Vertigo

Etiology

Vertigo is most often caused by a dysfunction in the vestibular system from a peripheral or central lesion.[1]

Peripheral etiologies include the more common causes of vertigo, such as benign paroxysmal positional vertigo (BPPV) and Ménière disease.[3] BPPV results from displaced calcium deposits or otoconia most commonly in the posterior semicircular canal and causes transient, paroxysmal and frequent episodes of vertigo lasting a few minutes or less, often associated with nausea and vomiting.[1] Unlike BPPV, patients with Ménière disease often experience tinnitus, hearing loss, and aural fullness in addition to vertigo. Endolymphatic hydrops is a distinct pathologic feature of Ménière disease.[4] [5] Symptoms of Ménière disease result from an increased endolymph volume in the semicircular canals. If left untreated, Meniere's disease can lead to progressive hearing loss. Two additional distinct causes of peripheral vertigo include acute labyrinthitis and vestibular neuritis. Both arise from inflammation, often caused by a preceding or concurrent viral infection.[1] Another viral-induced cause of vertigo is Herpes zoster oticus, also known as Ramsay Hunt syndrome.[6] In Ramsay Hunt syndrome, vertigo results from the reactivation of latent Varicella-zoster virus (VZV) in the geniculate ganglion, leading to inflammation of the facial nerve and vestibulocochlear nerve. This often leads to rashes, facial paralysis, tinnitus and hearing loss.[1]  Less common peripheral causes include cholesteatoma, otosclerosis, and a perilymphatic fistula. Cholesteatomas are cyst-like lesions filled with keratin debris that most often involve the middle ear and mastoid. [7] Otosclerosis is characterized by abnormal growth of bone in the middle ear, which leads to conductive hearing loss and may affect the cochlea, also causing tinnitus and vertigo.[8] A perilymphatic fistula is another less common cause of peripheral vertigo and often results from trauma.[1]

Central etiologies of vertigo should always be considered in the differential diagnosis especially in elderly patients. Ischemic or hemorrhagic strokes, particularly involving the cerebellum or brainstem, are life-threatening and must be ruled out by history, physical, and other diagnostic tests if warranted.[9][1] Other more serious central causes include tumors, particularly those arising from the cerebellopontine angle (See Image. Head MRI, T2 Cerebellopontine Angle (CPA) Tumor).[10] Examples of such tumors include a brainstem glioma, medulloblastoma, and vestibular schwannoma, which can lead to sensorineural hearing loss as well as vertiginous symptoms.[1] Vestibular migraines are a common central cause of vertigo, which are characterized by unilateral headaches associated with nausea, vomiting, photophobia, and phonophobia. Finally, multiple sclerosis has been associated with both central and peripheral causes of vertigo. Multiple sclerosis can cause vertigo by developing demyelinating plaques in the vestibular pathways.[11] BPPV is a common peripheral cause of vertigo in patients with multiple sclerosis.[1] Amongst the different diseases previously discussed, there are other causes that can lead to vertigo. These include medication-induced vertigo and psychologic disorders, including mood, anxiety, and somatization. Medications associated with vertigo include anticonvulsants such as phenytoin and salicylates.[1]

Epidemiology

Vertigo affects both men and women but is about 2 to 3 times more common in women than men.[1] It has been associated with various comorbid conditions, including depression and cardiovascular disease. Prevalence increases with age and varies depending on the underlying diagnosis. Based on a survey of the general population, the 1-year prevalence of vertigo is about 5% and an annual incidence of 1.4%. Dizziness, including vertigo, affects about 15% to over 20% of adults yearly.[12] For benign paroxysmal positional vertigo, the 1-year prevalence is about 1.6%, and it is less than 1% for vestibular migraine. The impact of vertigo should not be underestimated, as nearly 80% of survey respondents reported an interruption in activities of daily living, including employment and the need for additional medical attention. The prevalence of Menière disease has been recently reported to be 0.51%, which is much higher than previous reports.[13][12] 

Pathophysiology

Abnormalities in the vestibular system accounts for the symptoms of vertigo. Abnormalities may result from damage or dysfunction in the peripheral vestibular system, such as the vestibular labyrinth or vestibular nerve, or a disturbance central vestibular system found in the brainstem and cerebellum.[1] Though there may be a permanent vestibular disturbance, the symptom of vertigo is never permanent as the central nervous system adapts over days to weeks.[14] 

Tumors can cause vertigo by compression of the structures in the central vestibular system. Schwannoma is the most common lesion in the cerebellopontine angle.[15] Meningioma is the most common extra-axial tumor in adults and it is the second most common lesion in the cerebellopontine angle. Glomus jugulare and glomus jugulotympanicum are tumors of the chemoreceptor system and are the main primary tumors of the jugular foramen. Metastases should be a consideration in patients with known primary neoplasms or multiple brain lesions.

