Causes of Dizziness

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Dizziness, vertigo, and disequilibrium seconds or days on end—are a primary are common symptoms reported by sign of a vestibular dysfunction, adults during visits to their doctors. especially when linked to changes in head They are all symptoms that can result position. By contrast, dizziness can be a from a peripheral vestibular disorder primary sign of a vestibular disorder in (a dysfunction of the balance organs addition to a broad array of of the inner ear) or central vestibular cardiovascular, neurological, metabolic, disorder (a dysfunction of one or more vision, and psychological problems. It is parts of the central nervous system that also quite possible that a person may help process balance and spatial infor- have a combination of problems, such as mation). Although these three symptoms a degenerative vestibular disorder along can be linked by a common cause, they with a visual deficit such as cataracts or a have different meanings, and describing neurological disorder such as a stroke. them accurately can mean the difference between a successful diagnosis and one Because of the many possible causes of that is missed. Dizziness is a sensation dizziness, getting a correct diagnosis can of lightheadedness, faintness, or unstead- be a long and frustrating experience. iness. Unlike dizziness, vertigo has a rotational, spinning component, and is Dizziness caused by the perception of movement, either of the vestibular disorders self or surrounding objects. The body maintains balance with sensory Disequilibrium simply means unstead- information from three systems: iness, imbalance, or loss of equilibrium  Vision that is often accompanied by spatial  Proprioception (touch sensors disorientation. in the feet, trunk, and spine)  Vestibular system (inner ear) Almost everyone experiences a few seconds of spatial disorientation at some Sensory input from these three systems point–for example, when a person is integrated and processed by the brain- watches a 3-D movie in the theater and stem. In response, feedback messages momentarily perceives an illusion of are sent to the eyes to help maintain moving or falling as the images rush steady vision and to the muscles to help past. However, frequent episodes of maintain posture and balance. vertigo—whether lasting only for a few

Definitions Specific vestibular system problems Vestibular dysfunction is most commonly Dizziness: a sensation of light- caused by head injury, aging, and viral in- headedness, faintness, or fection. Other illnesses, as well as genetic unsteadiness. Dizziness does not and environmental factors, may also cause involve a rotational component. or contribute to vestibular disorders. For Vertigo: the perception of more detailed information about specific movement vestibular system problems, please visit or whirling—either of the self or www.vestibular.org. Causes of dizziness surrounding objects. related to vestibular system dysfunction

Disequilibrium: unsteadiness, are listed below. imbalance, or loss of equilibrium; . An acoustic neuroma is a benign often accompanied by spatial tumor growing on the vestibulo- disorientation. cochlear nerve.

Spatial disorientation: a sensation . Autoimmune inner ear disease occurs of not knowing where one’s body when the defense capabilities of a mal- is in relation to the vertical and functioning immune system harm the A healthy vestibular system supplies the cells of the body that affect the ear. most reliable information about spatial Specific diagnoses include Cogan’s orientation. Mixed signals from vision or syndrome, Wegener’s granulomatosis, proprioception can usually be tolerated. systemic lupus, Sjogren’s syndrome, When sitting in a car at a railroad cross- and rheumatoid arthritis, among ing, seeing a passing train may cause the others. sensation of drifting or moving, and . Benign paroxysmal positional vertigo feeling a soft, thick carpet underfoot as (BPPV) is a condition resulting from opposed to a solid wood floor can produce loose debris (otoconia) that collects a floating sensation. However, within a part of the inner ear. In addi- compensating for vestibular system tion to head injury, BPPV can occur abnormalities is more problematic. Just due to the degeneration of inner-ear as a courtroom judge finds in favor hair cells during the natural process of between two sides presenting competing aging. evidence, the vestibular system serves as . Cervicogenic dizziness is a clinical the tie-breaker between conflicting forms syndrome of disequilibrium and of sensory information. When the ves- disorientation in patients with neck tibular system malfunctions, it can no problems that include cervical trauma, longer help resolve moments of sensory cervical arthritis, and others. conflict, resulting in symptoms such as dizziness, vertigo, and disequilibrium.

. Cholesteatoma is a skin growth that . Otitis media is a bacterial infection occurs in the middle ear behind the of the middle ear and meningitis is a eardrum. bacterial infection of the brain cover- ing that may spread to the inner ear. . An enlarged vestibular aqueduct houses the fluid-filled endolymphatic . Otosclerosis is an abnormal growth of duct, which is connected to the endo- bone of the middle ear that prevents lymphatic sac. The function of the structures within the middle and inner duct and the sac are affected when ear from working properly. the aqueduct is larger than normal. . Ototoxicity is caused by exposure to . Labyrinthitis and vestibular neuritis certain drugs or chemicals (e.g., intra- are inflammations caused by a viral venous aminoglycoside antibiotics) infection that can result in damage that damage the inner-ear nerve hair to hearing and vestibular function cells or the vestibulo-cochlear nerve. (labyrinthitis) or damage to vestibular . Perilymph fistula, caused by injury, is function only (vestibular neuritis). a tear or defect in the oval or round . Mal de débarquement is a sensation of window, which are small, thin rocking or movement that persists membranes that separate the middle after a cruise or other form of travel. ear from the fluid-filled inner ear.

