Clinical Balance Disorders
The differential diagnosis of dizziness or vertigo is difficult, because it can involve multiple disorders. The most critical component of the examination is a careful inquiry into the patient's symptoms.
Patients typically describe their symptoms in one of four ways:
Dizziness when assuming an upright posture: Presyncope--light-headedness or a sense of imbalance when sitting or standing up--typically indicates either (1) carotid or vertebrobasilar obstruction secondary to atherosclerosis, (2) dysautonomia secondary to antihypertensive or antiarrhythmic therapy, or, (3) rarely, primary dysautonomia, such as Shy-Drager syndrome.
An inability to maintain balance: Patients may associate this sensation with dizziness or vertigo, when actually it represents ataxia.
Vague sensation of imbalance or dizziness: When an organic cause is not obvious, and particularly if patients are unable to describe symptoms with specificity, this sensation may indicate a psychogenic problem associated with panic disorder and anxiety.
It feels like the room is spinning: Vertigo, a sensation that the environment is moving when it is not, may be of either central (brainstem or cerebellum) or peripheral (inner ear or vestibular nerve) origin.
Presyncope can often be elicited simply in the examining room or, if not, using a tilt table. Transcranial Doppler echocardiography or magnetic resonance angiography of the neck can be used to identify or rule out a stenotic lesion.
Gait abnormalities should be evident when observing the patient. Differential diagnosis of ataxia requires consultation with a neurologist.
Psychogenic dizziness may be frustrating to diagnose because no organic cause can be found and the patient cannot describe the symptoms in a systematic way. However, symptoms can often be reproduced with hyperventilation. Some physicians order tests such as electronystagmography, as much to reassure the patient as themselves.
Benign positional vertigo can be confirmed by the Dix-Hallpike (or Bárány) maneuver. This consists of moving the patient from a sitting to upright position, with the head turned and hanging over the head of the bed or table so that the affected ear faces the floor.
Episodes of vertigo that last for hours, accompanied by fluctuating and progressive sensorineural hearing loss and tinnitus, strongly suggest Ménière disease. Vertigo that lasts for hours but is not associated with significant auditory symptoms is usually migrainous in origin.
Vestibular neuronitis is characterized by an acute onset of vertigo associated with nausea and vomiting, but no symptoms of auditory or CNS dysfunction. This relatively benign disorder is distinguished from other neurovestibular abnormalities (such as a tumor or inflammation due to an infection) by a lack of associated symptoms, the absence of dysdiadochokinesia, and the fact that symptoms do not recur.
Treatment of presyncope involves addressing the underlying stenosis or adjusting medication.
Psychogenic dizziness should be addressed as an anxiety disorder.
The treatment of Meniere disease is controversial, because of the high potential for an initial placebo effect and the risk of aggravated hearing loss with long-term use of medical treatments such as vestibular suppressants.
Neurovestibular abnormalities are treated by eradicating the causative infection or treatment of the underlying malignancy.
- ↑ [http://www.consultantlive.com/display/article/10162/37839 Ruckenstein MJ. The Dizzy Patient: How You Can Help. Consultant Feb. 1, 2006]