Timothy C. Hain,
Last edited: 9-02
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Although BPPV accounts for the overwhelming majority of cases of positional vertigo, there are also other possibilities.
All of these entities are discussed elsewhere (follow the links) with the exception of central positional vertigo (CPV) and density disorders. CPV is a rare cause of positional vertigo, due to structural lesions in the cerebellum, especially the cerebellar nodulus and uvula. There are a number of potential causes -- CPV is nearly universal in persons with medulloblastoma, which is a tumor that arises in the cerebellar nodulus. CPV is also somewhat common in the Arnold-Chiari malformation and the related disorder of basilar invagination, and after strokes, tumors or multiple-sclerosis lesions involving the brainstem or cerebellum area. There are numerous rare cerebellar degenerations that can also result in central positional vertigo.
With respect to disorders in which there is a mismatch of endolymph and cupula density, the most commonly encountered is positional alcohol nystagmus (PAN). Commonly, when people imbibe a fair amount of an alcoholic beverage, they discover that upon lying down a strong vertigo ensues. This is caused by a difference in the rate that alcohol (which is lighter than water) enters the cupula of the inner ear compared to the endolymph. Similar syndromes occur in situations where the cupula is weighted down (e.g. cupulolithiasis), and perhaps also in situations where there is an alteration of the density of the endolymph by disease (i.e. Waldenstrom's macroglobulinemia, and perhaps autoimmune disorders). This possibility has not been considered in detail in the otologic literature.
Hearing has positional modulation to a lesser extent than does vertigo. Low-CSF pressure syndrome may cause hearing to be reduced on standing. It may be possible for people with gastroesophageal reflux to have reduced hearing on lying flat, as well as serous otitis media from reflux (Heavner et al, 2001; Tasker et al, 2002)
HEAVNER SB, Hardy SM, White DR, Prazma J, Pillsbury HC 3rd. Transient inflammation and dysfunction of the eustachian tube secondary to multiple exposures of simulated gastroesophageal refluxant. Ann Otol Rhinol Laryngol 2001; 110: 928-34.
Tasker A, Dettmar PW, Panetti M, Koufman JA, P Birchall J, Pearson JP Is gastric reflux a cause of otitis media with effusion in children? Laryngoscope 2002 Nov;112(11):1930-4
(c) 2000-2002 Timothy C. Hain