Published in the May 2009 issue of Today’s Hospitalist
When a patient complains of acute dizziness, what’s the first question you should ask? According to S. Andrew Josephson, MD, director of the neurohospitalist program and assistant professor of neurology at the University of California, San Francisco (UCSF), your automatic response should be, “What do you mean by ‘dizzy’?”
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How patients answer that question, he explained, can give you key information. First, it can help you decide whether the problem is likely to be syncope or vertigo. And the answer, along with a careful history and exam, will let you localize the cause of vertigo and determine whether it is peripheral or central.
At UCSF’s annual hospital medicine conference last fall, Dr. Josephson acknowledged that patients who present with vertigo can be very frustrating. “It is an extraordinarily nonspecific complaint,” he admitted.
When trying to diagnose a central cause of vertigo, think of the three “Ds” of brainstem dysfunction: dysarthria, dysphagia and diplopia.
During his presentation, however, Dr. Josephson out- lined a practical approach to working up vertigo that is designed to help hospitalists feel more comfortable making a diagnosis.
Forget textbook distinctions
According to Dr. Josephson, physicians shouldn’t get hung up on distinctions that are often stressed in textbook discussions of vertigo. Those won’t help much with actual patient care.
A good example is struggling to determine if patients have “disequilibrium,” dizziness described as feeling like they just got off a carousel or a boat as opposed to true room-spinning vertigo. “Put every patient you used to think of as having disequilibrium into the vertigo category,” Dr. Josephson recommended. “A lot of these patients have central causes of vertigo.”
Dr. Josephson also urged physicians to broaden their definition of vertigo. Patients who describe the room as spinning or themselves as spinning in relation to the room are only a minority of those with the condition. Instead, he argued, doctors should think of vertigo more broadly as any “dissociation between the patient and their environment,” whether it’s rocking, falling, swaying or having any sense of movement.
“If you are just defining vertigo patients as those who say the room is spinning, you are missing a lot of patients with vertigo,” he pointed out. “That’s when we tend to get into trouble, because vertigo can have a number of serious causes.”
It’s also important to realize that “dizziness” has different connotations in different cultures, a point that was hammered home when Dr. Josephson saw a patient in the ED complaining of dizziness. It turned out that her dizziness was actually “crushing substernal chest pain.” In her culture, he said, “dizziness just meant an overall feeling of unwell.”
Syncope vs. vertigo
During your initial exam, keep in mind that as many as one-fifth of patients who present with syncope or presyncope say they feel dizzy.
“Presyncopal symptoms are, of course, the key,” said Dr. Josephson. “Those include color change, light-headedness and tunnel vision.” He also pointed out that witnesses who see patients experiencing syncope often report seizure-like movements, with shaking of all four limbs. That’s because myoclonic jerks are a typical accompaniment of syncope.
Once you rule out syncope, you need to find out whether the cause of the vertigo is central or peripheral. Patients with central vertigo need central nervous system imaging; those with peripheral etiologies do not. The problem with making that distinction, however, is that many symptoms are the same for people presenting with either type. These include vomiting, nausea, inability to walk, nystagmus and an inability to sit upright without falling to one side. None of these reliably distinguishes central vs. peripheral vertigo.
Because peripheral vertigo is often caused by inner-ear problems, the following symptoms usually indicate a peripheral cause: hearing loss, tinnitus, symptoms of pain or fullness in the ear, and symptoms that occur only when patients turn their head.
But because the nuclei of most cranial nerves are housed in the brainstem, any cranial nerve abnormality with vertigo should point to a central cause. “Think of the three ‘Ds’ of brainstem dysfunction: dysarthria, which is slurred speech; dysphagia, meaning you can’t swallow; and diplopia, or double vision,” Dr. Josephson said. “If patients present with slurred speech and vertigo, for example, assuming that the slurred speech isn’t from the anti-emetics the ED physician gave them, that’s a brainstem problem.”
An accompanying headache may make it “more likely” that the cause is central, not peripheral, he pointed out, but both types of vertigo can include headache. Older age and the presence of vascular risk factors also make central vertigo more likely.
“Demystifying” the nystagmus exam
The nystagmus exam can help you separate central vertigo from peripheral. Unfortunately, the exam “is a black box for everyone: neurologists, ENT and medicine doctors included,” Dr. Josephson said. “Let me demystify it.”
Nystagmus is the to-and-fro eye movement that has both a slow and a fast phase. If nystagmus fatigues with time, goes away with fixation, starts after a five- or 10-second delay, is always in the same direction, or is torsional, the vertigo is likely to be peripheral. With central vertigo, eye movement changes direction depending on which way the patient is looking and will tend to start immediately.
One common mistake, said Dr. Josephson, is thinking that vertical nystagmus “which is an indicator of central vertigo “means there is nystagmus when somebody looks up or down. “With vertical nystagmus, the actual nystagmus is up and down,” he said.
