Fungal Oto-Mastoiditis- A Rare Presentation in Immunocompetent Individuals

Abstract

Fungal oto-mastoiditis is a rare condition and is often associated with host immunodeficiency. It has to be considered as a differential diagnosis among patients presenting symptoms despite an adequate antibacterial therapy. A 23-year-old female presented to the ENT OPD with complaints of occasional left ear discharge, since 2 years which was associated with itching, pain and reduced hearing. There were no complaints of swelling or pain behind the ear. Otoscopic examination revealed bulging, congested, immobile tympanic membrane in the left ear. Pure tone audiometry revealed 48.33 dB moderate mixed type of hearing loss in the left ear and tympanometry done showed type B curve in the left ear. Patient was taken up for exploratory tympanotomy where middle ear and antrum was filled with granulation tissue and peculiar looking, unusual greenish-brown debris suspicious of fungal otomycotic debris. Ossicular mobility was attained after clearing the disease from the middle ear and cortical mastoidectomy was completed. KOH study of the debris removed was positive for fungal elements as seen. Histopathological examination revealed features suggestive of Chronic suppurative otitis media. Specimen was sent for fungal culture where Aspergillus species was isolated. Patient was started on Voriconazole orally twice a day for 2 weeks. Postoperative period was uneventful and patient’s hearing improved. ^® Fungal oto-mastoiditis is a rare but reported entity, which is usually seen in immunocompromised patients. A high index of suspicion is required to reach an early diagnosis and administer suitable treatment, especially when it presents in immunocompetent individuals.

Introduction

Fungal oto mastoiditis is a rare condition and is often associated with host immunodeficiency. It has to be considered as a differential diagnosis among patients presenting with prolonged otorrhoea, otalgia and rapidly progressing audio vestibular symptoms and signs, despite an adequate antibacterial therapy [1]. It is difficult to diagnose, and if not detected early, can be fatal. Treatment consists of surgical debridement, attempts to control the underlying immunological condition and antifungal chemotherapy. Otomycosis is a fungal infection of the external ear canal that can also affect the middle ear and in complicated cases, the mastoid cavity [2]. In this case report, we describe a rare case of an immunocompetent patient who presented with clinical features suggestive of fungal otitis externa along with hearing loss and a bulging tympanic membrane that turned out to be fungal oto mastoiditis, after exploratory tympanotomy.

Case Report

A 23-year-old female presented to the ENT OPD with complaints of occasional left ear discharge, since 2 years which was intermittent (3 episodes per year for 2 years), scanty in amount, relieved partially by medications in the form of ear drops and tablets and was also associated with itching and pain. Patient also complained of reduced hearing. There were no complaints of swelling or pain behind the ear. There was no history of recurrent upper respiratory tract infections. Otoscopic examination revealed bulging, congested, immobile tympanic membrane in the left ear and normal tympanic membrane in the right ear. Tuning fork tests revealed Rinne’s negative for all three frequencies in the left ear and Weber’s test was lateralized to the left ear. Pure tone audiometry revealed 48.33 dB HL (Moderate mixed) hearing loss in the left ear and normal hearing in the right ear and tympanometry done showed type B curve in the left ear (Fig. 1).

Fig. 1.

PTA suggestive of left ear moderate mixed hearing loss

In view of the hearing loss and patient’s financial constraints that did not allow for a HRCT Temporal bone to be done, patient was taken up for exploratory tympanotomy. On exploration, middle ear was filled with granulation tissue and peculiar looking, unusual greenish-brown debris suspicious of fungal otomycotic debris which was covering the incudo stapedial joint, incudo malleal joint and the hypotympanum (Fig. 2). The debris was cleared. Drilling of the mastoid revealed granulation tissue and similar greenish-brown debris resembling otomycotic foci along the perifacial air cells, anterior epitympanum, fossa incudis and other spaces as well. Ossicular mobility was attained after clearing the disease from the middle ear and the incudo stapedial joint. Cortical mastoidectomy was completed and disease clearance done. The removed debris was sent for histopathological examination and KOH study. KOH was positive for fungal elements (Fig. 3). Histopathological examination revealed mixed inflammatory infiltrate, congested blood vessels and necrotic debris- features suggestive of Chronic suppurative otitis media. Specimen was sent for fungal culture where Aspergillus species was isolated. Patient was started on Tablet Voriconazole 200 mg orally twice a day for 4 weeks. Postoperatively, follow up till 6 months was uneventful and patient’s hearing improved.