Infections can cause vertigo by involving the peripheral or central vestibular system. Viral labyrinthitis is the most common example. Otomastoiditis is an infection of the tympanic and mastoid cavities typically caused by bacterial agents, the most common being Streptococcus pneumoniae and Haemophilus influenzae. Acute cerebellitis is encephalitis that is restricted to the cerebellum. It is most common in children and Varicella-zoster virus is the leading cause. Cholesteatoma can be acquired or congenital, occurring in the pars flaccida or pars tensa, caused by the abnormal proliferation of keratinized stratified squamous epithelium.[16]

History and Physical

The initial goal in diagnosis is determining whether or not the patient is truly experiencing vertigo, as most patients report dizziness as a chief complaint. To elicit true vertigo symptoms, a provider may ask, "Does it feel like the room is spinning around you?" or "Do you feel like you are the one spinning?" [1] Once vertigo has been identified, a thorough history helps the provider differentiate between a central and peripheral etiology of vertigo. Eliciting a time course of symptoms is one of the best ways to determine the underlying etiology. A provider may classify whether the symptoms are acute or chronic, recurrent or persistent, and progressive or non-progressive. For instance, chronic and recurrent vertigo lasting for a few minutes or less is often associated with benign paroxysmal positional vertigo. A single episode lasting minutes to hours can be caused by a vestibular migraine or even a more serious underlying diagnosis, such as a transient ischemic attack. More prolonged episodes lasting days can be seen in both peripheral and central causes, such as vestibular neuritis or cerebellopontine angle tumors. [1]

Once a time course has been established, it is important to assess for associated symptoms as this can further help differentiate a central from a peripheral etiology. Nausea and vomiting are typical with acute episodes of vertigo and are not specific for any particular etiology. Since it is important to rule out central causes that may be progressive or life-threatening, such as a vertebrobasilar stroke or multiple sclerosis, providers must ask about any focal neurologic symptoms such as diplopia, dysarthria, dysphagia, and numbness or weakness.[17] An absence of focal neurologic symptoms does not completely rule out a serious central process, but its presence is red flag that warrants further investigation. Moving down the differential diagnosis of central causes of vertigo and associated symptoms, providers should inquire about symptoms of headache, photophobia, and visual auras as these often accompany vestibular migraines. There are other symptoms associated with vertigo that can stem from a peripheral lesion. For instance, patients may experience deafness and tinnitus concerning Ménière disease.[18] They may report a recent viral infection that can cause acute labyrinthitis and vestibular neuritis. Finally, it is important to review a patient's medication list and review social history for any history of substance or alcohol use. Medications that can affect vestibular function include anticonvulsants, salicylates, and antibiotics.[19]

When combined with a complete history, a focused physical examaination can help further differentiate a peripheral from a central cause of vertigo. Assessing for nystagmus is a key portion of the physical examination when a patient presents with vertiginous symptoms.[1] A functional vestibular system allows one to maintain gaze during rotation through vestibulo-ocular reflexes. With a unilateral dysfunction in the vestibular system, the eyes drift slowly away from a target and then correct with a fast movement in the reverse direction, resulting in the appearance of a “beat” in the direction of the fast phase. In a peripheral vestibular lesion, the fast phase is away from the affected side, and the frequency and amplitude of nystagmus increase with a gaze toward the side of the fast phase. For instance, a rightward gaze increases right-beating nystagmus. In peripheral lesions, the predominant direction of nystagmus remains the same regardless of the direction of gaze, while central lesions may present with nystagmus that reverses direction.[20] Central lesions can present with nystagmus in any direction, while peripheral lesions often present with horizontal nystagmus with a torsional component. It is important to note that nystagmus resulting from a peripheral lesion is never purely torsional or vertical. The head impulse or thrust technique is a physical examination technique to help further determine etiology. In this exam, patients are asked to fix their eyes on a distant target with prescription eyeglasses if needed. The head is turned quickly to the right or left by about 15 degrees. A normal response occurs when the eyes remain on the target. An abnormal response is when the eyes are dragged off the target in the direction of head turning, followed by a corrective saccade back to the target. This response implies a peripheral lesion resulting in a deficient vestibulo-ocular reflex on the side of the head turn. Finally, a provider may test for skew, which involves the examiner covering 1 eye and observing for a vertical or horizontal shift in the eye when uncovered. Central lesions sometimes produce a slight skew deviation. When the head impulse test is combined with an examination of nystagmus and a test for skew, this is referred to as the Head Impulse-Nystagmus-Test for Skew (HINTS) test.[21] A normal head impulse test on both sides with direction-changing nystagmus and/or skew deviation is concerning for a central lesion. An abnormal head impulse test with unidirectional nystagmus and absent skew deviation strongly suggests a peripheral lesion. The HINTS test may be more sensitive for the diagnosis of acute stroke than even MRI within the first 48 hours following symptom onset.[22]

