Common Vestibular Disorders
Benign Positional Vertigo
Benign positional vertigo, believed to be the most common type of peripheral vertigo, can be seen following head injury, vestibular neuronitis, stapes surgery, Meniere’s disease, or can present alone. The disorder is thought to be related to an abnormality in the association of the otoconia to the cupula within the membranous labyrinth, resulting in abnormal responses to endolymph movement with head motion. Symptoms are typically associated with head movement, such as rolling over or getting in or out of bed. The associated vertigo is brief, lasting only seconds in duration, and can be seen as an acute form only or in an intermittent or chronic form.
Labyrinthine Infarction
Labyrinthine infarction leads to a sudden profound loss in auditory and vestibular function, and typically occurs in older patients. This phenomenon can be seen in younger patients with atherosclerotic vascular disease or hypercoagulation disorders. Episodic vertigo may herald a complete occlusion in the form of a type of transient ischemic attack. After complete occlusion, the acute vertigo that ensues will subside, often leaving the patient with some residual unsteadiness and dysequilibrium over the next several months while vestibular compensation occurs.
Vestibular Neuronitis
Vestibular neuronitis presents as a sudden episode of vertigo without hearing loss in an otherwise healthy person. The disorder can occur as a single attack or can present as multiple attacks. It occurs more often in spring and early summer, and as a result is often associated with an upper respiratory tract infection developing around the same time. The onset of vertigo is sudden and is typically associated with nausea and vomiting, and can last for a period of days with gradual improvement over the following weeks. The disorder is often followed by episodes of benign positional vertigo.
Labyrinthitis
Labyrinthitis is an inflammatory process occurring within the membranous labyrinth that may have a bacterial or viral etiology. Viral infections produce symptoms of dizziness similar to vestibular neuronitis, except that there is cochlear dysfunction as well. Congenital measles, rubella, and cytomegalovirus infections frequently cause no vestibular symptoms. Bacterial labyrinthitis can present in a supparative form with direct involvement of the membranous labyrinth by the pathogen, or in a serous form. The serous form often is seen with acute otitis media when diffusion of bacterial toxins across the round window membrane occurs.
Meniere’s Disease
Meniere’s disease is an inner ear disorder characterized by episodic vertigo attacks, sensorineural hearing loss, tinnitus, and pressure or fullness in the involved ear. Initially, the hearing loss involves the lower frequencies and fluctuates, usually worsening with repeated attacks. The attacks are characterized by true vertigo, usually with nausea and vomiting lasting hours in duration. Histopathologically, this disorder is believed to be due to dilation of the endolymphatic spaces (hydrops) with ruptures and subsequent healing of the membranous labyrinth. Variants of the disease do occur, including vertigo without associated auditory symptoms.
Migraine
The vast majority of migraine variants are made up of the first two categories, migraine without aura, and migraine with aura. The term aura can be defined as a focal neurological disorder. Auras generally are considered to be abnormal sensory perceptions. Visual auras are the most frequent type, and may come in a wide variety of phenomena or hallucinations.
It is valuable for healthcare professionals to have at least a basic understanding of migraine and audiovestibular symptoms. Vertigo, tinnitus, photophobia, and phonophobia, and occasionally hearing loss may present in at least 30% of migraine patients.
Although hearing loss in migraine patients is less common than in vertigo, tinnitus, photophobia, and phonophobia, it may present as a low frequency fluctuating sensorineural hearing loss. It is possible, however, to have a permanent hearing loss or vestibulopathy (as indicated by caloric weakness) secondary to a migraine attack. The commonality of these symptoms, often make it difficult to distinguish the disorders on clinical grounds alone.
This collection of symptoms may first be thought as consistent with Meniere’s disease, or other types of inner ear involvement, such as a recurrent vestibular neuronitis, particularly in patients with recurring episodes or attacks. The differential diagnosis of migraine and Meniere’s disease, then, may often present as a diagnostic enigma. In addition, 60% will report a lifelong history of motion sensitivity. Interestingly, the incidence of Meniere’s disease is twice as prevalent in migraineurs, as in the general population. The diagnostic challenge is further complicated if a differential diagnosis of multiple sclerosis (MS) is included. The initial onset of acute, debilitating vertigo will appear as the initial symptom in 5% of MS patients. As many as 50% of MS patients will experience at least one occurrence of acute vertigo at some time during the course of the disease. This may also be compounded by the fact that one in ten MS patients may present with hearing loss, which may be partial or complete, but often recovers, similar to the migraine or Meniere’s patient.
Mal de Debarquement
Mal de Debarquement, or disembarkment sickness, is actually a common and normal occurence1. It can best be defined as the continued sensation of motion, rocking, or swaying that persists after return to a stable environment following a prolonged exposure to motion, as one would encounter on a cruise, car, bus or train ride. It can be related to any form of conveyance. Most individuals who have enjoyed even a few hours on a fishing boat may have experienced this sensation of still being on the water, after they have returned to shore. This sensation may only last hours or even for a few days. It seems to be most noticeable when standing in the shower shampooing with eyes closed, lying in bed, or perhaps leaning against a stable fixture, as when one is at the sink washing the dishes. The Mal de Debarquement sensation that commonly occurs is independent of any seasickness or motion sickness that may be experienced during the cruise or travel. The individual may not have any ill feelings at all, and only notices the rocking sensation once on solid ground. A survey by Gordon, Sphitzer, and Donavitch, found that of 116 crewmembers of the Israeli naval force, 72% reported this common sensation with 67% reporting a very strong sensation following their initial voyage.
REFERENCES
- Sloane P.D. Dizziness in primary care: results from the National Ambulatory Medical Care Survey. J Fam Pract 1989; 29:33-38
- Kroenke kHz, Arrington MA, Mangelsdorff AD. The prevalence of symptoms in medical outpatients and the adequacy of therapy. Arch Intern Medical 1990; 150:1685-1689
- Baloh RW, Honrubia V. Clinical Neurophysiology of 3. the Vestibula