Role of Oral Radiologist in the early detection and management of COVID related Mucormycosis

 Mucormycosis AKA Black Fungus is an opportunistic infection caused by a group of fungi called mucormycetes

It is normally cultured from human oral, nasal, throat swabs and they're harmless and non- pathogenic in a normal individual.

Susceptible individuals: 

• Debilitated people
• People with uncontrolled diabetes mellitus
• People undergoing corticosteroid therapy
• People undergoing immunosuppressive therapy
• AIDS
• Blood malignancies 
• Malnutrition
• Irradiation
• TB

It's rapidly progressing, invasive, disfiguring and is fatal when it involves the brain

Identifying and treating at the earliest is of utmost importance. 

Variants:

Pulmonary

Gastrointestinal

Rhinocerebral

A subtype of rhinocerebral, rhinomaxillary mucormycosis is a commonly seen complication in post COVID individuals. It has resulted in several deaths in India. An awareness about the clinical and radiological features is important to include this in differential diagnosis and save lives.

Fungal infection progresses by invading vessels resulting in thrombosis, ischemia and necrosis

Mortality rate: 50-100 %

Clinical features:

• Nasal discharge
• Ptosis, proptosis
• Fever
• Swelling/puffiness of cheek
• Paresthesia and numbness of face
• Unilateral facial pain/ headache

Oral manifestations:

Early symptoms resembling dental pain and sinusitis

Ulceration of palate, gingiva, lips, vestibule, alveolar ridge

Palatal ulcers resulting in denudation, sloughing, and necrosis

Mobility of teeth that were otherwise normal

Imaging:

MRI (thickening of sinus mucosa and patchy destruction of sinus walls), CT

CBCT (low cost, low exposure and highly efficient) 

CBCT helps in early detection of mucormycosis. Certain features include

• Polypoid thickening of sinus mucosa
• Opacification of the sinus
• Thinning or loss of cortical outlines
• Patchy bone destruction
• Erosion of sinus floor, nasal wall, nasal floor
• Erosion of maxilla
• Destruction of sinus walls
• Thinning of trabeculae
• Interradicular bone destruction (mild to extensive resulting in teeth exfoliation)

All sections should be observed bilaterally 

comparison with contralateral side is important 

Case history is important. In any susceptible patient with history of COVID infection, mucormycosis should be included in the differential diagnosis. 

A very important aspect about mucormycosis is that NEGATIVE CULTURE DOES NOT RULE OUT mucormycosis. fungus is difficult to culture from infected tissue.

Biopsy must be performed when mucormycosis is suspected

Treatment:

Surgical debridement followed by systemic Amphotericin-B 

When left untreated, the infection spreads to the orbit resulting in loss of vision, then into the brain causing death.  

Person to person transmission is highly unlikely.

Any patient who presents with dental symptoms should be thoroughly examined for the presence of oral lesions and imaging should be advised as required. Clinician should bear in mind that certain cases might just have the symptoms of maxillary sinusitis. Dentists, oral physicians and radiologists can detect the infection at its early stages with the help of proper imaging modalities. 

figure shows a case of mucormycosis involving the orbit. (picture courtesy *)

*unknown