Mucormycosis and Its Management

Humans are exposed to Mucormycosis fungi on a routine basis but rarely suffer any disease as their virulence is very low. It mainly affects those who are immunocompromised, with Diabetes Mellitus being the most common pre-disposing factor. Other pre-disposing diseases that may contribute to mucormycosis include prior steroid therapy.

However, in the COVID era, this deadly fungus has caused an epidemic due to the immunocompromising ability of COVID-19 along with the injudicious use of steroids for COVID treatment.

The most common mode of spread of these fungi is through inhalation of fungal spores or conidia. Once these spores enter the tissues, they find their way into the blood vessels and get lodged there. This then induces an inflammatory reaction which leads to the formation of a thrombus that enlarges in size and ultimately leads to compromised blood supply of the tissues, causing ischaemic necrosis. The necrosis is responsible for the blackening of the tissues, which is characteristic of Mucormycosis.

Depending upon the site of entry of infection into the orbit and the structure involved, the first symptoms the patients experience are decreased vision and mono-muscular palsy leading to diplopia. Late features include complete blindness, chemosis/proptosis, total ophthalmoplegia, and optic atrophy on ophthalmoscopy. Further spread intra-cranially may lead to headache, altered consciousness, and death.

Mucormycosis is a rapidly progressive, angio-invasive, commonly fatal, opportunistic fungal infection. The most critical decision in the management of rhino-orbital mucormycosis is whether the orbit should be exenterated. The decision for exenteration often depends on the judgment of the treating otolaryngologist and the ophthalmologist.

This prompted Kshitij Shah and team to devise a scoring system which efficiently tracks the orbital involvement by the disease and also lays down the indications of orbital exenteration in rhino-orbito-cerebral mucormycosis, published in the Indian Journal of Otolaryngology and Head and Neck Surgery.

Aims of the Study

• To layout the indications of orbital exenteration in patients with rhino-orbito-cerebral mucormycosis.
• To devise a scoring system that predicts the stage at which the exenteration needs to be carried out.

A scoring system was devised by a team of experienced Otorhinolaryngologists and Ophthalmologists from prior experience in managing mucormycosis. A total of 15 patients were included.

The scoring system was based on 3 main criteria, namely:

• Clinical signs and symptoms.
• Direct and Indirect Ophthalmoscopy.
• Imaging

The scoring system was applied to the patients. Depending on the score, surgical debridement from the nasal/paranasal/oral region ± orbital exenteration was carried out within a period of 24–36 hours of admission. Inj Amphotericin-B intravenously was started after an initial sensitivity test dose at a strength of 1 mg/kg/day and continued till a total dose of 2–3 g was completed.

A repeat nasal endoscopy was performed and tissue from the suspected diseased area was sent for microscopic examination on KOH mount. If KOH mount was found negative, Amphotericin-B was stopped. Patients were then discharged and followed up on an OPD basis.

Based on the vision, salvage ability of the eye, likelihood of further spread, and cosmesis, different numbers of points were given to different findings which are listed below:

How the Score was Given:

• 1 point = Mild symptoms/signs
• 2 points = Moderate symptoms/signs
• 3 points = Severe symptoms/signs

A. Clinical

B. Ophthalmology

C. Imaging

Based on the scoring system, it was observed that those patients who crossed a score of 23 were eligible candidates for orbital exenteration as agreed upon by the Otorhinolaryngologist and Ophthalmologists. It was found that most of these patients were in turn positive for mucormycoses on histopathology and are stable now after completion of Amphotericin therapy.

Table 1: Clinical Symptoms

Table 2: Ophthalmology

Table 3: Imaging

Management

Surgical debridement of all the necrosed tissue along with Inj Amphotericin-B (1 mg/kg/day for a total dose of 2–3 g) is the treatment of choice. However, when the orbit is involved, the decision-making is not as direct. The vision is arguably the most important sensation of a human being. The decision to either preserve the eye or exenterate it as a part of surgical debridement has to be taken jointly by the otolaryngologists and the ophthalmologists.

• Orbital Exenteration with Enucleation
• Endoscopic Orbital Exenteration
• Amphotericin-B
• Orbital Reconstruction

The above comprise preferred management options for mucormycosis treatment. The decision has to be a close balance between preserving the eye or preventing further intra-cranial spread and eventually death.

New Management Options

• Posaconazole: It was given after 6 weeks of unresponsive Amphotericin-B treatment and there was significant clinical improvement as early as 7 days into the treatment with continued improvement for 23 weeks of therapy and no adverse reactions attributable to Posaconazole.
• HBO2 and G-CSF are the other medical management options that have shown some promise. They act by enhancing the leukocyte killing capacity and increase oxygen delivery to the tissues. Their role is however only additive to systemic anti-fungals.

The Sion Hospital Scoring System is an accurate and promising measure to solve the dilemma that is associated with orbital exenteration in orbito-rhino-cerebral mucormycosis. This scoring system devised by a team of experienced Otorhinolaryngologists and Ophthalmologists from prior experience in managing mucormycosis is now extensively being used to decide the line of management for the new encounter with the epidemic of the disease in the COVID era.

Source: Kshitij Shah, Varun Dave, Renuka Bradoo, Chhaya Shinde, M. Prathibha; Indian J Otolaryngol Head Neck Surg

https://doi.org/10.1007/s12070-018-1293-8