Volume 6, Issue 4 , Pages 172-174, December 2011
Unilateral conductive hearing loss secondary to an ipsilateral high jugular bulb with contralateral agenesis of the lateral dural sinuses in a pediatric patient
Article Outline
Abstract
We present a case of a 7-year-old boy with a left sided conductive hearing loss accompanied by pulsating tinnitus. Otomicroscopic examination of the left ear revealed a bluish, non-pulsating mass behind the posterior inferior quadrant of the tympanic membrane. The audiogram demonstrated a left conductive hearing loss and a type B tympanogram. A myringotomy with insertion of a pressure equalizing (PE) tube was performed with no change in symptoms and hearing. CT demonstrated a high jugular bulb (HJB) on the left side, intruding the middle ear space, in contact with the ossicular chain. Venous stage of magnetic resonance demonstrated a complete dominance of the dural sinuses on the left side, with a huge internal jugular vein diverticulum. In addition, a complete agenesis of the lateral dural sinuses was demonstrated on the contralateral side. The combination of pulsatile tinnitus and unilateral conductive hearing loss with a red or blue to purple mass behind the tympanic membrane should alert the physician. Assessment of the anatomy and blood flow by CT scan and MRI of the ear and head are advised to delineate the finding, before considering any type of intervention.
Keywords: Otology, Audiology, Serous otitis media, Pressure equalizing tubes, High jugular bulb
1. Case presentation
A 7-year-old boy with no prior otologic history, presented to the otolaryngology service with left side hearing loss lasting for several months, accompanied by pulsating tinnitus exacerbated by effort. Otomicroscopic examination of the left ear revealed a bluish, non-pulsating mass behind the posterior inferior quadrant of the tympanic membrane.
The audiogram demonstrated a left conductive hearing loss with an air-bone gap of 25
dB (Fig. 1) and a type B tympanogram. There was no change on consequent audiograms. Assuming the diagnosis of serous otitis media, a myringotomy with insertion of a pressure equalizing (PE) tube was performed.
Fig. 1.
Audiogram of the child, at presentation. A conductive hearing loss with a 20–30
dB air-bone gap is exhibited on the left side. This was accompanied by a type B tympanogram.
Postsurgical follow up has not shown any change in symptoms or audiogram. High resolution computed tomography of the temporal bone (HRTBCT) (Fig. 2) demonstrated a high jugular bulb (HJB) on the left side, intruding the middle ear space and contacting the ossicular chain. Magnetic resonance venography (MRV) demonstrated complete dominance of the dural sinuses on the left side, with a huge internal jugular vein diverticulum. Additionally, the contralateral side showed complete agenesis of the lateral dural sinuses (Fig. 3).
Fig. 2.
High resolution temporal bone CT scans in the axial (a) and in the saggital plains (b). A high jugular bulb is demonstrated on the left side, intruding the middle ear space and in contact with the ossicular chain (arrows).
Fig. 3.
Cranial MRV demonstrating dominance of the dural sinuses on the left side, with a huge internal jugular vein diverticulum. Contralaterally – the right side demonstrates complete agenesis of the lateral dural sinuses. Parts (a) and (b) are in the axial and coronal plain, respectively, and part (c) demonstrates the coronal cranial and cervical view of venous vessels.
2. Discussion
A HJB is usually an incidental finding on HRTBCT and on magnetic resonance (MR) of the temporal bone. The finding is more common on the right side, since dural sinuses and the internal jugular vein are larger on the right side in the majority of the patients [1], [2]. Occasionally, significant bleeding may result from inadvertent puncture of a HJB during myringotomy, placement of a ventilation tube (VT) or during elevation of the inferior portion of a tympanomeatal flap. A fatal case of a myringotomy, which probably injured a high jugular bulb was first reported in 1914 [3].
When symptoms are present, conductive hearing loss (CHL) and humming tinnitus is commonly reported [2]. The CHL in the presence of a HJB may result from one or more of the following mechanisms: (1) Contact with the tympanic membrane. (2) Obstruction of the round window niche. (3) Interference with the ossicular chain [1], [2]. Weiss et al. [1] reported five patients with a reddish blue mass behind an intact tympanic membrane on otoscopic examination with unilateral conductive hearing loss, without pulsatile tinnitus. All patients underwent HRTBCT examination, confirming HJB. The authors stated that in none of their patients the hearing loss could be attributed to interference with the ossicular chain, but rather to contact of the jugular bulb with the tympanic membrane or round window niche obliteration. Haupert et al. [2] reported a patient with a HJB totally covering the round window, an intact ossicular chain, with a persistent conductive hearing loss of 40dB. In the current patient, the HJB was not in contact with the tympanic membrane, thus, obstruction of the round window and interference with the ossicular chain are the most likely causes of the CHL.
A HJB may appear as a white mass, resembling a cholesteatoma, when it is covered with bone. However, if the bony cover of the bulb is thin or dehiscent, a red or purplish mass may be seen, mistakenly referred as a glomus tumor. Additional conditions to be included in the differential diagnosis of a middle ear mass behind an intact tympanic membrane are: an aberrant internal carotid artery, persistent stapedial artery, cholesterol granuloma, and neoplasms involving the temporal bone [2].
HRTBCT delineates the bony anatomy of the temporal bone and clearly demonstrates HJB, however MR and MR venography are necessary to distinguish it from other vascular masses [1]. Reports on surgical correction of the CHL, include attempts to compress or relocate the HJB but have mostly been unsuccessful. Robin described a reposition of a high dehiscent jugular bulb compressing the ossicular chain and a consequent reconstruction of the floor of the mesotympanum by a cartilage graft. Postoperatively, the patient's hearing improved but deteriorated within time [4]. Glasscock described two cases of jugular bulb reposition and reconstruction of the floor with mastoid cortical bone graft with no postoperative hearing improvement in either case [5].
In the current case, any attempt to surgically manipulate the jugular vein would be especially dangerous since the left internal jugular vein exclusively drains the brain.
The combination of pulsatile tinnitus and unilateral conductive hearing loss with a red or blue to purple mass behind the tympanic membrane should alert the physician. Preoperative assessment should include HRTBCT in order to examine the exact anatomy of the temporal bone with complementary MR and MRV of the brain blood flow, to delineate the finding from other causes as stated above, and to demonstrate sufficient contralateral blood flow in the dural sinuses [6].
References
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- . Unilateral conductive hearing loss secondary to a high jugular bulb in a pediatric patient. Ear Nose Throat J. 1997;76(7):468–469
- . A case of probable injury to the jugular bulb following myringotomy in an infant ten months old. Ann. Otol. 1914;23:161
- . A case of upwardly situated jugular bulb in the left middle ear. J. Laryngol. 1980;186:1241–1246
- Vascular anomalies of the middle ear. Laryngoscope. 1980;90:77–88
- Surgical treatment of the high jugular bulb by compressing sinus sigmoideus: two cases. Eur. Arch. Otorhinolaryngol. 2008;265:987–991
PII: S1871-4048(10)00052-3
doi:10.1016/j.pedex.2010.07.002
© 2010 Elsevier Ireland Ltd. All rights reserved.
Volume 6, Issue 4 , Pages 172-174, December 2011