Twisting (torsional) nystagmus indicates benign paroxysmal positional vertigo (BPPV). Physicians have a harder time seeing twisting nystagmus when patients have dark irises, but Dr. Josephson recommended that hospitalists practice recognizing it.
He also said to pay attention to any signs of cranial neuropathy or of asymmetrical cerebellar findings. Those include poor results from a finger-nose-finger exam on only one side.
BPPV, which is the most common cause of peripheral vertigo, is thought to be caused by calcium carbonate crystals getting caught in the posterior semicircular canal, leading to an acute plunger effect. It usually comes on suddenly; is precipitated by a change in head position; is a common cause of dizziness in the elderly as well as in patients of any age; and it often recurs.
Dr. Josephson prefers to diagnose BPPV by an ocular exam and watching nystagmus, but sometimes he finds he needs to do a Dix-Hallpike maneuver as well. Treatment is the Epley maneuver. Performing the Epley maneuver ” and teaching it to patients to do on their own if BPPV recurs “”is one of the most rewarding treatments in all of neurology” because it works so quickly.
The second most common cause of peripheral vertigo is vestibular neuronitis, also known as vestibular neuritis or, if accompanied by hearing loss, labrynthitis. While this type of vertigo is often chalked up to a virus, Dr. Josephson said that a history of preceding viral infection is found only half the time.
Vestibular neuronitis can get worse over one to three days and then slowly improve; in some cases, however, that can take months. Thanks to a study published in the July 22, 2004, New England Journal of Medicine, a treatment for these patients now exists: steroids. Although the study tested a regimen that included very high doses of steroids, multiple regimens are commonly used.
Other causes of peripheral vertigo have a specific treatment. Meniere’s disease, for instance, can be treated with a low-salt diet or diuretics.
About a third or more of patients with migraine will have vertigo as part of their spell. Although there are no real data to back up the prescription, Dr. Josephson said that many headache specialists treat vertiginous migraine with acetazolamide (Diamox) or verapamil.
Other peripheral causes to keep in mind, he said, are autoimmune inner ear disease; ototoxic drugs like gentamicin; infections like syphilis, which is on the rise; and mastoiditis.
Most peripheral vertigo will pass with time “because the brain learns to deal with the differential signals coming from both ears,” he said. As a result, Dr. Josephson said, he neither likes to prescribe commonly used medications like Valium that work by putting people to sleep nor put the patient on bed rest.
“That slows down this compensation process,” he said. “As long as patients are safe and aren’t going to have a fall, I encourage people to mobilize early, even if it is just sitting up in bed.” That allows the brain, he explained, “to more quickly reset the set point.”
Any patient you suspect has central vertigo, Dr. Josephson said, should be sent for neuroimaging. Since CT is poor for looking at the posterior fossa, MRI is usually necessary.
Vertigo accompanied by any cranial nerve lesion should be considered a basilar artery thrombosis until proven otherwise. Basilar artery thrombosis is an important diagnosis to make because if left untreated, it is nearly always fatal. The diagnosis is made with either MRA or CTA; acute stroke therapies such as mechanical embolectomy have been shown to be successful for this condition in non-randomized series out to 12 or even 24 hours after onset.
Another potentially deadly cause of central vertigo is cerebellar ischemic stroke. Because the posterior fossa is rigid, cerebellar strokes can lead to brainstem herniation, typically within three to five days.
Patients may be sent home from the ED looking relatively well with an incorrect diagnosis of peripheral vertigo, only to return days later in coma. The key to detection, said Dr. Josephson, is any asymmetry in the cerebellar examination; bilateral cerebellar abnormalities on exam are usually metabolic in origin. An MRI will show the stroke where CT will not.
Once identified, these patients need to be monitored closely for deterioration and then taken for life-saving posterior fossa decompression, should swelling and decompensation occur.
Deborah Gesensway is a freelance health care writer based in Sierra Madre, Calif.
How to interpret a nystagmus exam
BECAUSE PATIENTS CAN HAVE NYSTAGMUS with almost any type of vertigo, S. Andrew Josephson, MD, director of the neurohospitalist program and assistant professor of neurology at the University of California, San Francisco, offered this guidance for how to interpret nystagmus and what interpretations mean in terms of being caused by central or peripheral vertigo:
1. Patients have nystagmus when they look to the right. But as they continue looking to the right, the nystagmus stops after a few seconds.
2. Patients have rapid nystagmus looking off into space. However, when you ask them to stare at your fingers right in front, the nystagmus goes away.
3. When patients look to the right, there is right-beating nystagmus. When they look to the left, there is left-beating nystagmus.
4. When patients look to the right, there is no nystagmus. But it starts after five or 10 seconds.