. Ménière’s disease, or primary endo- . Superior canal dehiscence is an opening lymphatic hydrops, involves abnormal- in the bone overlying the uppermost ities in quantity, composition, or semicircular canal within the inner ear. pressure of the endolymph (one of the . Secondary endolymphatic hydrops fluids within the inner ear). It is a involves abnormalities in quantity, com- progressive condition. position, or pressure of the endolymph. . Middle ear pressure changes, such . Vascular compression of the vestibular as from colds or allergies, can result nerve is an irritation of the vestibular from swelling of the Eustachian tube portion of the vestibulo-cochlear nerve or the presence of fluid in the middle by a blood vessel. ear.

. Migraine associated vertigo (MAV) is Non-vestibular typically characterized by head pain causes of dizziness with symptoms associated Dizziness can be linked to a wide array with vestibular impairment such of problems and is particularly commonly as dizziness, motion intolerance, linked to blood-flow irregularities from spontaneous vertigo, sensitivity to cardiovascular problems. Non-vestibular light and sound, tinnitus, imbalance, causes of dizziness are listed below. and spatial disorientation. . An aneurysm is a weak spot in an

artery wall that balloons out and multiple systems. allows blood to leak into the vessel . People with severe degenerative walls. An aneurysm is a catastrophic arthritis of the spine can develop bone event that can cause severe dizziness spurs that may press on the vertebral and difficulty with walking. arteries and interfere with blood . An arrhythmia is a irregular or supply to the brain. abnormal heartbeat and can result in . Embolism can occur when an embolus, low blood flow to the brain, causing or blood clot, forms around a heart one to faint or feel faint. valve that is not working properly, or . Atherosclerosis is hardening or is released within the arteries to the narrowing of the vertebral arteries. brain, causing a stroke. The effects of In older people who have high blood a stroke may include temporary pressure, plaque is sometimes dizziness. However, if the embolus deposited within the arteries. This travels to the vestibular system, it narrows the interior of the arteries can cause severe dizziness. and impedes blood flow. Heredity may . A heart attack rarely causes dizziness; be a factor in development of this when it does, lack of blood to the condition. brain is the cause. . Carotid sinus reflex works rapidly . Hyperventilation is a condition in younger people but sometimes resulting from rapid breathing, when is much slower in older people, more carbon dioxide than normal is especially those with circulatory expelled. When this happens, the level problems. The carotid sinus is very of carbon dioxide in the blood falls and sensitive to decreases in blood affects the function of brain cells, pressure in the carotid artery. With causing temporary dizziness. a drop in blood pressure, the reflex constricts blood vessels in the lower . Certain medications, including some extremities and dilates vessels in the prescription and over-the-counter head to maintain a normal blood drugs, can cause temporary dizziness. pressure in the head and adequate . Nervous-system disorders such as blood flow to the brain. peripheral neuropathies (diminished . A defective heart valve usually nerve function in the legs or feet) involves the aortic valve, which and multiple sclerosis can cause when shut down (aortic stenosis) unsteadiness. prevents the proper amount of . Orthostatic hypotension is common blood from flowing to the brain. in older people, especially those with . Dehydration can produce light- circulatory problems and diabetes. headedness through its affect on When a person has low blood pressure

and pooling of blood in the lower part movements. Lightheadedness and of the body while sitting or laying unsteadiness can result. down, the process of standing up . A tumor may affect the brain stem, quickly can cause dizziness and the cerebellum (the coordination fainting. Normally, body reflexes center of the brain), or the part of accommodate such position changes. the cerebral cortex that controls However, when circulation problems voluntary muscle movements. impair these compensation mecha- nisms, faintness occurs. . Vasovagal syndrome is a nervous- system response that causes sudden . Osteoarthritis is a joint disease that loss of muscle tone in peripheral blood can narrow the openings in the neck vessels. vertebrae (bones) through which blood vessels flow. Blockage of these . Vision disturbances can occur when a vertebral arteries results in an person adjusts to bifocals or a new inadequate blood supply to the base eyeglass prescription, or must com- of the brain or brainstem—where the pensate for reduced vision due to balance information is controlled. This cataracts. causes symptoms of dizziness and Dizziness caused by lightheadedness. The condition is multiple sensory deficits termed vertebral basilar insufficiency. Maintaining balance and equilibrium can If this arterial narrowing takes place be very difficult when more than one gradually over time, other arteries neurologic problem exists. A mild may enlarge and take over some of vestibular disorder can be much more the function of the affected vessels. problematic when accompanied by a This event, called development of a visual deficit. The ability to compensate collateral blood supply, can’t happen if for a vestibular disorder is compounded the arterial narrowing occurs suddenly when there is also a deficit with proprio- (for example, if an embolus complete- ception due to disease or an injury and ly shuts off the blood supply). In such severe dizziness can result. Careful cases, death by stroke may result. evaluation, including a complete medical history noting all potential causes of . Stress, tension, or fatigue may cause dizziness, is essential to correct diagnosis the brain stem to function less effi- and treatment. ciently, resulting in some loss of automatic reflex control of balance. © 2012 Vestibular Disorders Association VEDA’s publications are protected under copyright. For This leads to elevated levels of activity more information, see our permissions guide at for the cerebral cortex as it works to www.vestibular.org. help maintain balance through the This document is not intended as a substitute for control of voluntary muscle professional health care

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