of patients in the present study had HIV. These patients did not have an increased risk of death from odontogenic necrotizing fasciitis vs. HIV negative patients (OR = 1.0, p = 1.0). While most cases of head and neck necrotizing fasciitis are odontogenic in origin, idiopathic or pharyngeal etiologies are possible.

Patients with odontogenic necrotizing fasciitis should be treated aggressively with surgical debridement of necrotic tissue and close monitoring with serial debridement and/or frequent dressing changes as indicated. Broad-spectrum IV antibiotics targeting the most common organisms are also vital. In the present study all patients were treated with surgical debridement and IV antibiotics. The most common antibiotics were metronidazole, clindamycin, penicillin, and ceftriaxone but antimicrobial treatment may need to be adjusted once culture results are available in a given case. Debridement of necrotic tissue until viable tissue that bleeds is reached is typically recommended, although care must be taken in necrotizing fasciitis in close proximity to the great vessels, mediastinum, or lungs. The 9.8% overall mortality rate in this study highlights the importance of aggressive treatment with surgery and IV antibiotics. In this study 12.2% of patients were also treated with hyperbaric oxygen, which may be a useful adjunct in refractory cases and when hyperbaric oxygen is readily available. Critical care team involvement is often necessary, and airway management and management of hypotension, hypovolemia, and malnutrition may be necessary in patients with odontogenic necrotizing fasciitis.

Prompt recognition of odontogenic infections that have progressed to necrotizing fasciitis is key. While typical odontogenic infections such as cellulitis and periapical or cervical abscess may present with common or nonspecific symptoms such as swelling, pain, and trismus patients with dusky, tense, insensate, crepitant, or mottled skin, or evidence of involvement of multiple fascial planes and tissue compartments or evidence of gas formation on CT or MRI imaging may have concomitant necrotizing fasciitis needing more aggressive treatment. Survivors of odontogenic necrotizing fasciitis may also have extensive skin and soft tissue loss that may necessitate weeks to months of dressing changes or secondary reconstructive procedures such as skin grafts. Additionally, chronically poor dentition or carious teeth may need to be addressed by dental or oral surgery consultants to prevent recurrence.

The clinical implications of this study are several. The study demonstrates that patients with DM are at greater risk for morbidity and mortality in the setting of odontogenic necrotizing fasciitis. This highlights the need for recognition of DM as a comorbidity using serum glucose testing and hemoglobin A1C testing to assess known and newly diagnosed diabetics. Additionally, diabetics should have tight glucose control during their treatment for odontogenic necrotizing fasciitis, as this may impact the efficacy of their treatment and may affect the length of treatment. The study also demonstrates that a myriad of microorganisms can be causative agents in odontogenic necrotizing fasciitis, making cultures and sensitivities along with broad spectrum antibiotics transitioning to culture-directed antibiotics vital. The study also reiterates the need for aggressive surgical treatment and debridement to remove diseased, necrotic tissue. Extensive reconstructive procedures may be necessary once the necrotizing fasciitis is resolved, but surgical debridement to prevent mortality is of paramount importance. Additionally, the study suggests that adjunctive measures such as hyperbaric oxygen may be beneficial in cases where the patient is stable enough to undergo these procedures, and they are readily available to the treatment team.

The retrospective data in the study makes recall and selection bias a possibility. Nevertheless, the relatively large cohort (164 patients) for this relatively rare disease, combined with the highly significant mortality increase for patients with DM and the consistent therapy applied across the cohort (all patients were treated with surgical debridement and IV antibiotics) supports the validity of the study and its conclusions. The rarity of odontogenic necrotizing fasciitis makes prospective randomized trials difficult to assemble and the often rapid mortality and morbidity might make such trials ethically unfeasible, so relatively large patient cohort, rigorous statistical analysis, and diverse patient base represented in the literature makes this retrospective study a useful addition to the body of scientific knowledge on odontogenic necrotizing fasciitis.

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