|Year : 2011 | Volume
| Issue : 1 | Page : 37-39
Facial palsy of unusual etiology - A diagnostic dilemma
Unnikrishnan K Menon, NV Deepthi
Department of ENT, Amrita Institute of Medical Sciences, Kochi, Kerala, India
|Date of Web Publication||11-Oct-2011|
Unnikrishnan K Menon
Department of ENT, Amrita Institute of Medical Sciences, Kochi, Kerala 682041
Source of Support: None, Conflict of Interest: None
Facial nerve paralysis is a common problem encountered in the ear nose throat out-patient department (ENT OPD). Impacted wax and its adverse effects in the external ear canal are also quite routinely seen. Rarely do the two come together in the same patient. We report a case of unilateral facial nerve palsy that presented an interesting diagnostic dilemma.
Keywords: Cerumen, Ear canal, Facial palsy, Keratosis
|How to cite this article:|
Menon UK, Deepthi N V. Facial palsy of unusual etiology - A diagnostic dilemma. Indian J Otol 2011;17:37-9
| Introduction|| |
Keratosis obturans (KO) is a condition in which desquamated keratinous material fills the deep external auditory canal (EAC). Toynbee first described this in a brief case report in the London Medical Gazette in 1850.  The characteristic clinical manifestations are severe otalgia and hearing loss due to accumulation of large plugs of desquamated keratin in the ear canal. There may be circumferential widening of the bony EAC, but no evidence of osteonecrosis or bony sequestration as is found in EAC cholesteatoma.  Facial palsy does not normally feature as a finding in these cases. We report an atypical, rare presentation of KO.
| Case Report|| |
A 35-year-old female was referred to our hospital for potential surgical management of facial palsy with corresponding ear complaints on her left side. She had a co-morbidity of hyperthyroidism. She presented in our casualty first. The history given was that of facial asymmetry on left side of about 15 days' duration. She also had associated vertigo since six days and vomiting since three days previously. There were also preceding symptoms of severe blockage and pain in her left ear for one month. This was followed by ear discharge which was reported as non-foul smelling and scanty.
Otoscopic examination revealed minimal blood-stained ear discharge on left side and a posterosuperior bulge. Tuning fork test was suggestive of a conductive hearing loss in the ear. Facial nerve examination revealed a grade 3 lower motor neuron (LMN) facial palsy on the left side.
High resolution computed tomography of temporal bone had been done elsewhere. This was reported as "showing moderate to severe left sided otomastoiditis with thickening of the wall of the left external auditory meatus. There was mild to moderate opacification of epitympanum without any intracranial extension. Minimal erosion of scutum and tympanic annulus was also seen. Ossicular chain was intact." Hence, a provisional diagnosis of left acute suppurative otitis media complicated by left LMN grade 3 facial palsy was made.
Patient was admitted and was given intravenous antibiotics and supportive measures. Routine preoperative work up was carried out. Thyroid stimulating hormone (TSH) value was abnormally low. In view of the facial palsy, vertigo and vomiting, neuromedicine consultation was sought. We counseled the patient and bystanders about the possible need for exploration and mastoidectomy to decompress the facial nerve and prevent development of any intracranial complications.
Next day, a detailed history and otomicroscopic examination rerouted the diagnosis as follows:
She had prior history of wax impaction with resultant symptoms of block and pain in her left ear one year earlier. She consulted a local ENT surgeon. Usual procedure of wax removal after the use of wax-softening drops had resolved the issue.
Present history was essentially a replica of the above symptoms at the outset. She delayed taking due treatment. Subsequently, she noticed some discharge, followed by onset of facial asymmetry. This apparently improved slightly over the next few days. She now consulted her local ENT doctor, who proceeded with the prescribed line of management for impacted wax. However, ear cleaning done a few days later was followed by vertigo and ear discharge. Ear block and pain was relieved fully, but facial asymmetry and minimal discharge persisted. There was also a mild decrease in hearing. There was no complaint of tinnitus.
There was a history suggestive of hyperthyroidism along with neck swelling.
Otomicroscopy revealed circumferential widening of external auditory canal with erosion of anterior, inferior, and posterior canal walls. There was a mild posteriosuperior bulge. Pars tensa was mildly retracted. There was no evidence of osteonecrosis or sequestrum formation. Examination of the other ear was normal.
Oto-endoscopy was also done using a rigid 30 degree nasal endoscope for the purpose of recording the findings [Figure 1].
|Figure 1: (a and b) Oto-endoscopic view of the left ear of the patient showing: A - Normal, intact tympanic membrane; B - Severely eroded inferior wall of the external ear canal; C - Erosion into the posterior canal wall|
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Tuning fork tests indicated a conductive hearing loss on left side.
Facial nerve examination revealed a grade 3 facial palsy of LMN type on left side.
Labyrinthine function tests were normal.
Pure tone audiogram showed 13 dB threshold on right side and 45 dB mixed hearing loss on left side.
Hence, the diagnosis was now modified to that of keratosis obturans resulting in bone erosion and pressure necrosis of the facial canal resulting in facial palsy.
Conservative management was continued with otomicroscopy and suction clearance, antibiotics, intravenous steroids, and other supportive measures. Her facial nerve function improved to grade 1.
