Cervical necrotising fasciitis: a rare complication of infectious mononucleosis

Abstract

Cervical necrotising fasciitis (NF) is an aggressive polymicrobial infection of the subcutaneous tissues in the head and neck. We present a case of a healthy 19-year-old man who developed cervical and upper mediastinal NF after an initial presentation of infectious mononucleosis (IM). He was treated with broad-spectrum antibiotics in addition to incision and drainage of an anterior neck and upper mediastinal abscess. He progressed favourably after ten days of hospitalisation and was discharged home on intravenous antibiotics. This is a unique case of cervical NF as a sequelae of IM in a previously healthy paediatric patient.

Background

Cervical necrotising fasciitis (NF) is a life-threatening polymicrobial infection of the subcutaneous soft tissues of the head and neck. It is characterised by a rapid progression of infection that spreads along fascial planes leading to tissue necrosis in multiple compartments, systemic toxicity and possible death. Cervical NF is most often caused by dental infections, however other reported causes include trauma, salivary gland infections, peritonsillar abscesses and other deep neck space infections.¹ Early cervical NF can appear as a benign superficial cellulitis, but can quickly progress to signs of systemic toxicity with crepitus and blistering of the skin as a late sign from subcutaneous gas formation. Generally, patients who develop cervical NF will have predisposing factors of systemic disease such as diabetes, alcoholism, tobacco use, malnutrition, renal failure, obesity or immunosuppression. Here, we present the case of a previously healthy 19-year-old man who presented with infectious mononucleosis (IM) and developed cervical and upper mediastinal NF.

Case presentation

A 19-year-old man with no significant medical history presented to our hospital with a one week history of worsening odynophagia, fever and myalgia. He had been diagnosed with Epstein-Barr virus (EBV) mononucleosis at his paediatrician’s office and placed on oral prednisone. His outpatient lab work was significant for a positive mononucleosis spot test, EBV early D antigen (EA-D) IgG antibody of 129 U/mL, EBV viral capsid antigen (VCA) IgG antibody of 76.5 U/mL and EBV VCA IgM antibody >160 U/mL. Due to poor oral intake and continued odynophagia, he was admitted to the paediatric unit for intravenous fluid hydration with a consult to our ear, nose and throat (ENT) service.

Investigations

On evaluation by our ENT service, his vitals were stable and he was afebrile. ENT examination demonstrated 3+ symmetrical tonsils with white exudates, mild uvular oedema and bilateral reactive neck lymphadenopathy. His labs were significant for leucocytosis with a white blood cell count (WBC) of 16x10⁹/L, transaminitis with an alanine aminotransferase (ALT) of 576 unit/L, aspartate aminotransferase (AST) of 104 unit/L, alkaline phosphatase of 341 unit/L, and an elevated erythrocyte sedimentation rate (ESR) of 23 mm/hour, and C-reactive protein (CRP) 5.4 mg/dL. A rapid strep test, throat culture and respiratory viral panel were negative. An anterior-posterior/lateral chest X-ray was unremarkable. On hospital day two, he was started on intravenous ampicillin-sulbactam and given one dose of intravenous steroids due to persistent symptoms. On hospital day three, he complained of persistent sore throat. Flexible fiberoptic laryngoscopy at this point revealed enlarged tonsils, but an otherwise normal pharyngeal and laryngeal exam. On hospital day four, he complained of severe anterior neck pain and therefore a CT neck with intravenous contrast was ordered. The CT scan revealed scattered locules of gas and fluid involving the anterior soft tissues of the neck extending around the laryngeal cartilage and communicating with a retropharyngeal fluid collection in addition to extension of gas and fluid into the upper mediastinum (figure 1).

Figure 1.

(A) Physical examination on hospital day four prior to incision and drainage. (B–D) Sagittal, axial and coronal views on CT neck with intravenous contrast demonstrating scattered pockets of fluid and gas in multiple deep neck tissue planes.

