Tullio phenomenon and drop attacks – An unsuspected cause

Abstract

Tullio phenomenon or loudness intolerance is most commonly associated with superior semicircular canal dehiscence. We describe a patient presenting solely with this phenomenon and found to have an unsuspected cause. A 43-years-old gentleman presented to us complaining of intolerance to loud noise, occasionally leading to falls, for six months. These complaints were insidious in onset and steadily progressing. Interestingly, the intolerance in heavy traffic used to subside on wearing a helmet. There was no history of hearing loss, tinnitus, earache, or ear discharge. Clinical tests of hearing including Rinne, Weber and absolute bone conduction test were within normal limits. The neurologic as well as systemic examination was normal. Pure tone audiometry (PTA) showed mild conductive hearing loss in left ear and brainstem auditory evoked response (BAER) was normal. Patient’s skull radiograph showed multiple large lytic lesions giving the appearance of “geographical skull”. Chest X-ray showed a lytic lesion with pathological fracture involving posterior part of in left sided rib. Computed Tomography of head with bone window also showed multiple lytic lesions in skull (Figure 1,2). Brain parenchyma was normal. Incisional biopsy of one of the skull lesions was performed, which was consistent with a diagnosis of Langerhans cell histiocytosis (LCH) (Figure 3). The patient showed considerable improvement after being initiated on Etoposide and Vinblastine. LCH is a rare cause of Tullio phenomenon. It appears that the loss of skull tissue due to lytic lesions leads to impairment of “modifier” function of intact skull, resulting in “volume conduction” and noise intolerance.