Other physical examination techniques may be used to diagnose and treat vertigo, including the Dix-Hallpike maneuver.[23] It is the diagnostic test of choice when BPPV involving the posterior semicircular canals is suspected. Dix-Hallpike consists of two maneuvers. A patient sits on an exam table facing forward with eyes open, and the provider turns the patient's head 45 degrees to the right. The provider supports the patient's head while the patient lies back quickly to a supine position, with the head hanging about 20 degrees off the end of the table. The patient remains in this position for 30 seconds before returning to the upright position, where they are observed for another 30 seconds. This maneuver is repeated with the head turned to the left. The test is positive if, at any point, the maneuvers produce vertigo with or without nystagmus.[1] Another helpful diagnostic maneuver for peripheral vertigo is the Unterberger test. It consists of two maneuvers. A patient stands in an upright position with eyes closed. The provider then instructs the patient to walk in place for 60 seconds. The test is positive if there is rotation of the body to one side while walking in place. [24] Furthermore, gait and balance testing can also aid in localization. Patients with unilateral peripheral disorders often lean or fall toward the side of the lesion; whereas, patients with cerebellar lesions are often unable to walk without assistance, and the direction of falling with Romberg testing is variable. Many primary care and specialist physicians neglect the basics of history and physical examination, leading to unnecessary imaging and medications.[25]

The otoscopic exam should be completed to rule out an obvious infection such as acute otitis media, and bedside tests of hearing can be useful in differentiating other causes of vertigo. Weber and Rinne tests are performed at the bedside to screen for conductive and sensorineural hearing loss.[26] However, audiometry is more sensitive than bedside testing in detecting hearing loss. A unilateral hearing loss points strongly to a peripheral etiology, but further diagnostic imaging with MRI is warranted if a cause can not be identified. There is insufficient high-quality evidence for the diagnostic value of the absence of hearing loss, as assessed by pure tone audiometry, to predict BPPV in patients with vertigo.[27]

Evaluation

The acronym STANDING describes a 4-step algorithm based on nystagmus observation and well-known diagnostic maneuvers. It includes the discrimination between SponTAneous and positional or gaze-evoked nystagmus, evaluation of the Nystagmus Direction (whether it is unidrectional or direction-changing), the head Impulse test, and the evaluation of equilibrium (staNdinG).[28] Laboratory testing is often not useful in identifying the etiology of vertigo. Diagnostic testing with brain imaging is indicated if a central lesion is suspected. Clinicians may find it difficult to distinguish between a central lesion, such as infarction, and a peripheral lesion, such as vestibular neuritis, where the symptoms of vertigo can last for days. In this case, neuroimaging is recommended in patients with risk factors for stroke, associated focal neurologic deficits, a new headache, and when the physical examination is not entirely consistent with a peripheral lesion. The modality of choice is brain MRI and MR angiography, as CT scans are less sensitive than MRI for diagnosing and evaluating central lesions due to poor resolution in evaluation of posterior fossa structures. However, if brain MRI is unavailable or contraindicated, a CT scan with thin cuts may be used, particularly through the brainstem and cerebellum.[16]

Treatment / Management

Treatment of vertigo depends on the etiology, and treating the underlying etiology often improves the symptoms of vertigo. Medications may be useful to suppress vestibular symptoms in acute episodes that may last a few hours to days. The most common medications used for symptomatic relief include antihistamines, calcium channel blockers, benzodiazepines, and antiemetics. The most commonly used antihistamines are meclizine and betahistine.[29] Calcium channel blockers include cinnarizine. Given their sedative effects, caution is advised in using antihistamines, benzodiazepines, and antiemetics in elderly patients.(A1)

