Equilibrium and Dizziness (Cohen) Flashcards
Dizziness
Definition: Altered sense of orientation in space
A nearly universal experience at some time
Prolonged or recurrent dizziness will bring most patients to the hospital or clinic
Correct diagnosis may be elusive at first, especially if patients give a vague description
Many words can be used: “spinning, off-balance, light-headed, feathery, woozy, can’t walk, sick, merry-go-round, high, cheap drunk,” etc
Helpful for the physician to separate symptoms into Vertigo vs. Light-headedness
Light-headedness
Numerous possible etiologies:
Most common the cause is cardiovascular: HYPOTENSION, or intermittent drops in blood pressure from taking anti-hypertensive medications
Arrhythmias, decreased cardiac output, valvular diseases
Medication adverse effects, especially cardiac and psychiatric or neurologic drugs
Autonomic diseases, including orthostatic hypotension
Polyneuropathy or spinal disorders, especially the cervical spine, which may also cause vertigo
Many times there is no known cause, including somatoform disorders and panic disorder, in some patients: “PSYCHOGENIC DIZZINESS”
Vertigo
More than just spinning: the patient’s misperception of his orientation to the environment
Usually there is some sense of the room spinning, or of his own body spinning
Also, any misperception of movement or motion
From a Latin word VERTERE “to turn”
Most common causes:
- “Peripheral”: Semicircular canals and utricle, saccule: benign paroxysmal positional vertigo, vestibular neuritis, Meniere’s Disease, trauma
- “Central”: Brainstem and cerebellar: stroke, hemorrhage, multiple sclerosis, tumors, alcohol, degenerative disorders, migraine
Benign Paroxysmal Positional Vertigo: BPPV, “Positional Vertigo”
Intermittent vertigo lasting less than a minute usually associated with changes in head position, especially looking up or down, “positioning vertigo”
Often first noticed when GETTING OUT OF BED IN AM
May cause nausea and vomiting if it is more than a few seconds in duration
Walking is often partly impaired, but most patients CAN walk across a room, even if they can’t walk a straight line
Sometimes a recent cold or upper respiratory infection can be recalled, but not always, or a recent trauma near one ear
Patients get full relief by being still, lying or sitting in a certain position can help
Typically lasts one to two weeks, rarely more than one month
BPPV Pathology
Thought to be due to detachment of the otolithic crystals of the maculae of the utricle or saccule detach and float into the posterior semicircular canal
The posterior semicircular canal is the lowest part of the labyrinth
Rapid head movements cause movement of these debris, activating the vestibular nerve, and giving the patient the sensation of vertigo
BPPV Diagnosis
Patients with BPPV may have had a recent illness or trauma
No loss of HEARING with the vertigo, unless there was some prior hearing loss, since patients with earlier damage to the ears may be more prone to BPPV
1. However, older patients with prior hearing loss, and younger patients with previous ear infections may be more prone to BPPV
Normal neurological examination except sometimes for prominent nystagmus, but patients are usually able to walk
In particular, no cerebellar findings
Vertigo may be brought-out by a quick head turn, or by the Dix-Hallpike Maneuver
Treatment of BPPV
The Epley Maneuver, similar to a prolonged Dix-Hallpike maneuver, can be an instant cure, but can also worsen the vertigo
Medications may also be helpful in suppressing the vestibular system:
1. Meclizine (Antivert) 12.5 mg or 25 mg three times a day for one to two weeks, may cause sedation
2. Scopolamine Patch; anti-cholinergic patch which is replaced every three days patients which BPPV for at least two weeks
3. Promethazine 25mg every eight hours; both anti-histaminic and anti-emetic effects, but also sedating
4. Diazepam (Valium) sometimes is helpful, too, but habit-forming
Meniere’s Disease
First described by Prosper Meniere in 1860s
Recurrent attacks over years and often decades, of vertigo, tinnitus and a decline in hearing and a sense of fullness or pressure in one ear
Ultimately patients have HEARING LOSS
Attacks are often minutes or hours long, and are separated by weeks or months with no vertigo at all between attacks
Very debilitating, sudden attacks which completely immobilize patients
There is a rare “Cochlear variant” of Meniere’s with prominent hearing loss but there is mild or no vertigo
Meniere’s Pathology
Increased volume of endolymphatic fluid, causing bulging throughout the inner ear
Sometimes called ENDOLYMPHATIC HYDROPS
Membranes holding endolymph may rupture during an attack, and spill the potassium-rich liquid into the perilymph, damaging both the vestibular nerve and the cochlear hair cells
Mostly a sporadic disease, but rarely runs in families
Meniere’s Treatment
During the attack, if lasting long enough, meclizine, promethazine, or scopolamine patches can be used
Attack frequency is often decreased by a low-salt diet and a potassium sparing diuretic
Surgical drainage/repair may be necessary, including a shunt to divert the endolymph A.destructive operations which destroyed the cochlea or cut the vestibular nerve are seldom done anymore by ear, nose and throat specialists
Fortunately, a majority of patients seem to lose their attacks eventually without surgery being necessary
Brain (Central) causes of dizziness
Vertigo arising from the brain, including the cerebellum, due to stroke, hemorrhage, tumors,
Occasionally from cervical spine disease
Post-traumatic, sometimes, especially trauma to the temporal lobes, brain stem, cerebellum
Migraine
1. One of the most common causes of intermittent vertigo in young adults and children; usually brief episodes with incapacitation, and they last for minutes rather than hours
Acoustic Schwannoma
A usually benign tumor of the vestibular portion of the eighth cranial nerve: also called Vestibular Neuroma or Vestibular Schwannoma, and >90% of tumors arise from the vestibular portion, and <10% on acoustic portion of nerve
Somewhat rare in incidence, and may not be diagnosed for years in some patients
Patients are more likely to complain of hearing loss at first, and later vertigo or headache and pressure in one ear
Usually a chronic sense of imbalance or vertigo rather than isolated, intermittent attacks of vertigo
ROARING TINNITUS becomes constant, sometimes with machine-like noises rather than simple ringing
Originates close to the brainstem in the internal auditory canal, and may compress the seventh and fifth cranial nerves, and ultimately the brainstem if large enough
Acoustic Schwannoma treatment
Surgery for almost all patients, even the elderly, if there are significant signs of disease
Gamma knife radiation can be used for smaller tumors, or in patients who are medically dangerous surgical candidates
Occasionally there may be meningiomas or more malignant tumors in this region, which cannot be completely removed, so patients need close follow-up
If bilateral, diagnostic of Neurofibromatosis II
Cerebellar Symptoms/Diseases
Complicated anatomy and multiple afferent and efferent connections
High density of neurons, possibly 40 – 50% of all neurons in the brain
Primary functions:
1. Coordination of movements
2. Regulation of muscular tone
3. Maintenance of posture and equilibrium
Primary cerebellar symptoms
Ataxia: Lack of coordination: from the Greek words
a taxis : lack of order or coordination
Causes inability to walk with full control of direction, and increased falls in nearly all patients
INTENTION TREMOR: actually a loss of direction or an ability to control antagonistic muscles of the shoulder and arm, as the target is being approached:
1. Not like other tremors, since the oscillations can be in multiple planes, and vary in frequency
2. Poorly named, but evident in all cerebellar diseases, especially chronic conditions such as tumor, multiple sclerosis, trauma or degeneration
