Dizzying new perspectives of vertigo research
By Béla Büki
In the last three decades vertigo science has been revolutionized by new examination techniques and improving understanding of physiological principles. It used to be the case that a great percentage of patients with vertigo and dizziness did not receive any definite diagnosis; today not only has this ratio improved dramatically but in the majority of cases an effective therapy may be started. This changed neurotology, a speciality bordering between ENT and neurology, from a field of frustrations to a source of success. This is valid even in general practice because many of the bedside tests and simple treatments are easy to learn and do not require any sophisticated, expensive apparatus.
When dealing with vertigo or dizziness, there may be acute cases and chronic recurrent complaints. In vertigo as emergency, the most urgent task is to identify the most dangerous, perhaps life threatening causes. In chronically recurrent vertigo, the patient may not have complained about it when seeing their doctor, which makes it difficult to find the cause and apply effective treatment.
Ten highlights from recent developments
1. Acute vestibular syndrome (acute dizziness lasting more than 24 hours) is most frequently caused by peripheral, viral vestibular neuritis or central ischaemic stroke in the brainstem or cerebellum. Superficially, they may present themselves in very similar ways. The differential diagnosis between the two is easy: a simple bedside examination consisting of the head impulse test – searching for direction changing nystagmus and/or vertical misalignment of the eyes – reliably identifies stroke in acute vestibular syndrome.
2. According to the latest literature, the quality of vestibular complaints (e.g. rotating vertigo, unspecific dizziness or imbalance) does not seem to be helpful in making the diagnosis, because in a clinical setting the descriptions of the quality of dizziness are unclear or inconsistent and therefore unreliable.
3. Benign paroxysmal positional vertigo, which is caused by dislocated otoconia, may be even more frequent than previously thought, because it may occur in many cases without the characteristic, repetitive eye movements (nystagmus) which are otherwise provoked by head position changes.
4. If, in benign paroxysmal positional vertigo (BPPV), otoconia are not glued to the cupula but instead move freely in the posterior canal then they can be flushed out by a special sequence of movements (equivalent to a backward somersault in two phases). This is also possible when the horizontal canal is involved. Then a horizontal sideways roll, the ‘barbecue roll’, seems to be the most effective treatment.
5. Recently it has been suggested that vitamin D deficiency may be connected to repetitive exacerbations of BPPV and that vitamin D supplementation may possibly decrease the frequency of recurrences.
6. There is a new treatment for Menière´s disease, which has been proven to be more effective than placebo: a single intratympanic gentamicin injection, which stops the attacks by a mild inhibition of the responsible vestibular organ. This is especially good news, since otherwise the frequent, severe attacks may make normal life impossible.
7. With the new quantitative video-based head-impulse testing now available, the function of individual semicircular canals can be assessed reliably in an everyday clinical setting. This, together with vestibular evoked potentials, provides a powerful tool to assess all parts of the peripheral vestibular organs with a high resolution.
8. In the last few years, vestibular migraine, the “chameleon” of vertigo disorders emerged as a possible cause of, sometimes severe, vertigo and headache when no other central pathology can be found.
9. In the relatively recently discovered ‘labyrinth dehiscence syndrome’, a third window opens on the labyrinth in the direction of the intracranial space. This explains several, sometimes bizarre complaints, such as pressure-induced vertigo or when patients hear noises from their own body: ‘Doctor, I hear the movements of my eyes!’ Since the condition causes an apparent middle-ear hearing loss but without any pathology in the middle ear, otologists now better understand cases with pseudoconductive hearing loss, when ear operations cannot improve hearing.
10. Idiopathic chronic bilateral vestibular hypofunction (chronic vestibular insufficiency) may frequently cause constant dizziness in the elderly or after ototoxic antibiotic/cytostatic therapy. The diagnosis is easy, because the head impulse test is highly pathological, standing on foam with the eyes closed triggers falls, and the patients´ ability to read during head shaking decreases.
In conclusion, with all these new developments, it is certainly worthwhile to take time with vertigo patients. New syndromes explain mysterious complaints better; new, effective therapies bring relief more often than before. As G. Michael Halmágyi put it: “with some understanding of basic vestibular physiology, it is now possible, in my view, to make a reasonable diagnosis on history and examination in about 80% of dizzy patients … and to be able to treat successfully about 80% of them.”
Together with Alexander A. Tarnutzer, Béla Büki is the author of the Vertigo and Dizziness, a title in the Oxford Neurology Library. He is working as an otolaryngologist and neurotologist in Krems an der Donau, Austria. His special areas of scientific interest are fluid pressure increase inside the labyrinth and in the intracranial spaces and benign paroxysmal positional vertigo together with its variants without nystagmus.
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