Additional non-pharmacologic treatments for patients with permanent unilateral or bilateral vestibular dysfunction include physical therapy with vestibular rehabilitation.[30] Vestibular rehabilitation exercises train the brain to maintain balance through alternative visual and proprioceptive clues. Several randomized control trials have shown benefits in vestibular rehabilitation, including a decrease in vertiginous symptoms, a decrease in position and movement-provoked dizziness, and an improvement in activities of daily living.[31][32][33](A1)

In some patients, particularly those diagnosed with vestibular neuritis, a combination of pharmacologic and nonpharmacologic therapy is recommended. In vestibular neuritis, corticosteroids are recommended in the acute setting in addition to vestibular rehabilitation. In patients with Ménière disease, lifestyle adjustments in addition to medication and vestibular rehabilitation have shown to be effective.[34] Patients with Ménière disease may be particularly sensitive to a high salt diet, caffeine, and alcohol. Avoiding known triggers can help to alleviate symptoms. Diuretics may also be prescribed when diet modification alone is not sufficient in controlling symptoms. Acute episodes can be symptomatically treated with vestibular suppressants like meclizine.

Patients with benign paroxysmal positional vertigo benefit from non-pharmacologic agents. The primary treatment for BPPV is focused on head rotation maneuvers that displace calcium deposits back to the vestibule through canalith repositioning or the Epley maneuver.[35] The benefit of the Epley maneuver is that the patient can perform it at home. To perform a modified Epley maneuver (as shown in the image), instruct the patient to position themselves upright on a bed with their head turned 45 degrees to the left and a pillow behind them. The pillow should be positioned so that it is directly under their shoulders when supine. Once the patient is in position, they should quickly back onto the pillow so the head is reclined onto the bed. They should hold this position for 30 seconds. Without raising their head, they should turn their head 90 degrees to the opposite side (right) and hold this position for another 30 seconds. After 30 seconds, they should turn their body and head another 90 degrees to the right and wait another 30 seconds. Finally, they should sit up on the right side of the bed. This maneuver can be repeated starting on the opposite side and should be performed at least 3 times a day until the patient has no further episodes of positional vertigo for 24 hours. The Epley maneuver is effective in 50 to 90% of patients.[36] Unfortunately, BPPV is intractable in a select number of patients, and surgical treatment can be an option, particularly if symptoms are disabling. Surgical options include occlusion of the posterior canal with bony plugs or transection of the posterior ampullary nerve. Either surgical procedure has risks of hearing loss. (See Image. Epley Maneuver.)(A1)

Differential Diagnosis

The differential diagnosis of vertigo is extensive as it can arise from a central or peripheral lesion in the vestibular system. Therefore, it is important to differentiate vertigo from symptoms of disequilibrium, pre-syncope and lightheadedness. An extensive list of vascular, infection, traumatic, inflammatory, demyelinating, metabolic, iatrogenic and neoplastic causes can lead to these symptoms. [37]

Prognosis

Prognosis depends on the etiology of vertigo. Generally, peripheral causes have a better prognosis while central causes have a worse prognosis. Benign paroxysmal positional vertigo recurrence rates are 50% at 5 years. There is the persistence of dizziness related to anxiety in almost a third of patients 1 year after vestibular neuritis.[13] According to Perrez-Garrigues et al, the number of episodes of vertigo is higher in the first years of the disease and decreases in later years regardless of whether patients receive treatment; most patients reach a "steady-state phase free of vertigo."[38] As with vertigo, hearing loss is highest in the early years of the disease and stabilizes in later years. Usually, there is little to no recovery from hearing loss.[39] The acute vertigo from labyrinthitis should resolve within days; however, milder symptoms may persist for several weeks. The prognosis is usually good if the patient has no serious neurological sequelae. However, patients with neurological complications from central causes may require further interventions. [40]

Complications

The key to arriving at the diagnosis is to differentiate vertigo from other causes of dizziness or imbalance and to distinguish central from peripheral causes of vertigo. An accurate diagnosis is essential and critical in life-threatening causes. Peripheral causes of vertigo are usually associated with little to no complications. Complications arising from the central causes of vertigo are variable, depending on whether the etiology is accurately identified and properly managed. [41]