Fig. 2.

Intraoperative image of greenish-brown debris resembling otomycotic focus in (a) middle ear cavity and (b) mastoid antrum

Fig. 3.

KOH study positive for fungal elements

Discussion

Fungal mastoiditis presenting in immunocompetent individuals is a rare occurrence and very few cases have been reported.

Among the few reported, is a study done by Reena Varghese et al. which mentioned seven cases of fungal tympano mastoiditis, all occurring in immunocompetent adults [1]. Similarly, our patient was also an immunocompetent female with no prior comorbidities or history of steroid use.

Due to the barrier of the tympanic membrane and the absence of exposure of the eustachian tube to inhaled fungal, invasive fungal infections of the tympano mastoid region is relatively rare. Fungal mastoiditis can lead to grave complications such as facial palsy, sensorineural deafness and local destruction.

Nasopharyngeal, haematogenic, meningogenic and tympanogenic are the postulated varied routes of entry to the temporal bone. A tympanogenic route is thought to exist when infection spreads from the external canal or middle ear into the temporal bone.

In our case, the patient presented with features suggestive of fungal otitis externa with hearing loss and bulging tympanic membrane and fungal oto mastoiditis was discovered intraoperatively. The bulge in the tympanic membrane can be explained due to the accumulation of large quantity of otomycotic debris. In our patient, we suspect the source of infection to be fungal otitis externa. According to a study done by Ahmed Abdul et al., destruction of the mastoid bone structure might be attributed to a mycotoxins produced by the fungus or due to chronic specific inflammation [3]. In our case, bone destruction was not seen but middle ear had significant granulation tissue with edema.

Lymphocytes secrete cytokines responsible for hypersensitivity reaction and tissue destruction [3]. Histopathology of our case showed mixed inflammatory infiltrate encompassing lymphocytes, eosinophils, macrophages and giant cells.

Another condition that should be ruled out is Allergic Fungal Otomastoiditis as mentioned by a study done by Hiroshi et al. who concluded that it should be considered in patients presenting with otomastoiditis with thick and dense mucin in the middle ear [4]. This mucin was absent in our case. Singh et al. proposed working criteria for diagnosing AFOM which included:

1. An immunocompetent individual with or without type 1 hypersensitivity history;

2. The presence of thick mucin with peanut butter-like consistency or polypoidal tissue in the tympanic cavity without other systemic involvement;

3. Heterogeneous signal intensity in the tympanic cavity with bony expansion and resorption on radiology;

4. Fungal elements in the background of allergic mucin without invasion on histopathology; and.

5. Response to local or systemic steroid medication [4].

Management of fungal mastoiditis include control of the immunocompromised condition if any and surgical debridement to remove diseased tissue. In our case, cortical mastoidectomy was done for disease clearance. Swain et al. has advocated Voriconazole as a newer generation azole group of antifungal agent with successful outcomes [5]. Voriconazole acts by blocking the synthesis of ergosterol through the inhibition of CYP-dependent lanosterol 14α-demethylase. The treatment period of antifungal therapy varies with duration ranging from 3 to 77 weeks [5]. For our patient, Tablet Voriconazole 200 mg was given twice a day for 4 weeks and postoperatively showed a successful successful outcome which can be noted in the post-treatment PTA done after 6 months (Fig. 4).

Fig. 4.

Post-treatment PTA done after 6 months which showed and improvement of hearing from preoperative value of 48 dB moderate mixed type of hearing loss

Conclusion

Fungal otomastoiditis is a rare but reported entity, which is usually seen in immuno-compromised patients. A high index of suspicion is required to reach an early diagnosis and administer suitable treatment, especially when it presents in immunocompetent individuals.

Funding

The authors declare that we received no fundings from any external or internal agencies, commercial or non-profit sectors.

Declarations

Consent for Publication

The authors hereby confirm that appropriate consent has been taken from the patient and the attender in their vernacular language for publication.

Competing Interests

Authors declare none.