Teaching Case

A 83-year-old man presented with sudden onset of hearing loss in the right ear followed by tinnitus and vertigo after two days, without any other symptoms. As significant previous history he had undergone aortic valve replacement surgery five years ago and was on anticoagulation therapy. Coagulation tests showed increased prothrombin time and activity. Other laboratory findings were normal.

Tinnitus and vertigo subsided within a few days. Hearing loss improved only partially.

Axial and coronal magnetic resonance imaging showed a hyperintensity affecting the cochlea and the vestibule in the precontrast T1-weighted images, with no significant enhancement on postcontrasted T1-weighted images. This signal could be explained by the presence of lipid, haemostasis, high protein concentration and haemorrhage. Given the previous medical history, the rapid symptoms onset and the corresponding hypointensity seen on T2-weighted images, bleeding was suspected.

The patient was prescribed to stop the anticoagulation therapy to reduce the risk of ongoing haemorrhage and high dose prednisolone was added.

Follow-up MRI showed complete resolution of the previous findings.

Sudden sensorial hearing loss (SSNHL) is defined as a sensorineural audiometric loss of 30 or more dB within not more than 72 hours and consecutively over three pure tone frequencies [1].

SSNL is typically unilateral and may be sudden or rapidly progressive, partial or complete and improves spontaneously in 65% of patients within two weeks. About 85% of the SSNHL are idiopathic and managed with empirical treatment [2].

Intralabyrinthine haemorrhage (ILH) is a rare cause of SSNHL.
In most cases, the aetiology of ILH remains unclear, but has been associated with anticoagulant therapy, hypertension, haematologic disorders (coagulopathies, sickle cell anaemia, pernicious anaemia, leukaemia), trauma (head trauma, barotrauma or local surgery) endolymphatic sac tumours and labyrinthitis (viral, bacterial, postoperative or autoimmune, the latter bilateral and often with other systemic involvement) [3].
Clinical diagnosis of ILH is very difficult and has to rule out many differential diagnoses such as labyrinthine hydrops or Menière’s disease, non-haemorrhagic labyrinthitis, cochleovestibular neuritis and schwannoma, labyrinthine fistula and ischaemia of the internal auditory artery.

MRI is a very helpful and initial diagnostic tool in the evaluation of SSNHL [4].
In T1-weighted images, the perilymph and the endolymph are normally isointense to the cerebrospinal fluid. The typical precontrast T1-hyperintensity seen in ILH in the cochlea, vestibule and/or semicircular canals is due to the meta-haemoglobin found during subacute period within normally fluid-filled space of labyrinth. Because this T1 hyperintensity could also be explained by the presence of fat seen in the uncommon intralabyrinthine lipoma, fat-suppressed T1-weighted images may be used to distinguish both entities, particularly in cases of atypical clinic presentation without abrupt onset of the symptoms. T2-images can be variable in ILH according to the haemorrhage stage but, like in our case, are useful to differentiate ILH from the rest of entities that appear typically hyperintense on T1-weighted images. In cases of SSNHL due to acute labyrinthitis, enhancement of the labyrinth on post-contrast T1-weighted images would be expected.

Because of the high percentage of spontaneous cure, treatment of SSHL remains controversial. Treatment options include removal of the predisposing cause and oral or intratympanic steroid treatment. Cochlear implant is an option for some patient as definitive therapy for hearing loss

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