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ORIGINAL ARTICLE Table of Contents  
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Rapid diagnosis and epidemiology of fungal rhinosinusitis in PostCOVID-19 patients

 Department of Pathology, GMC and Sir T Hospital, Bhavnagar, Gujarat, India

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Date of Submission18-Jun-2021
Date of Decision28-Aug-2021
Date of Acceptance29-Sep-2021
Date of Web Publication19-Jan-2023


Background: Fungal rhinosinusitis (FRS) cases are not exiguous for the world. However, their spike as a postCOVID sequelae has alarmed the world, especially India. Adding to the woes is the high mortality rate and poor prognosis associated with acute invasive fungal rhinosinusitis (AIFR) in such immunocompromised patients. In such a scenario, early and precise diagnosis of AIFR is what a patient and physician banks upon. KOH and histopathology are the two frontline investigations for the diagnosis of FRS. Our study aimed at analyzing the cases of FRS by histopathology and comparing these with KOH. Study Design and Materials and Methods: Prospective longitudinal study including suspected postCOVID FRS patients over a period of 1.5 months. Their clinical, histopathological, and KOH findings were then correlated. Results: About 72.5% clinically suspected fungal infection specimens were found to be positive for fungal elements on histopathology. Of these, only 30 cases were positive by KOH mount. Maximum patients belonged to 40-70 years of age; males (67%) more than females. Sites involved were paranasal sinuses (100%), nasal (88%), and orbital (25%). Histopathology revealed mucormycosis (100%) and aspergillosis (16%). Angioinvasion was identified in 38% of the mucormycosis cases. Conclusion: In a state of crisis, when the gold standard for fungal identification i.e., culture can take as many as 21 days for final report and early and judicious antifungal treatment is sine qua non of recovery, histopathology has proved to be better than KOH as far as early and precise diagnosis of fungal elements and their invasion is concerned.

Keywords: Aspergillosis, fungal sinusitis, invasive fungal rhinosinusitis, invasive mucormycosis, KOH, postCOVID

How to cite this URL:
Bapodra MK, Navadiya AJ, Baxi SN, Gohil MR, Parmar PK. Rapid diagnosis and epidemiology of fungal rhinosinusitis in PostCOVID-19 patients. J Microsc Ultrastruct [Epub ahead of print] [cited 2023 Feb 8]. Available from: https://www.jmau.org/preprintarticle.asp?id=368035

  Introduction Top

COVID-19 caused by SARS-CoV-2 has been associated with a wide range of opportunistic bacterial and fungal infections.[1] Both aspergillosis and candida have been reported as the main fungal pathogens for coinfection in people with COVID-19.[2] Recently, several cases of mucormycosis in people with COVID-19 have been increasingly reported worldwide, in particular from India. The primary reason that appears to be facilitating Mucorales spores to germinate in people with COVID-19 is an ideal environment of low oxygen (hypoxia), high glucose (diabetes, new-onset hyperglycemia, and steroid-induced hyperglycemia), acidic medium (metabolic acidosis, diabetic ketoacidosis), high iron levels (increased ferritins), and decreased phagocytic activity of white blood cells due to immunosuppression (SARS-CoV-2-mediated, steroid-mediated, or background comorbidities) coupled with several other shared risk factors including prolonged hospitalization with or without mechanical ventilators.

Of all, the subcategories of fungal rhinosinusitis (FRS), acute invasive fungal rhinosinusitis (AIFS) is one entity that has an aggressive course and often fatal outcome. As its name suggests, invasive FRS can result in dramatic tissue invasion through mucosa, bone, neurovascular structures, and surrounding organs.[3] This, in turn, causes thrombosis with local and/or distant ischemia leading to necrosis. This facilitates spread outside the infected sinus cavity into surrounding tissues and (commonly) the bone. A definition of AIFR has been proposed as “the presence of fungal hyphae within the sinonasal mucosa, submucosa, vasculature, or bone, in the setting of 1 month or less of sinusitis symptoms.“[4],[5] The presence of invasion can only be diagnosed on a histopathological section. No other modality can detect the presence or absence as well as type of invasion. Early diagnosis and initiation of treatment is paramount to improving survival in AIFR.[5]

With this study, we aimed to analyze the cases of FRS by histopathology and correlated the findings with KOH mount results to conclude which of these methods is better for an early and precise that can guide the treating physician in management and prognosis of the patient.

  Materials and Methods Top

Study design

This study design was a prospective longitudinal study.

Study area

Pathology Department, Government Medical College and Sir Takhtasinhji General Hospital, Bhavnagar.

Study material

Specimens were received in the Histopathology department from ENT department of Government Medical College, and Sir Takhtasinhji General Hospital, Bhavnagar.

Study period

This study period was from April 22, 2021 - June 04, 2021 (1.5 months).

Inclusion criteria

All the specimens received from the ENT department during the study period were suspected of postCOVID fungal infection.

Exclusion criteria

Specimens of the postCOVID patients clinically suspected for fungal infection but whose samples were not sent for KOH study in our hospital.


The specimens were received from ENT department in formalin container and were processed as routine histopathological specimens, stained with hematoxylin and eosin (H and E) stain, and then examined under microscope.

