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Vertigo

The term vertigo means different to different people. “Vertigo” is often used in a confusing way by people. The term vertigo is misused by patients and press to convey heaviness in the head, a sense of imbalance while walking without actual falls or it may mean light headedness. Some people use the word for fainting, unconsciousness or even a true convulsive seizure. The misquote of vertigo is further propagated by the movie Vertigo which is not in fact about true vertigo, it is about agoraphobia. The true medical meaning of vertigo is a sense of rotation of self or the surrounding. It is a hallucination (false feeling) of rotation.

Vertigo by itself is not a disease. It is a symptom of an underlying disease. It is a symptom like fever which has several different causes. Commonly diseases of the inner ear cause vertigo. These are usually not life threatening but are disabling. As opposed to these, diseases of the nervous system causing vertigo could be serious. The common diseases with vertigo as a presenting symptom are benign paroxysmal positional vertigo, vestibulitis, and post traumatic vertigo. The nature of the symptoms accompanying vertigo and the duration of symptoms helps to know the correct cause of vertigo. Ear diseases causing vertigo are almost always not accompanied by other neurologic symptoms. Nervous system related causes which are more serious are almost always accompanied with other neurological symptoms and signs.

Benign paroxysmal positional vertigo (BPPV)
BPPV is a common cause of vertigo. About 20% of all vertigo is due to BPPV. Benign paroxysmal positional vertigo (BPPV) is a condition characterized by episodes of sudden and severe vertigo when the head is moved around. The vertigo typically lasts for second and usually less than a minute. The vertigo is precipitated by a particular position of the head (semicircular canals). Common triggers include rolling over in bed, turning in the bed, getting out of bed, and lifting the head to look up. An affected person may have attacks of vertigo for a few weeks, then a period of time with no symptoms at all. Usually BPPV affects only one ear commonly the right ear. It is thought that BPPV is caused by particles (calcium crystals called as debris) within the balance organ of the inner ear. Other names for BPPV include benign postural vertigo, positional vertigo and top shelf vertigo (because you get vertigo on looking up).

Symptoms
The symptoms of BPPV include dizziness or vertigo, lightheadedness, imbalance, and nausea.
The symptoms of BPPV are:
- Sudden episodes of violent vertigo
- Nausea
- The vertigo may last half a minute or so
- The eyes may drift and flick uncontrollably (nystagmus)
- Movements of the head trigger the attacks

All these symptoms may not be seen in a particular patient and variation in presentation is common.

Etiology
Inside the inner ear is a series of canals filled with fluid. These canals are at different angles to each other. These canals detect the exact position of head and movement of the head. When the head is moved, the rolling of the fluid inside these canals tells the brain exactly how far, how fast and in what direction the head is moving. BPPV is thought to be caused by small calcium carbonate crystals/debris (otoconia) within the canals. Usually, these crystals are held in special reservoirs within other structures of the inner ear (saccule and utricle). It is thought that injury or degeneration of the utricle may allow the 'ear rocks' (the crystals) to escape into the balance organ and interfere with the fluid flow.

Factors that may allow calcium carbonate crystals to migrate into the balance organ include:
- Head injury
- Ear injury
- Ear infection, such as otitis media, viral infections
- Ear surgery
- Degeneration of the inner ear structures
- Vestibular neuritis (viral infection of the inner ear)
- Meniere's disease (disorder of the inner ear)
- Some types of minor strokes
- In around half of BPPV cases, the cause can't be found (idiopathic BPPV).

Diagnosis
Since vertigo can be a symptom of a serious brain disorder a careful history and examination is required for diagnosis of BPPV.
- Medical history-illnesses such as cardiac arrhythmia, low blood pressure and multiple sclerosis can include symptoms of vertigo.
- Physical examination-The patient lies on the examination bed while the doctor deliberately moves their head into positions that are known to trigger BPPV within a few seconds. The doctor will also check for positional nystagmus.
- Electronystamography (ENG)-a special eye test that checks for the presence of nystagmus.
- Ear tests-such as hearing tests.
- Imaging-magnetic resonance imaging, to check for the presence of other Neurological disorder (Brainstem, cerebellum) which can cause vertigo.

It should be noted that BPPV is a diagnosis of exclusion since nervous system disorders could cause symptoms similar to BPPV. Hence these disorders should be excluded by proper evaluation by a neurologist and MRI scan of the brain when appropriate.

Treatment
Generally, BPPV resolves by itself within six months or so. The patient could get recurrent attacks and vertigo can recur for a long time in some patients. Treatment options in the meantime could include medications to help control vertigo. These are betahistine and vestibular sedatives in case of incapacitating vertigo. Special maneuvers (canalith repositioning) designed to dislodge otoconia is the specific treatment of BPPV. These maneuvers have an 80 per cent success rate:
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The Semont maneuver-In this the patient lies down, then is quickly rolled from one side to the other.
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The Epley maneuver-This is also known as the typical canalith repositioning procedure. The patient's head is moved into four different postures. The head is held in each posture for about half a minute.

These maneuvers can be done in the office, with instructions to be followed at home.