Actinomycosis of Middle Ear and Mastoid Presenting as Acute Otitis Media with Mastoiditis- A Case Report

Abstract

Actinomycosis is an uncommon infection of the middle ear.Actinomycosis of ear can mimic other common diagnosis of middle ear. The treatment of actinomycosis of the middle ear differs from that of otitis media caused by aerobic bacteria, therefore an accurate diagnosis is necessary. We present a case of actinomycosis of middle ear in a 36-year-old female. Cortical mastoidectomy with tympanoplasty was performed and the patient is well on follow up. Because of its rarity, case has been reported. Middle ear actinomycosis is a rare and treatable condition. Early diagnosis and appropriate management are crucial to prevent complications and ensure a favourable outcome.

Introduction

Actinomycosis is an uncommon infection of the middle ear. It is a chronic, granulomatous and suppurative infection that rarely involves the middle ear. Actinomycosis of middle ear can mimic other common diagnosis of middle ear [1]. The treatment of actinomycosis of the middle ear differs from that of otitis media caused by aerobic bacteria, therefore an accurate diagnosis is necessary [2].

Case Report

A 36 year old female came with complaint of left ear discharge, reduced hearing since 2 months and severe intolerable earache since 1 month which had no response to conservative treatment. There was no history of headache, vertigo or tinnitus. She had no known comorbidities. On clinical examination, there was pus within the external auditory canal, tympanic membrane was intact bulging and pinkish in posterosuperior and posteroinferior quadrant (Fig. 1).

Fig. 1.

Preoperative appearance of the left tympanic membrane with bulging posterosuperior and posteroinferior quadrant

Preauricular area and post auricular area was normal. Facial nerve was clinically normal. Rest of the physical examination was within normal limits. Haematological evaluation revealed anaemia with haemoglobin 8 g/dL. Blood transfusion was given. C-reactive protein was 13.7 mg/dL. Leucocyte count and random blood sugar was normal. Pure-tone audiometry showed left mixed deafness with air bone gap of 30 dB (Fig. 2). With initial diagnosis of acute suppurative otitis media, in order to relieve the severe pain myringotomy was done. After myringotomy, there was excessive bleeding. No pus was drained from the middle ear. CT scan of left temporal bone was done and it showed soft tissue density within middle ear and mastoid (Fig. 3). Intravenous antibiotics was given. But it was not much useful in relieving earache.

Fig. 2.

Preoperative pure-tone audiometry

Fig. 3.

CT temporal bone

Later MRI of temporal bone and brain was done to rule out any intracranial complication due to middle ear infection. It showed hypointense lesion in left epitympanum, mesotympanum and hypotympanum and mastoid air cells with normal ossicles and semicircular canals. MRV was normal (Fig. 4a, b and c). There was no evidence of sigmoid sinus thrombosis or any other intracranial complication.

Fig. 4.

a MRI T2. b MRI T2 Flair. c MRI T2 DWI

She underwent left cortical mastoidectomy and middle ear exploration under local anaesthesia. Antrum was filled with granulation tissue (Fig. 5a) and purulent discharge which was cleared and sent for histopathological examination. Erosion was noted over dural and sigmoid plate. and on elevating tympanomeatal flap, posterosuperior and posteroinferior quadrant of mesotympanum was filled with pinkish granulation tissue which was cleared. Ossicular chain (Fig. 5b) and aditus were engulfed with granulation tissue. Mastoid was well pneumatised. Complete exenteration of all aircells done. Extensive bleeding was noted during the surgery. Haemostasis was achieved after clearing the disease.

Fig. 5.

a Ossicles engulfed within the granulation tissue. b Granulation tissue within the mastoid antrum

Post operatively she had immediate resolution of symptom of pain. She received intravenous antibiotics, Meropenem 1 g TID and metronidazole 500 mg TID in the immediate postoperative period. Histopathology revealed acute and chronic inflammatory infiltrate, granulation tissue and numerous foci showing actinomycotic colonies (Fig. 6a and b). Following which she received oral Amoxycillin(500 mg) + potassium clavulanate(125 mg) twice a day, haematinics and multivitamins for 4 weeks. Gradually the demand for analgesics reduced and pain disappeared. At 2 months follow up external auditory canal and tympanic membrane were healed and epithelialized (Fig. 7) and she was symptom free. Postoperative Pure-tone audiometry showed improvement in hearing (Fig. 8).