Examination and identification of fungus isolates by morphology on H and E-stained section was done as follows:

  1. Presence or absence of fungal elements
  2. Broad, aseptate, right-angled branched hyphae – Mucormycosis
  3. Thin, slender, septate, acute-angled branched hyphae – Aspergillosis
  4. Invasion by fungal hyphae, inflammatory reaction, and other histopathological findings.

In addition, the specimens were analyzed on the basis of age, sex, site, and symptoms as obtained from the ENT department.

The results of KOH mount of the respected patients were obtained from the Microbiology department and were correlated with histopathology findings.

The study was approved by the Institutional Ethics Committee-Ethics committee Government Medical College, Bhavnagar with approval no- 961/2021, approval date - 28/05/2021.

  Results Top

Of the total 138 clinically suspected fungal infection specimens of the postCOVID patients, 100 (72.5%) were found to be have fungal elements on histopathology [Table 1]. These have been termed as “positive cases” hereafter. On correlating these with the KOH results obtained from the microbiology department of our institution, only 30 cases were found to have a positive KOH report [Table 1]. The age group of 40-70 years was most affected by fungal infection [Table 2]. About 67% of the positive cases were males [Table 3]. The paranasal sinuses were clinically affected in all the cases and 88% of patients also presented with nasal symptoms. About 25% of cases also had symptoms related to eyes such as watering of eyes, swelling, or pain in the orbital region [Table 3]. No difference was found in the histopathological positivity of the specimens when compared to the presence or absence of nasal crusting in the patients [Table 3]. As far as laterality is concerned, 87% of patients had unilateral symptoms, of which 54% had left-sided complaints only [Table 3]. All the cases had fungal elements suggestive of mucormycosis alone [Figure 1] whereas 16% of the total positive cases showed coinfection with aspergillosis [Figure 2], [Figure 3], [Figure 4] and [Table 3]. Tissue invasion was seen in all the cases of mucormycosis. However, Aspergillus fungal hyphae did not show any invasion. Angioinvasion was found in 38% of the mucormycosis cases [Figure 5] and [Figure 6] with thrombosis in 5% cases [Figure 7]. In addition, muscular (3%) [Figure 8], bony (9%) [Figure 9], adipose tissue (2%) [Figure 10], intraneural (1%) [Figure 11] and perineural invasions (1%) [Figure 12] were also noted [Table 3].
Table 1: Co-relation of histopathology and KOH results

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Table 2: Age-wise distribution of the total positive (n=100) cases

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Table 3: Composite table for clinical and histological findings in the total positive (n=100) cases

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Figure 1: (a and b) Mucormycosis: Broad, aseptate, right angle (arrow) branched hyphae (H and E, ×400)

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Figure 2: Aspergillosis: Thin, regularly septate hyphae (arrow) (H and E, ×400)

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Figure 3: Coexisting mucormycosis (black arrow) and aspergillosis (green arrow). Note the angle of branching in both (H and E, ×400)

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Figure 4: Coexisting mucormycosis (black arrow) and aspergillosis (Green arrow) along with conidia of Aspergillus (circle) (H and E, ×400)

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Figure 5: Angioinvasive mucormycosis (H and E, ×400)

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Figure 6: Angioinvasive mucormycosis (H and E, ×400)

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Figure 7: Mucormycosis: A thrombosed blood vessel showing fungal hyphae (black arrows). (a) (H and E, ×100) and (b) (H and E, ×400)

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Figure 8: Mucormycosis: Fungal hyphae invading the muscles (marked by M) (H and E, ×400)

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Figure 9: (a and b) Mucormycosis: Bone invasion by fungal hyphae (H and E, ×400)

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Figure 10: Mucormycosis: Adipose tissue invasion by fungal hyphae (H and E, ×400)

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Figure 11: Mucormycosis: Intraneural invasion by fungal hyphae (circle). (a) (H and E, ×100) and (b) (H and E, ×400)

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Figure 12: Mucormycosis: Large areas of necrosis infiltrated by broad, aseptate fungal hyphae along with angioinvasion (V), and perineural invasion (nerve marked by “N” and fungal hyphae marked by arrows). (a) (H and E, ×100) and (b) (H and E, ×400)

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  Discussion Top

FRS and AIFR are not new entities. However, previously considered rare, they have shown steep peaks in the COVID era. Many earlier studies have shown the high mortality rates associated with postCOVID FRS. That is why there is a dire need to diagnose it earliest possible for the treatment to commence soon. To achieve this, we facilitated the biopsy sample transport and sample processing in such a way as to reduce the turnover time of clinically suspected FRS biopsy reports to only 24 h.

The mean age in our study was 54.27 ± 11.43 which is similar to the study done by El Kholy et al.[6] i.e., 52.92 ± 11.30. Histopathological examination revealed mucormycosis in 84% of cases in our study and 77.8% in the study done by El Kholy et al.[6] Coinfection with both mucor species and Aspergillus species was 16% in our study while 8.3% in El Kholy et al.[6] Both of the studies showed 100% sinonasal involvement. Whereas, orbital involvement was seen in 80.6% of cases in the study by El Kholy et al.[6] and only 25% in our study.

