Functional Endoscopic Sinus Surgery and Recurrence of Post-COVID Mucormycosis

Invasive fungal infections caused by the members of Mucorales (mucormycosis) are relatively rare but have increased in the last years. Compared to other fungal pathogens, such as Aspergillus fumigatus or Candida albicans, only little is known so far on fungal properties leading to successful infection and host immune response to the various representatives of the Mucorales. Mucormycosis is angio-invasive; therefore, it spreads rapidly involving the surrounding bone and the tissues along with the sinuses. These aggressive and highly destructive infections occur predominantly in immunocompromised hosts, especially in patients with haematological malignancies or those receiving haematopoietic stem cell transplantation. Diabetic patients with ketoacidosis and patients with transfusional/ dyserythropoietic iron overload are unique risk groups.

The year 2021 saw the rise of post-COVID mucormycosis predisposing to various factors such as decreased immunity, high blood sugar levels, aggressive use of corticosteroids, oxygen therapy and more. The fungal infection initiates in the nasal or oral cavity after a person inhales the spores. It spreads cephaly into the maxillary sinuses further spreading to the ethmoid, frontal, and sphenoid sinuses. Moreover, the infection through the lacrimal ducts causes orbital cellulitis further aggravating into orbital apex syndrome. Fungal hyphae produce ‘‘rhizoferrin’’, which binds to serum iron. The rhizoferrin-iron complex is important for fungal growth [7, 8]. Hyperglycaemia also stimulates the fungal growth, and there is a reduction in chemotaxis and phagocytic efficiency that permits these innocuous organisms to proliferate [9]. Hence, patients with diabetic ketoacidosis are more susceptible to mucormycosis as they have elevated levels of serum iron [7, 8]. It presents as a necrotic black skin ulceration on the face or neck or as a sinus infection [9]. Due to the aggressive course of the disease, it spreads to the cavernous sinus and to the brain parenchyma through the involvement of the cribriform plates, orbital vessels, or the orbital apex. It is the most fatal infection known to humans because of its rapid dissemination by the blood vessels [10]. Emergent curettage of the sinuses with the removal of the infected bone and tissues is the only treatment.

Functional endoscopic sinus surgery is a minimally invasive procedure that facilitates sinus curettage with nominal bone removal, facilitating passage for dependent drainage. The aim of endoscopic sinus surgery (ESS) in these patients would be to remove necrotic tissue and restore sinus drainage. Endoscopic sinus surgery opens the middle meatus, unplugs any oedematous infundibular mucosa, and enlarges the stenosed ostium, therefore unobstructing the OS and the maxillary sinus. It allows decompression and passive motion of secretions and allows culture of infected mucosa. It aerates the sinus and provides access to remove infected foci [11]. Benefits of using endoscopic sinus surgery include improved visibility, minimal invasiveness, and less operative morbidity especially in some of these patients that can be acutely ill [12].

Surgery is a very important part of the treatment of these patients, largely because of difficulty of medically clearing the disease in necrotic tissue. The principle of surgical treatment is to debride the area until one encounters normal bleeding tissue. The infected mucor tissue bleeds very little because of the vaso-occlusive effect of the fungus and patients may need repetitive debridement [13]. Surgical option mainly depends upon the extension of the mucormycosis which may vary from debridement with Caldwell-Luc, medial maxillectomy, ethmoidectomies, sphenoidotomies, and even radical maxillectomy with orbital exenteration in very severe cases [12].

Caldwell-Luc procedure is performed to completely remove the infected sinus lining, taking care to avoid injury to the natural ostium. The Caldwell-Luc operation uses an external approach for surgical treatment of the severely diseased maxillary sinus. It is an alternative to middle meatal antrostomy done via endonasal endoscopic surgery and was the primary approach used for accessing the maxillary sinus before the advent of endoscopic sinus surgery. [14]

Out of the seventeen patients, 13 patients were known case of diabetes mellitus with a duration of 15 years ± 3 years (range:5–25 years); these diabetic patients and those with raised blood sugar levels were put on insulin therapy. Diagnosis of mucormycosis was made while the COVID-19 treatment was ongoing or 2–3 weeks post-treatment. The common presenting symptom and signs were infra-orbital tenderness (50%), mobile teeth (60%), Pus discharge (40%), severe headache (80%), nasal discharge (16%) and hypoesthesia (20%), chemosis. Frontal sinus perforation was seen in one patient. Fungal culture was positive for Rhizopus (88%) and mucor (12%) species. These patients had an asymptomatic period of 10 days ± 2 days (Table no.1). Previous CT/MRI scan of these patients showed mucosal thickening involving bilateral maxillary sinus, ethmoid with hypertrophied nasal turbinates and erosion of the bone, while one patient showed mucosal thickening of frontal sinus with erosion of the frontal bone. These patients underwent functional endoscopic sinus surgery, one to two months before reporting to our institute. FESS was planned on the basis of the sinus involvement and the procedure being minimally invasive; however, the extensive bony erosion does not facilitate the criteria for ESS.

As FESS facilitates dependent drainage and mucor thickening cannot be facilitated dependently. The only report found in the literature was a report from Taiwan. This involved 9 patients (since 1985), treated with endoscopic sinus surgery. Six had ESS alone and 3 required additional procedures because of the spread of disease. All patients received amphotericin B, and 8 out of 9 survived [15]. FESS will need adjunctive procedures with it if there is extension of the mucor beyond the medial wall of the maxillary sinus or hard palate extension.

The evaluation of pre-operative and post-operative CT-scans after FESS (Fig. 3) revealed residual infected tissue in the sinuses which was inadequately curetted. This led to rapid and continual spread of the fungal elements in the non-infected sinuses. ESS facilitates gravity dependant drainage of the sinuses. FESS proves inadequate if there is extensive bone necrosis along with the sinus lining. Pre-operative evaluation is critical in mucormycosis for deciding the treatment plan. Mucor invades the bone and surrounding vasculature which makes necrotic bone removal along with sinus lining imperative.

Caldwell-Luc procedure or open surgical procedure facilitates adequate removal of the necrotic bone by providing clear visibility. A greater reduction in inflammatory parameters in the sinus mucosa is obtained with Caldwell-Luc operation than with FESS [16].

The hallmarks of successful treatment are control of underlying disease, systemic antifungal therapy, and aggressive surgical therapy [17].

留言 (0)

沒有登入
gif