Benign Paroxysmal Positional Vertigo – A Neglected Cause of Dizziness

Vertigo is a symptom which is described as an overwhelming sensation that everything, including yourself, is in motion. This feeling can induce bouts of dizziness, disruption of balance and nausea (Palmeri & Kumar, 2018). Vertigo can be classified as peripheral and central. Peripheral vertigo is caused by issues of balance control centres located in the inner ear while central vertigo is related to problems afflicting the brain. Encountering vertigo is an extreme cause of concern for an individual as it can be the consequence of a brain tumour, a stroke or inflammation of the nerve innervating the brain from the inner ear (National Health Service Scotland, 2023). Yet, it is not always necessary to become alarmed immediately upon experiencing vertigo as it can be a case of Benign Paroxysmal Positional Vertigo (BPPV). Although it remains largely undiagnosed, BPPV is one of the most common examples of peripheral vertigo which is almost always successfully treated (You et al., 2018). This article will describe the mechanisms involved in instigating BPPV, mention the symptoms and outline the first-line treatment of BPPV.

Anatomy of the Inner Ear

To understand the mechanism behind BPPV, it is important to have an awareness of the anatomy of the inner ear. The inner ear consists of an auditory structure, known as the cochlea, and a vestibular system made up of the vestibule, three semi-circular canals along with their ampullae, the utricle and the saccule. The inner ear is a bony structure but it also has a membranous labyrinth deep within that carries a fluid called the endolymph (Ekdale, 2015). The flow of the endolymph inside inner ear structures allows for the transduction of external information (such as a sound or change in head position) into nerve impulses which are interpreted by the brain (Highstein & Holstein, 2012). Head movements are perceived by the brain through the help of semi-circular canals. The semi-circular canals are positioned almost exactly perpendicularly to each other which causes each structure to register information about a specific plane of motion. The superior semi-circular canal interprets vertical head rotations, such as when someone nods their head. The lateral semi-circular canal can register information regarding horizontal head movement, for example when someone shakes their head for ‘no’. Finally, the posterior semi-circular canal is needed to understand the motion when one tilts their head towards their shoulder (Purves et al., 2001). The sensing of position is achieved when the endolymph inside the semi-circular canals is displaced by the head movement after a period of lagging behind (caused by inertia). The fluid produces a force onto the sensory hair cells located in the ampullae of the semi-circular canals, bending the stereocilia on the hair cell and inducing an excitatory or inhibitory impulse that travels along a nerve to the brain (Highstein & Holstein, 2012).

Figure 1: Signal transduction in the vestibular system of the inner ear (Psy 3031 & Spring 2020, n.d.)

The utricle and saccule are structures of the inner ear known as the otolith organs. Unlike in the ampullae where sensory signals were produced by the flow of the endolymph, small crystals composed of calcium carbonate and proteins create the force needed to activate hair cells in the otolith organs (Purves et al., 2014). The crystals are called otoliths or otoconia. These crystals form a layer above the sensory membrane of the otolith organs (Lundberg et al., 2015), which consists of hair cells immersed in a gel-like substance, and have a stimulatory effect by changing in which direction the cilia of the hair cells bend towards. The utricle is sensitive to horizontal acceleration, such as that experienced when sitting in an accelerating car, while the saccule senses the change in displacement which occurs vertically, for example when a person is riding in an elevator (Casale et al., 2022).

Why does BPPV occur?

There are two proposed mechanisms by which BPPV manifests. In both mechanisms, the primary abnormality is the dislodgement of the otoliths from their typical position within the otolith organs. The otolith crystals enter the semi-circular canals of the inner ear and either remain free-flowing in the endolymph or anchor themselves to a structure known as the cupula in the ampullae of the semi-circular canals. The otoliths can activate hair cells in the inner ear structures even when the head is no longer in motion (Palmeri & Kumar, 2018). Consequently, the presence of otoliths within the semi-circular canal of one ear causes a false sensation of movement which cannot be compensated by the other ear, resulting in vertigo. The most common form of BPPV is when the otoliths enter the posterior semi-circular canal of the inner ear (Campbell et al., 2019).

Figure 2: The inner ear in patients with BPPV (Cleveland clinic, n.d)

What Are the Signs of BPPV?

