Cervical necrotising fasciitis complicated by acute mediastinitis

Clinical History

A 59-year-old man consulted the emergency service of our hospital with fever, facial pain, trismus, swelling of the left parotid and submandibular region, dyspnoea and hardening of soft tissues in the floor of the mouth. Potential crepitation was noted in the soft tissues of the left side of the face.

Imaging Findings

CT scan demonstrated severe inflammatory phlegmon with multiple abscesses centred on the left masticator space, affecting sublingual and submandibular spaces, base of tongue and floor of the mouth (Fig. 2), the parapharyngeal space, carotid and retropharyngeal spaces (Fig. 3). Intramuscular abscesses were noted. The largest collections were located in the floor of the mouth and retropharyngeal space. Changes extended caudally into the superior mediastinum with inflammatory fat change and mild pneumomediastinum, secondary to mediastinitis (Fig. 4).
Necrotising fasciitis with severe emphysema affects subcutaneous, intermuscular and intramuscular planes of the left side of the face (Fig. 1), extending into the cervical region.
Hypodense areas with air are noted secondary to muscle belly necrosis (Fig. 5 clearly shows the difference in enhancement between the two muscular bellies of sternomastoid with hypodensity of the left side compared to the right).

Discussion

Cervical necrotising fasciitis (CNF) is a potentially fatal infection characterised by generalised necrosis of the cervical tissues that progresses rapidly. This entity is caused by toxin-producing bacteria such as Group A beta-haemolytic Streptococcus pyogenes and Staphylococcus. Early signs and symptoms include fever, severe pain and swelling, and redness at the wound site. Moreover, fulminant evolution and a high mortality rate are typical of this pathology [2]. In this case we present cervical necrotising fasciitis complicated by acute mediastinitis [1, 2]. When associated with descending necrotising mediastinitis the mortality rate increases to 40% [6]. The thorax has the potential to become rapidly involved if the maxillofacial infection progresses into the retropharyngeal and “danger space”, as in this case [1, 4, 5].
The perineum, extremities and abdominal region are most typically affected by this type of infection [3]. In contrast, NF is less common in the head and neck due to its high vascularity [1, 2, 5, 6].
Diabetes mellitus, chronic alcoholism, intravenous drug abuse, immunocompromised status, and obesity may represent predisposing factors for this pathology [3, 4, 6].
While most of these cases originate from an odontogenic infection (in the context of Ludwig's angina) [1], in this case the origin of infection was a wound located in the floor of the mouth [4]. An early diagnosis, prompt surgical drainage and appropriate medical treatment are key to patient survival, along with aggressive surgical intervention.
Constant collaboration between different specialists is essential for ensuring optimal management of such cases. Critical care physicians, thoracic surgeons and maxillofacial surgeons must work together to make the correct diagnosis and treat the patient to best effect [6].

Differential Diagnosis List

Final Diagnosis

Cervical necrotising fasciitis complicated by an acute mediastinitis.

URL:	https://www.eurorad.org/case/14903
DOI:	10.1594/EURORAD/CASE.14903
ISSN:	1563-4086