Subsequently, she underwent uneventful thyroidectomy after achieving euthyroid status medically.
| Discussion|| |
The presence of a keratin plug occluding the deep external auditory canal was first noted and documented in the 19 th century. It has subsequently been proposed that two different diseases can be responsible for the presence of this type of obstruction within the deep meatus: keratosis obturans and external auditory canal cholesteatoma. 
The former is the accumulation of a large plug of desquamated keratin in the canal, while the latter is the invasion of squamous tissue from the ear into a localized area of bony erosion. 
The etiology of KO remains uncertain, although it has been related to eczema, seborrheic dermatitis and furunculosis, and even to bronchiectasis leading to reflex sympathetic nervous system stimulation of ceruminal glands and subsequent formation of an epidermal plug. The pathology is described as keratin plug occluding canal, thickening of tympanic membrane, ballooning up of ear canal, and hyperaemia of canal skin sometimes with granulations.
Patients with KO usually present with symptoms of severe pain, acute conductive hearing loss, and rarely, otorrhea. Signs include a widened ear canal with or without accumulated debris and a thickened tympanic membrane. Deafness and pain are usually secondary to accumulation of keratin in the ear canal.
Classic textbook description includes keratin or wax debris filling and packing the EAC, diffuse expansion of the deep EAC which becomes ballooned out with low ratio of depth to circumference and without any squamous epithelium deep to the debris. 
All the above features were noted in the present case.
Piepergerdes et al. described keratosis obturans as associated with a greatly widened ear canal due to circumferential erosion of bone.  Bony erosion in KO may be due to the pressure exerted by the silently accumulating mass of keratin in the EAC. In the case presented, there was extensive bony erosion in the anterior and postero-inferior segments, probably with exposure of the vertical portion of the facial nerve.
Literature search reveals sporadic reports of rare complications and presentations of KO. A case has been reported in which the principal symptom was a metallic taste and the main finding was extensive erosion of the hypotympanum with exposure of the facial nerve and the annulus of the tympanic membrane.  Fistulization of the horizontal semicircular canal, dehiscence of tegmen tympani and facial palsy have also been reported. , These complications and patterns of bone erosion have not previously been described in keratosis obturans. The latter case is believed to have been the most extensive case of keratosis obturans yet described.
Management options necessarily include epithelial plug removal under microscopy. Histological examination of any granulation tissue is required to exclude malignancy as the differential diagnosis includes carcinoma of the ear canal, necrotizing otitis externa, and benign bony sequestration in the external auditory canal.  Canalplasty has been suggested for recurrent KO with good results. 
The pathway of the facial nerve is long and relatively convoluted and so there are a number of causes that may result in facial nerve paralysis. Most common of these is Bell's palsy, an idiopathic disease that may be diagnosed only by exclusion. Others are trauma, herpes zoster oticus, acute and chronic otitis media and tumors compressing the facial nerve anywhere along its complex pathway. The latter could be facial neuromas, congenital cholesteatoma, hemangiomas, vestibular schwannomas, parotid gland neoplasms, or metastases of other tumors.
This case illustrates dramatically the atypical and extensive erosion that can occur in a neglected case of KO. Facial nerve dehiscence was produced by erosion of the posterior bony canal wall and adjacent mastoid air cells due to pressure exerted by the accumulating mass of keratin within the EAC. It emphasizes the importance of regular aural toilet in patients prone to this condition.
In our literature search, we could come across only two such documented cases; none being from Indian articles. We report this case both for its rarity as well as the initial diagnostic dilemma.
| References|| |
|1.||Toynbee J. Specimens of Molluscum Contagiosum developed in the external auditory meatus. Lond Med Gaz 1850;46:811. |
|2.||Persaud RA, Hajioff D, Thevasagayam MS, Wareing MJ, Wright A. Keratosis obturans and external auditory canal cholesteatoma: How and why we should distinguish between these conditions. Clin Otol 2004;24:577-81. |
|3.||Naiberg J, Berger G, Hawke M. The pathologic features of keratosis obturans and cholesteatoma of the external auditory canal. Arch Otolaryngol 1984;110:690-3. |
|4.||Lesser TH. Keratosis obturans and primary auditory canal cholesteatoma. In: Michael Gleeson, chief editor. Scott-Brown's Otolaryngology Head and Neck Surgery. 7 th ed. Vol 3. London: Hodder Arnold; 2008. p. 3342-5. |
|5.||Loock JW. Benign necrotizing otitis externa. In: Michael Gleeson, chief editor. Scott-Brown's Otolaryngology Head and Neck Surgery. 7 th ed. Vol 3. London: Hodder Arnold; 2008. p. 3334. |
|6.||Piepergerdes MC, Kramer BM, Behnke EE. Keratosis obturans and external auditory canal cholesteatoma. Laryngoscope 1980;90:383-91. |
|7.||Persaud R, Chatrath P, Cheesman A. Atypical keratosis obturans. J Laryngol Otol 2003;117:725-7. |
|8.||Saunders NC, Malhotra R, Biggs N, Fagan PA. Complications of keratosis obturans. J Laryngol Otol 2006;120:740-4. |
|9.||Glynn F, Keogh IJ, Burns H. Neglected keratosis obturans causing facial nerve palsy. J Laryngol Otol 2006;120:784-5. |
|10.||Paparella MM, Goycoolea MV. Canalplasty for chronic intractable external otitis and keratosis obturans. Otolaryngol Head Neck Surg 1981;89:440-3. |