Fig. 6.

Histopathology: Characteristic clumps of basophilic filamentous bacteria in a vaguely rosette-like configuration (arrow mark- sulphur granules containing actinomyces) surrounded by acute inflammatory infiltrate is seen. Acute inflammation is accompanied by dense fibrosis. Few areas of granulomatous inflammation are present

Fig. 7.

Postoperative appearance of tympanic membrane at 2 months of follow up

Fig. 8.

Postoperative pure-tone audiometry at 2 months follow up

Discussion

Middle ear actinomycosis typically affects children and young adults. Males are more frequently affected than females [3]. This case is reported in a 36-year-old female.

Three routes for contamination of the middle ear are possible, from the nasopharynx through the eustachian tube into the middle ear, directly through the external auditory canal and via the blood stream [4]. However as in our case it is not always possible to determine the source. Anaemia was a possible predisposing factor that contributed to the infection in this case. Other known predisposing factors are diabetes, malnutrition, alcohol use disorder and malignancy [5].

Patients often present with ear discharge [6], hearing loss [7], pain [8], facial weakness, paralysis [7] or even intracranial complications [9] in advanced cases. Middle ear actinomycosis can be difficult to diagnose due to its rarity and similarity to other middle ear infections. The symptoms are often nonspecific and the diagnosis is often made after excluding other possibilities. Middle ear actinomycosis should be differentiated from other middle ear infections like otitis media, cholesteatoma, and mastoiditis. In this case it mimicked like acute otitis media with a short history of 1 month, prompt evaluation when the disease was not responsive to usual treatment for acute suppurative otitis media and management with surgery enabled the cure with no complications [10]. Certain diagnosis from otoscopy alone is difficult. We find very often tympanic membrane with increased vascularity, red, pink or grey, sometimes bulging as was seen in this case or even with a perforation with eventual presence of granuloma or inflammatory polyps [11].

Imaging studies like CT and MRI can help in identifying the extent of the infection and detecting any complications like mastoiditis, intracranial spread or facial nerve involvement [12]. Due to severity of earache in this case, intracranial complication like lateral sinus thrombosis was suspected and hence she was also subjected to Magnetic resonance venography.

Histopathological examination of tissue samples is essential for diagnosing middle ear actinomycosis. The presence of actinomyces colonies and sulphur granules in the tissue confirms the diagnosis [13]. Treatment involves full surgical clearance in the form of mastoidectomy and long-term antibiotics [14].

There have been various regimens used in literature. Terry S. Olson, et al., reported a case where oral Penicillin V 250 mg 4 times daily for 6 months was used [15]. Valour F, et al., in their case report, used high doses of intravenous and then oral amoxicillin for 5 months [16]. PJ Kullar, et al., used oral amoxicillin for 6 months [17]. In a case reported by Mohammed Al Sheikh, et al., patient was started on amoxicillin and clavulanic acid 1 g and Doxycycline 200 mg/day [18]. Shagoon Modi, et al., prescribed a three-month course of oral amoxicillin [10]. G Gattaz, et al., used combined treatment with ampicillin with clindamycin [19]. In our case 1 month course of amoxicillin with clavulanic acid 625 mg BD for 4 weeks was adequate and patient was clinically normal at 3 months of follow up. One should always look for predisposing factors for the development of actinomycosis like in our case it is anaemia. Correction of anaemia by blood transfusion and haematinics possibly led to faster resolution of infection.

Conclusion

Middle ear actinomycosis is a rare and treatable condition. Early diagnosis and appropriate management are crucial to prevent complications and ensure a favourable outcome. It can present similar to acute and chronic otitis media. Predisposing factors should be corrected. Complete mastoidectomy by clearing all aircells is important in achieving cure.