Treatment

Given the gas and fluid pockets, a presumed diagnosis of NF was made and the patient was taken to the operating room for incision and drainage and possible tissue debridement. In addition, antibiotics were changed to intravenous vancomycin, clindamycin and ceftriaxone. Intraoperatively, an oblique incision was made along the anterior border of the left sternocleidomastoid muscle and dissection was carried up and down the great vessels and into the superior mediastinum where pus and grey, murky fluid was drained. Loculations were broken up using finger dissection. No frank abscess was identified in the retropharyngeal space and no tissue debridement was performed as all tissues appeared viable. A Penrose drain was placed, which was removed on post-operative day three.

Outcome and follow-up

Throughout the remainder of this hospital stay, the patient progressed favourably and was discharged home after ten days of hospitalisation to complete a course of intravenous ceftriaxone and oral clindamycin for five weeks as per the recommendations of our infectious disease team. Cultures from his neck were positive for Capnocytophaga species A, Veillonella species and Staphylococcus epidermidis. He had an uncomplicated post-hospitalisation course and is doing well one year afterwards.

Discussion

IM is generally a benign self-limited illness characterised by lymphadenopathy, fever and pharyngotonsillitis. Head and neck complications of IM are rare but have been described.^2–5 Johnsen et al described a five percent rate of otolaryngological complications in patients admitted for IM.⁶ These include airway obstruction, peritonsillar abscess, retropharyngeal abscess, descending mediastinitis and other deep neck space infections. Cervical NF as a sequelae of IM, however, has only been described once in an adult patient.⁷ Caballero et al reported the case of a 47-year-old woman with a history of smoking and alcohol abuse who developed epiglottitis and cervical NF from IM. This is the only other documented case in which IM was reported as a precursor to developing cervical NF. To our knowledge, our case is unique as it is the only presentation of IM precluding cervical NF in a healthy paediatric patient.

NF is more likely to occur in immunocompromised adults with a history of immunodeficiency disorders or chronic systemic conditions such as diabetes, chronic renal failure, intravenous drug abuse and alcoholism. The EBV infection itself can cause immunosuppression by inhibiting cellular and humoral immunity.⁸ The tonsils of patients with IM have been shown to contain more species of anaerobic organisms during the acute mononucleosis illness and this is postulated to be due to the immunosuppressive effect of EBV.⁹ EBV has also been shown to damage the pharyngotonsillar squamous epithelium thus inducing bacterial penetration into the tonsillar tissue, which may be the causative mechanism for the development of deep neck space infections in IM.¹⁰ In addition, steroids are often used in treatment of IM, which can further suppress the immune system. Hander et al found a positive correlation between steroid therapy and the development of peritonsillar abscesses in IM.¹¹ Our patient had been treated with a course of oral prednisone as an outpatient and had been given intravenous steroids during his inpatient stay. We postulate that the combination of an EBV infection in conjunction with steroid administration lead to the development of NF in our patient.

The diagnosis of NF in the head and neck can be difficult to make as several head and neck infections such as tonsillitis, pharyngitis and dental abscesses can mimic NF symptoms. The most common signs of NF are local erythema, pain and swelling, while the classic signs of NF such as crepitus, skin necrosis, and bullae will only present in thirteen to thirty one percent of patients.¹² In addition, these skin changes only become evident once skin ischaemia occurs, which is a sign of the late stage of NF in addition to systemic signs such as tachycardia and fever. When NF is suspected, a prompt CT exam should be obtained as this is the best way to visualise tissue oedema and subcutaneous gas accumulation. While CT findings in the early stages of NF are similar to those of cellulitis, later stages may show dermal thickening, inflammatory fat stranding, and superficial or deep fluid and air in the subfascial planes, although this is only seen in about fifty percent of NF cases.¹³