In most cases, BPPV is idiopathic, meaning there is no clear cause that could have resulted in the dislodgement of the otoliths. However, infections of the inner ear labyrinth, as well as trauma, have been observed as more direct causes of BPPV (Yetiser, 2019). As vertigo on-set can be a frightening and a concerning experience for an individual, the more severe causes of vertigo are usually clinically tested for (Bojana Bukurov et al., 2023). Due to this, BPPV is found to be misdiagnosed in around 60% of patients and has a cost-ineffective diagnostic procedure due to the utilisation of incorrect diagnostic tests, such as magnetic resonance imaging and computed tomography (Qian et al., 2017). In reality, BPPV has a relatively easy diagnostic criteria; a person needs to experience recurring episodes of vertigo, especially after movements like rolling over in bed or raising their head up from a lying down position, and have a positive reaction to the Dix-Hallpike manoeuvre. The Dix-Hallpike manoeuvre involves transferring a seated patient, whose head is rotated to one side, into a lying down position where their head falls back. The doctor then observes the patient for rapid, uncontrolled eye movements (known as nystagmus) which are indicative that the patient’s brain is perceiving loss of equilibrium and vertigo. The manoeuvre is done on both sides to determine in which ear the otoliths have dislodged (You et al., 2018). Patient history can help a doctor diagnose a patient with BPPV as in this condition, the episodes of vertigo are relatively short (usually less than 20 seconds) and can appear suddenly and repetitively, instead of the slow on-set seen in central vertigo (Cranfield et al., 2010).

BPPV can occur at any age but is predominantly seen in individuals over the age of 50 because of the suspected role of ageing in the cause of otolith organ degeneration (von Brevern et al., 2007). BPPV occurrence is disproportionately higher in women than in men. Despite there being no clear difference in the inner ear structure between men and women, researchers propose that low levels of the sex hormone oestrogen cause disrupted metabolism of otoliths and increase their chance of detachment from the otolith organs (Jeong, 2020). Additionally, low vitamin D in the serum has been linked with repeated BPPV. This may be due to the impaired bio-mineralisation of otoliths as a result of decreased calcium absorption caused by a deficiency of vitamin D (Abdelmaksoud et al., 2021).

Figure 3: The Dix-Hallpike manoeuvre (Cleaveland clinic, n.d)

Treatments of BPPV

The symptomatology as well as the pathophysiology of BPPV may leave a false impression that the condition is hard to treat. Yet, the first-line treatment, known as the canalith repositioning procedure, is a simple technique that can be performed by the doctor or at home by the patient (Munoz et al., 2007). It is reported that the procedure resolves BPPV in approximately 90% of cases immediately after it is done, with the success rate going up to around 100% when it is repeated a week later (Gaur et al., 2015). There are two main manoeuvres that are used, depending on which semi-circular canal of the inner ear is affected; the Epley manoeuvre is used for the treatment of posterior semi-circular canal BPPV (Cranfield et al., 2010) and the Barbecue roll manoeuvre is performed to treat lateral semi-circular canal BPPV (Escher et al., 2007). The main purpose of these procedures is to hold a patient’s head in different positions in a specific order so that the dislodged otoliths can be repositioned back into the utricle or saccule. Canalith repositioning techniques are typically done by medical professionals (Munoz et al., 2007). This is because it is suggested that the procedure is less effective if done at home due to errors made by the patients in orientating their heads at the right angles. However, researchers propose that patients can be taught to perform the manoeuvres themselves with the assistance of an inertial measurement unit sensor-based guiding system that provides auditory instructions during the procedure. Auditory cues from the guiding system, such as “turn your head a little bit more to the right” and “stay in this position for one minute”, were shown to improve the accuracy of the angle at which patients positioned their heads for both the Epley and the Barbecue roll manoeuvre (Pastor et al., 2023). For more severe cases of BPPV, when dizziness causes nausea and vomiting, medications such as cyclizine and betahistine can be used (Hui et al., 2022).

Figure 4: Two canalith repositioning manoeuvres: Epley and Barbecue roll manoeuvre (Pastor et al., 2023)

Conclusion

BPPV is an example of peripheral vertigo that can present itself in patients as short episodes of severe vertigo after certain head movements. Although experiencing such an episode may greatly alarm a patient, this article has hopefully shown that BPPV has a straightforward diagnosis criteria and treatment plan. More research is needed to explore the exact mechanisms behind why otoliths have the tendency to dislodge, especially focusing on why certain populations are affected more than others. Education about BPPV, in patients and healthcare professionals, is also a step that needs to be taken to improve BPPV diagnosis and treatment.

Bibliographical References

Abdelmaksoud, A. A., Fahim, D. F. M., Bazeed, S. E. S., Alemam, M. F., & Aref, Z. F. (2021). Relation between vitamin D deficiency and benign paroxysmal positional vertigo. Scientific Reports, 11(1). https://doi.org/10.1038/s41598-021-96445-x

‌

Bojana Bukurov, Dragana Nenezic, Pot, D., Nemanja Radivojevic, Tjasa Ivosevic, & Jotic, A. (2023). Adoption of clinical practice guidelines in cases of benign paroxysmal positional vertigo. https://doi.org/10.1007/s00405-023-07981-3

‌

Campbell, B., Kimura, K., Yawn, R., & Bennett, M. (2019). Pathophysiology and Diagnosis of BPPV. Diagnosis and Treatment of Vestibular Disorders, 141–150. https://doi.org/10.1007/978-3-319-97858-1_11

