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Dizziness is any disturbed orientation in space, and dizziness must be differentiated from the sensation of blacking out or passing out known as syncope. Syncope is usually caused by vascular or central nervous system disorder. Vertigo is the sensation of whirling, of falling, or of some sense of motion. The patient feels that they are moving. They are not passing out, they are not going to faint. Those type of people have problems in their peripheral nervous system. The eyes, the statokinetic system (semicircular canals of the inner ear) and the appropriate receptive system. Not only just the soles of the feet but the muscle system as it goes up to the spinal cord. Those are the things that really have to all act in concert to orient yourself in space. If one of those three is out, you can probably compensate for it.
The central nervous system and the systemic system certainly open up a significantly larger work-up and we don’t have time to talk about that in 30 minutes. Again, remember the eyes, the inner ear and particularly the soles of the feet. That’s why so many diabetics have problems that they end up getting a little peripheral neuropathy and they have difficulty with the soles of their feet.
So one of the main things you want to talk about during your history is, "Do you have the sensation of falling or of movement?" that will certainly streamline your evaluation, and you need to look towards the eighth nerve in particular. Systemic abnormalities, you need to look more for cardiovascular and metabolic work-ups and you guys know how to do that, probably significantly better than I do.
Eustachian tube dysfunction and chronic otitis is sporadically reported as causing difficulties with the inner ear. It doesn’t usually give you true vertigo but often gives you the sensation of motion intolerance. More like being on a boat or a cruise ship than actually spinning. Trauma or iatrogenic injuries are pretty easy to pick up from the history. If they’ve had some form of surgery or car accident.
Tumors - even though they can be on the eighth nerve - acoustic tumors, meningiomas, cerebellopontine angle tumors usually don’t present with balance disturbance. They most of the time present with a unilateral sensorineural hearing loss, and that’s why we test the entire eight nerve complex
Nystagmus is one of the most important things that we are doing on the physical examination. Nystagmus is the movement of the eyes in relationship to the plane you are having to move in. It’s a rapid sensation one way and then a slow corrective phase the other way. The horizontal nystagmus - it’s just like calorics. If you remember the mnemonic COWS. Cold opposite, warm same. So if you have a lesion in the right ear the nystagmus is
The functional testing and the screening tests are a little bit different. The screening tests you probably have access to. The screening tests are audiograms and a urea test. Urea is just an osmotic diuretic that is given to patients and it’s helpful, really, in diagnosing two different diseases. One is Meniere’s syndrome. If you give urea and get multiple hearing tests over about a four hour period of time, the hearing and/or the discrimination.
Okay, this is from an actual disease standpoint and these are the things that you all will see. Meniere’s syndrome has definite criteria. If you use that definite criteria for the disease you’ll have a whole lot better success rate in treating these patients. I’ll talk to you about the medical treatment and certainly surgical treatment exists, but I see probably 20 to 30 Meniere’s patients a month and we only operate on probably one or two. So I mean, the necessity of operating on these patients is not that high. Benign paroxysmal vertigo, these are the two most common causes of vertigo.
This is the inner ear and this is why Meniere’s comes and goes quickly. This is Reissner’s membrane. This is the inner ear. The scala media which has a high potassium concentration and the scala vestibula, which has a high sodium penetration. As this fluid accumulates within the scala media, this membrane ruptures. It’s only one cell layer thick. As it ruptures you get the sodium and potassium mixture. It causes disruption of the organ of Corti. You get a hearing loss, it causes a vestibular weakness. As this one-layer thick cell heals, the ATP’s pump comes back into working, thems, we can operate on the systems, but once they have that diagnosis they’ll have it forever.
Attack prevention is the major way we go ahead and try and treat this. And salt prevention, diuretics, and a little mnemonic called CATS: avoid caffeine, alcohol, tobacco and either salt or stress. Stress being the same thing as fatigue. The harder these people work, the more tired they are, the more stressed out they are, the less inhibition the central nervous system can put on the vestibular system and they end up having more attacks. Conservative treatment is endolymphatic shunts. That preserves the hearing as well as the nerve. Very few labyrinthectomy’s are done anymore. In order to do a labyrinthectomy you need to have almost no useful hearing on that side. Because, by definition, when you do a labyrinthectomy you are making that person totally deaf for ever and ever. A vestibular nerve section spares the labyrinth so you can cut the vestibular nerve, preserve the cochlea so their hearing, although it may not be perfect, is still better than nothing. That’s certainly become the standard for what we do.
Benign paroxysmal vertigo is what we would want you to treat in your office after you’ve diagnosed it. Habituation exercises didn’t work. What happens is the patient just got better on his own. That’s the term benign. These patients do get better, some of them.