Introduction
The vestibular system of the body maintains balance. It is divided into central and peripheral vestibular systems. The peripheral vestibular system is present in the inner ear (semicircular canals). It detects rotation, linear acceleration, and gravity. Vertigo is a feeling of head spinning. It is largely a peripheral vestibular system disorder.
The information from the inner ear is carried to the central vestibular system in the brain. On the other hand, presyncope occurs before syncope. It is a prior feeling to loss of consciousness. Vertigo and presyncope are easily confused as both cause dizziness. Hence, it is important to explain the difference.
What Are the Causes of Vertigo and Presyncope?
The cause of vertigo is vestibular pathology. On the other hand, presyncope occurs due to reduced blood flow to the brain. The causes of vertigo and presyncope are vast.
Peripheral Vertigo:
Benign Paroxysmal Positional Vertigo (BPPV):
It is the most common cause of peripheral vertigo. The semicircular canals have calcium crystals to apprehend movement. In BPPV, the crystals detach and float freely. The precipitating factors are age, head injury, or an infection. BPPV mostly affects middle-aged women. BPPV patients encounter vertigo with a change in head position, rolling over, or getting out of bed. The attacks often last for less than a minute. Also, there is a constant remission of the attacks.
Vestibular Neuronitis:
One of the most important functions of the eighth cranial nerve is balance and equilibrium. An infection of the vestibular nerve results in nerve inflammation and degeneration. Patients experience a sudden vertigo episode that can last up to many days.
Meniere’s Disease:
An increase in inner ear pressure leads to Meniere’s disease. The exact mechanism of Meniere’s disease is unknown. It results in improper nerve excitation with vertigo, hearing loss, and ringing sensation in the ears (tinnitus). Meniere’s disease is also termed endolymphatic hydrops.
Labyrinthitis:
A labyrinth is an inner ear structure. Labyrinthitis is inflammation of the labyrinth. An upper respiratory tract infection usually precedes it. Viral infection, bacterial invasion, bacterial toxins, and systemic disease are some causes of labyrinthitis. Vertigo is sudden and accompanied by hearing loss.
Trauma:
Head or cervical (neck) injury may lead to damage to the peripheral vestibular system. Hence, vertigo is the principal complaint in such conditions.
Central Vertigo:
Brain lesions or disorders comprise central vestibular system pathologies. A central pathology can also trigger vertigo. Associated symptoms such as hearing and vision loss depend upon the site of the lesion. It is reported that about 40 % of migraine patients have vertigo.
It may be accompanied by a headache. Ischemic stroke of the blood supply to the vestibular system, also called vertebrobasilar ischemic stroke (VIS), is another cause of central vertigo. Any major vessel obstruction can cause VIS. A transient ischemic attack (temporary stroke) is common in elderly individuals. It leads to vertebrobasilar insufficiency. In one-third of patients, vertigo is the only feature.
Presyncope:
Presyncope has cardiac and noncardiac causes. Cardiac causes are heart-related. They are more harmful. Arrhythmias can cause a critical decrease in cardiac output and blood flow to the brain. Noncardiac causes include vasovagal presyncope, orthostatic hypotension, medication-induced, vascular, and sepsis.
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Vasovagal Presyncope: It involves a sudden decrease in heart rate and blood pressure. It leads to nausea, flushing, light-headedness, and fainting.
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Orthostatic Hypotension: Low blood pressure after prolonged sitting or standing causes orthostatic hypotension, also called postural hypotension.
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Sepsis: It is an infection in the body. Untreated infection can lead to syncope.
What Is the Diagnosis of Vertigo and Presyncope?
Certain investigations can differentiate between vertigo and presyncope. A good history is important. There is no gold standard for diagnosing presyncope. However, initial tests such as electrolytes, complete blood count, cardiac enzymes, lactate, and blood cultures can be helpful. Imaging modalities such as computed tomography of the head (CT head) can be useful in head trauma patients.
Many causes of presyncope originate from the heart. Hence, echocardiography is of immense value in such patients. Presyncope patients are unlikely to undergo hospital admission. Common predictors that need further evaluation of an underlying condition include a heart or heart valve disease (arrhythmia, congestive heart failure), anemia, chest pain or palpitations, and abnormal vital signs.
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Dix-Hallpike Test: It is indicated for BPPV diagnosis. The patient is positioned horizontally on a table with a head-back position. The position is towards the affected ear. After five to twenty seconds, it will cause vertigo and nystagmus (involuntary rotatory eye movements). However, this test should be avoided in patients with neck pathology. Neck rotation and extension can be assessed before attempting the maneuver.
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Head Impulse Test: It can be used to differentiate between vertigo and presyncope. It is a bedside examination to check vertigo in vestibular neuritis patients. It involves quick head movements and neck rotation. If the test is positive, the eyes move off target with head-turning. It is followed by rapid corrective eye movements toward the target.
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Audiogram: An audiogram is an essential test to assess hearing thresholds in patients with hearing loss. An audiogram displays the type of hearing loss in a patient. It is also indicated when other causes, such as tinnitus, dizziness, noise exposure, and blast injury comprise a person’s hearing.
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Caloric Test: It is done to check the functional status of vestibular systems. It rules out central vertigo causes. One of the main advantages of the caloric test is that it does not require head movements. Hence, it results in better patient compliance. If the caloric test is negative, other causes of dizziness, such as presyncope, can be evaluated.
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Romberg’s Test: It evaluates central nervous system functioning. With eyes closed, feet together, and arms by the side, the patient has to hold the position. A failure to do so can depict central vertigo.
What Is the Treatment of Vertigo and Presyncope?
Presyncope treatment depends upon the cause. Fluid resuscitation is the foremost step in dehydrated patients. However, presyncope cannot be confirmed by standard diagnostic criteria. Syncope is an emergency and can be life-threatening. Vertigo is managed with physical exercises. It includes repositioning maneuvers and vestibular rehabilitation. Medications that include antihistamines prevent the histamine response that is responsible for vertigo. Benzodiazepines, selective serotonin uptake inhibitors (SSRIs), and anticholinergic agents are also helpful.
Conclusion:
Due to numerous causes of vertigo and presyncope, correct diagnosis becomes a challenge. The key to proper management is to properly differentiate vertigo from other causes of dizziness. It is because appropriate treatment can significantly improve the quality of life in such patients.