Treatment of cervical NF involves securing the airway, broad antibiotic therapy and surgical intervention. Early surgical drainage and debridement can salvage skin and help stop the spread of infection. The goals of surgery are to eradicate all necrotic tissue and to drain loculated fluid collections. Our patient underwent incision and drainage of the anterior neck and superior mediastinal abscess, however no tissue debridement was performed as all tissue appeared viable with good vascular supply. We believe this may have been due to identifying disease in its early phases before liquefactive necrosis of the tissue developed. It is possible that despite normal gross appearance, there may have been microthromboses or vasculitis of the healthy-appearing tissue as described by Andreasen et al, however this did not manifest in any further tissue destruction.¹⁴ We also considered the option that this was not true NF given that we did not see any tissue necrosis and that the subcutaneous emphysema was the result of an iatrogenic perforation of the pharyngeal mucosa during flexible fiberoptic laryngoscopy rather than from a gas-forming organism. However, we felt this scenario was less likely given the presence of the murky dish-washerlike fluid that was drained from the anterior neck and the growth of anaerobic bacteria which are findings consistent with NF. Furthermore, surgical drainage rather than debridement has been described as sufficient treatment for cervical NF in the past, most notably in a case series from Japan reporting that percutaneous catheter drainage of cervical NF produces similar outcomes as traditional surgical debridement.¹⁵ This group noticed that cervical NF patients often had only a small amount of total necrotic tissue, thus they treated twenty consecutive patients with percutaneous catheter drainage instead of conventional surgical debridement and found a mortality rate of zero percent. We postulate that a certain subset of cervical NF cases can be treated by incision and drainage alone, however more research needs to be done to understand in which cases this strategy is appropriate.

NF is a polymicrobial infection typically classified into four different subgroups based on bacteriology. Type I NF is characterised by obligate and facultative anaerobes. Frequent bacteria found here include Enterobacter, Fusobacterium, Bacteroides and diphtheroids.¹² As these anaerobic bacteria proliferate in the hypoxic tissue environment, they produce gas that accumulates in the soft tissues and gives the classic appearance on X-ray or CT scans. Type II NF is a monobacterial infection most commonly caused by group A Streptococcus. Type III NF is gas gangrene most often caused by Clostridial infections and type IV NF is fungal in origin, most often from candida or zygomycetes infections.¹² Cultures from our patient’s abscess grew Capnocytophaga species A (an anaerobic gram-negative rod), Veillonella species (an anaerobic gram-negative cocci) and S. epidermidis, which are all species of the oral microbiome and have been implicated in dental infections. Interestingly, cultures from the prior Caballero et al case describing NF from IM in an adult also grew Veillonella and Capnocytophaga species.⁷

Complications from NF include mediastinitis, septic shock, airway obstruction, meningitis, carotid artery erosion, thrombophlebitis of the internal jugular vein, and even death, with the most deaths occurring from mediastinitis. Our patient displayed evidence of infection spreading into the upper mediastinum. Descending mediastinitis in patients with IM has been described in four previous cases.⁴ The proposed mechanism of spread is either through direct spread of a pharyngeal abscess through the prevertebral fascia into the mediastinum, or through septic thromboemboli, also known as Lemierre’s syndrome. In our patient, infection may have easily spread through the danger space from the retropharyngeal space down into the mediastinum, or anteriorly from the thyroid downwards into the upper mediastinum.

In conclusion, cervical NF is a rare condition often resulting in fatal outcomes. Here, we present a case of a previously healthy 19-year-old male who developed IM complicated by cervical and upper mediastinal NF. He progressed favourably after incision and drainage and treatment with intravenous antibiotics. Although IM is generally a benign disease, practitioners should be aware of rare but potentially life-threatening complications.

Learning points.

• Cervical necrotising fasciitis (NF) occurs most often in immunocompromised patients, however the combination of infectious mononucleosis (IM) and steroid use can predispose healthy patients to secondary infections.

• When cervical NF is suspected, a prompt CT scan should be obtained to look for tissue oedema and subcutaneous air.

• Surgery for cervical NF does not necessitate tissue debridement. Select cases may improve with incision and drainage alone in combination with broad-spectrum intravenous antibiotics.

• While IM is generally a benign disease, practitioners should be aware of rare but potentially life-threatening complications including cervical NF.