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Dizziness and Benign Positional Vertigo |
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What is Benign Paroxysmal Positional Vertigo (BPPV)?
Benign Paroxysmal Positional Vertigo (BPPV) is an inner ear problem that results in short lasting, but severe, room-spinning vertigo.
Its name, BPPV, indicates that it is:
- benign, or not a very serious or progressive condition
- paroxysmal, meaning sudden and unpredictable in onset
- positional, because it comes about with a change in head position
- vertigo, causing a sense of room-spinning or whirling, often expressed as "dizziness".
Although called benign, those who suffer from this distressing and incapacitating condition do not trivialize BPPV.
Symptoms
BPPV often begins following head trauma or a severe cold. It can also arise simply as part of the aging process. It starts suddenly and is usually first noticed in bed, when waking from sleep. Any turn of the head seems to bring on violent but brief bursts of dizziness.
Patients often describe the occurrence of vertigo with tilting of the head, looking up or down (so called "top-shelf vertigo"), or rolling over in bed. It is not unusual for nausea and vomiting to accompany the vertigo. Even if a spell is brief, a feeling of queasiness may last several minutes or even hours.
There is no new hearing loss or severe ringing associated with these attacks, which helps to distinguish BPPV from other inner ear conditions.
Causes
To understand the cause of BPPV, it helps to understand how the inner ear works. The human ear is divided into three parts: the external, middle, and inner ear.
- The external ear consists of the part of the ear (the auricle) and the ear canal
- The middle ear includes the eardrum (tympanic membrane) and the three bones, or ossicles, of the middle ear, the malleus ("hammer"), incus ("anvil"), and the stapes ("stirrup").
- The inner ear is a fluid-filled series of chambers. One of these chambers, the cochlea, is responsible for converting sound vibrations into nerve impulses. It is these nerve impulses that the human brain interprets as sound and what we call "hearing."
The inner ear also contains 3 semicircular canals which are responsible, in part, for sensing movement and maintaining balance. These 3 canals (named anterior, lateral, and posterior) are oriented at roughly right angles to one another. The movement of the fluid within these canals allows the brain to sense rotation of the head through all three directions in space (e.g. left-right, forward-back, and up-down). All 3 canals are connected to a large chamber, called the vestibule.
The probable cause of BPPV is dislodgement of small calcium carbonate crystals that float through the inner ear fluid and strike against sensitive nerve endings (the cupula) within the balance apparatus at the end of each semicircular canal (the ampulla).
These crystals, known as otoconia, usually dissolve or fall back into the vestibule within several weeks, and no longer cause any symptoms. However, in some patients, these crystals become trapped in the fluid of the balance chamber and periodically cause symptoms, as gravity and head movements cause them to repeatedly strike against the cupula. In these patients, the symptoms may not subside and they become severely incapacitated.
Interestingly, the loose otoconia tend to settle preferentially within the posterior semicircular canal. This is because the posterior canal hangs down like the water trap in a drain pipe, allowing the crystals to settle in the bottom of the canal.
Diagnosis
The most important means for diagnosing this condition is the physical examination and history of the patient. A patient with dizziness or vertigo without hearing problems suggests the diagnosis of BPPV. A normal ear exam, audiogram, and neurological exam are expected. A simple positional test, performed in the doctor's office, is usually all that is needed to confirm the diagnosis of BPPV.
- One such test is the Dix-Hallpike test. First, the patient is positioned on the examining table, seated upright. Then the examiner brings the patient's head down over the edge of the table and turns the head to one side. If the patient has BPPV, the examiner will witness a characteristic movement of the eyes, call nystagmus, that begins after a few seconds.
If the nystagmus is seen and the patient becomes dizzy, then the ear which is pointing toward the floor is the one with the loose otoconia. If no nystagmus is seen the examiner will repeat the test, this time turning the head to the opposite side, thus testing the other ear.
This nystagmus and perception of vertigo will slow down and cease after 15 to 20 seconds. If the head is not moved, no further symptoms will occur. When the patient sits back up, the dizziness will recur, but for a shorter period of time. Lying down on the opposite side will not cause the vertigo.
Occasionally, in order to confirm the extent of the inner ear dysfunction, an electronystagmogram (ENG) will be ordered.
Read about treatment options for BPPV
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