Discussion
COVID-19 has recently been responsible for a drastic surge in the cases of CAM. We described the DNE findings of 102 patients in the target group who underwent KOH mount irrespective of DNE findings. The observed findings indicate the variable presentation of CAM. The aggressiveness of CAM has changed, with normal nasal findings it has the potential to invade orbit, sinuses, and brain. Imaging plays an important role in making an early diagnosis. The reason attributed for this lack of enhancement is the angioinvasive nature of fungal hyphae which infiltrates the vessels supplying the mucosa5,6,7. In our study, it was found that black turbinate sign was present in the majority of the cases in MRI findings specific to sinonasal involvement of disease. With these findings in the imaging, even a negative DNE mandates a tissue diagnosis.
There is scarce literature among diagnostic utility of nasal endoscopy in relation to common clinical, microbiological, and radiological criteria in CAM.
Mohindra S et al8 reported in their study of 27 patients that the clinical suspicion, supplemented with radiological investigations aid in making a correct diagnosis. In our study, we found that even a negative endoscopy does not rule out the diagnosis of CAM. We would like to propose that all target group patients should be subjected to biopsy for KOH mount and imaging. Ferguson BJ et al9 found that the aggressive evaluation of patients with biopsy contributes to early detection of disease, which was in coherence to our study. We found that in many patients the disease pattern was sinus involvement before nasal involvement. Due to certain limitations of DNE, it is not able to diagnose sinus involvement in endoscopy, where imaging is paramount.
Gillespie MB et al10 showed the approach to diagnose the disease at an earlier stage while it is confined to the nasal cavity before the widespread extension to have a positive impact on survival.
Few authors have reported that turbinate sign is a radiological feature in MRI which can aid in earlier detection of the disease7. It is a moderately specific but significant finding in rhino-orbito-cerebral mucormycosis. In our study, it was found that a black turbinate sign in MRI is specific to sinonasal involvement of disease. To summarize, in the setting of COVID-19, an Otorhinolaryngologist must be vigilant at the imaging findings of CAM. One should have a low threshold for biopsy and imaging even in cases with normal endoscopy in target group patients to reduce false-negative results