As far as sensitivity of KOH is concerned, the present study had only 30% cases which could be detected by KOH mount. Of the rest 70 cases, 60% were found to be positive for fungal infection by histopathology. A similar study by Singh et al.,[7] only 8 of the 14 histopathology positive cases for FRS were found to be positive for KOH mount i.e., around 43% cases showed negative KOH. The various possible reasons for low KOH positivity results in our study could be either sparse fungal hyphae, hyphae entrapped in the mucus, inter-observer variability, or sample not obtained from the proper site i.e., was only obtained from surrounding inflamed area.

AIFR is described by a time course of <4 weeks with predominant vascular invasion occurring in patients with immunocompromised status. The histopathology demonstrates hyphal invasion of blood vessels, which may include the carotid arteries and cavernous sinuses, vasculitis with thrombosis, hemorrhage, tissue infarction, and acute neutrophilic infiltrates.[8] Acute onset of facial pain, fever, and nasal congestion with frequent extension into adjacent structures, including the paranasal soft tissues, orbit, and cranial vault are the common presentations. Orbital involvement can result in loss of vision, while sinus or intracranial extension can be associated with proptosis or neurological impairments, respectively.[9],[10] Detection of invasion demands the need for biopsy and histopathological examination. Besides this, no other modality can comment on presence and type of structures invaded by fungal hyphae. Our study showed 38% angioinvasive mucormycosis with thrombosis in 5% cases whereas 83% in the study by Sravani et al.[11] This was probably because our study population consisted of postCOVID patients which were admitted and biopsied for even slightest doubt of FRS. It has been observed that early diagnosis with limited disease extension has shown good outcomes with minimal mortality and morbidity.

Limitations of this study include relatively limited patient number and single tertiary referral center experience. Furthermore, due to shortage of resources, we were not able to do special stains for fungus in cases which were negative for fungal elements on histopathology but positive by KOH mount.

  Conclusion Top

In a state of crisis, when the gold standard for fungal identification i.e., culture can take as many as 21 days for final report and early and judicious antifungal treatment is sine qua non of recovery, histopathology has proved to be better than KOH as far as early and precise diagnosis of fungal elements and their invasion is concerned.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Kubin CJ, McConville TH, Dietz D, Zucker J, May M, Nelson B, et al. Characterization of bacterial and fungal infections in hospitalized patients with coronavirus disease 2019 and factors associated with health care-associated infections. Open Forum Infect Dis 2021;8:ofab201.  Back to cited text no. 1
Song G, Liang G, Liu W. Fungal co-infections associated with global COVID-19 pandemic: A clinical and diagnostic perspective from China. Mycopathologia 2020;185:599-606.  Back to cited text no. 2
Watkinson JC, Clarke RW. Basic sciences, endocrine surgery, rhinology. In: Scott-Brown's Otorhinolaryngology and Head and Neck Surgery. Vol. 1. Boca Raton, FL, USA: CRC Press; 2018.  Back to cited text no. 3
Craig JR. Updates in management of acute invasive fungal rhinosinusitis. Curr Opin Otolaryngol Head Neck Surg 2019;27:29-36.  Back to cited text no. 4
deShazo RD, O'Brien M, Chapin K, Soto-Aguilar M, Gardner L, Swain R. A new classification and diagnostic criteria for invasive fungal sinusitis. Arch Otolaryngol Head Neck Surg 1997;123:1181-8.  Back to cited text no. 5
El-Kholy NA, Abd El-Fattah AM, Khafagy YW. Invasive fungal sinusitis in post COVID-19 patients: A new clinical entity. Laryngoscope 2021;131:2652-8.  Back to cited text no. 6
Singh AK, Gupta P, Verma N, Khare V, Ahamad A, Verma V, et al. Fungal rhinosinusitis: Microbiological and histopathological perspective. J Clin Diagn Res 2017;11:DC10-2.  Back to cited text no. 7
Chakrabarti A, Denning DW, Ferguson BJ, Ponikau J, Buzina W, Kita H, et al. Fungal rhinosinusitis: A categorization and definitional schema addressing current controversies. Laryngoscope 2009;119:1809-18.  Back to cited text no. 8
Aribandi M, McCoy VA, Bazan C 3rd. Imaging features of invasive and noninvasive fungal sinusitis: A review. Radiographics 2007;27:1283-96.  Back to cited text no. 9
Momeni AK, Roberts CC, Chew FS. Imaging of chronic and exotic sinonasal disease: Review. AJR Am J Roentgenol 2007;189:S35-45.  Back to cited text no. 10
Sravani T, Uppin SG, Uppin MS, Sundaram C. Rhinocerebral mucormycosis: Pathology revisited with emphasis on perineural spread. Neurol India 2014;62:383-6.  Back to cited text no. 11
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Correspondence Address:
Anamika J Navadiya,
Plot No. 65/A-2, Satyanarayan Road, Near Parimalchowk, Bhavnagar - 364 001, Gujarat
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jmau.jmau_63_21


  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11], [Figure 12]

  [Table 1], [Table 2], [Table 3]


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