‌

Casale, J., Browne, T., Murray, I., & Gupta, G. (2022). Physiology, Vestibular System. PubMed; StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK532978/#:~:text=The%20vestibular%20system%20functions%20to

‌Cranfield, S., Mackenzie, I., & Gabbay, M. (2010). Can GPs diagnose benign paroxysmal positional vertigo and does the Epley manoeuvre work in primary care? British Journal of General Practice, 60(578), 698–699. https://doi.org/10.3399/bjgp10x515557

‌

Ekdale, E. G. (2015). Form and function of the mammalian inner ear. Journal of Anatomy, 228(2), 324–337. https://doi.org/10.1111/joa.12308

Gaur, S., Awasthi, S. K., Bhadouriya, S. K. S., Saxena, R., Pathak, V. K., & Bisht, M. (2015). Efficacy of Epley’s Maneuver in Treating BPPV Patients: A Prospective Observational Study. International Journal of Otolaryngology, 2015, 1–5. https://doi.org/10.1155/2015/487160

‌

‌Highstein, S. M., & Holstein, G. R. (2012). The Anatomical and Physiological Framework for Vestibular Prostheses. The Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology, 295(11), 2000–2009. https://doi.org/10.1002/ar.22582

Hui, J., Lei, Q., Ji, Z., & Zi, D. (2022). Betahistine alleviates benign paroxysmal positional vertigo (BPPV) through inducing production of multiple CTRP family members and activating the ERK1/2-AKT/PPARy pathway. 55(1). https://doi.org/10.1186/s40659-022-00385-3

‌

‌Jeong, S.-H. (2020). Benign Paroxysmal Positional Vertigo Risk Factors Unique to Perimenopausal Women. Frontiers in Neurology, 11. https://doi.org/10.3389/fneur.2020.589605

‌

Lundberg, Y. W., Xu, Y., Thiessen, K. D., & Kramer, K. L. (2015). Mechanisms of Otoconia and Otolith Development. Developmental Dynamics : An Official Publication of the American Association of Anatomists, 244(3), 239–253. https://doi.org/10.1002/dvdy.24195

‌

Munoz, J. E., Miklea, J. T., Howard, M., Springate, R., & Kaczorowski, J. (2007). Canalith repositioning maneuver for benign paroxysmal positional vertigo. Canadian Family Physician, 53(6), 1048–1053. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1949221/

‌

National Health Service Scotland. (2023). Vertigo. https://www.nhsinform.scot/illnesses-and-conditions/ears-nose-and-throat/vertigo#causes-of-vertigo

Palmeri, R., & Kumar, A. (2018, December 2). Benign Paroxysmal Positional Vertigo (BPPV). Nih.gov; StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK470308/

Pastor, C. A. C., Kwon, C., Joo, J. S., Kim, H. C., Shim, D. B., Ku, Y., & Suh, M.-W. (2023). Feasibility of an inertial measurement unit sensor-based guiding system for benign paroxysmal positional vertigo treatment: A pilot study. Scientific Reports, 13(1), 3169. https://doi.org/10.1038/s41598-023-29685-8

‌

Purves, D., Augustine, G. J., Fitzpatrick, D., Katz, L. C., Anthony-Samuel LaMantia, McNamara, J. O., & S Mark Williams. (2014). The Otolith Organs: The Utricle and Sacculus. Nih.gov; Sinauer Associates. https://www.ncbi.nlm.nih.gov/books/NBK10792/

‌

Purves, D., Augustine, G. J., Fitzpatrick, D., Katz, L. C., LaMantia, A.-S., McNamara, J. O., & Williams, S. M. (2001). The Semicircular Canals. Neuroscience. 2nd Edition. https://www.ncbi.nlm.nih.gov/books/NBK10863/#:~:text=Whereas%20the%20otolith%20organs%20are

‌Qian, S. X., Li, F., Zhuang, J. H., Chen, Y., Yang, H. L., Zhou, X. W., Gu, H. H., & Gao, B. (2017). [Misdiagnosis and associated costs of benign paroxysmal positional vertigo]. Zhonghua Yi Xue Za Zhi, 97(14), 1057–1060. https://doi.org/10.3760/cma.j.issn.0376-2491.2017.14.006

‌von Brevern, M., Radtke, A., Lezius, F., Feldmann, M., Ziese, T., Lempert, T., & Neuhauser, H. (2007). Epidemiology of benign paroxysmal positional vertigo: a population based study. Journal of Neurology, Neurosurgery, and Psychiatry, 78(7), 710–715. https://doi.org/10.1136/jnnp.2006.100420

‌

Yetiser, S. (2019). Review of the pathology underlying benign paroxysmal positional vertigo. Journal of International Medical Research, 030006051989237. https://doi.org/10.1177/0300060519892370

‌

You, P., Instrum, R., & Parnes, L. (2018). Benign paroxysmal positional vertigo. Laryngoscope Investigative Otolaryngology, 4(1). https://doi.org/10.1002/lio2.230

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