BPPV – Benign Paroxysmal Positional Vertigo is the commonest cause of Acute Peripheral Vertigo (giddiness, ‘chakkar’).
It is generally considered that this is one disease but this is not true.
There are many variants of BPPV and as we understand more about this disease we realize that many different parts of the inner ear may be involved.
BPPV is caused by the accumulation of particles (Otoliths) in the Semicircular canals – these are calcium crystals that get deposited in the vestibular balance organs and their movement caused by neck movement leads to giddiness. The Otoliths sometimes arise in the Cupula as well.
The giddiness associated with BPPV is sudden and very short-lasting – a few seconds – but this may be followed by some unsteadiness for some time. There may be associated with nausea and vomiting.
It is usually seen in older individuals and sometimes there may be a previous history of head trauma.
Though the giddiness has no relationship with cervical spondylosis, the association with neck movement sometimes leads patients and clinicians to feel that the episode is because of Cervical Spondylosis. That is not true.
To understand the different variants of BPPV, we need to look at the anatomy of the Inner Ear.
The Inner Ear – courtesy Slideshare.net
The Inner Ear performs the two most important functions in the human body- Hearing and Balance.
The part of the inner ear that is responsible for hearing is the Cochlea and the part responsible for balance is the Vestibule.
The vestibular system consists of the vestibule and the semicircular canals, and the structures of the membranous labyrinth inside.
The constituents of the Vestibular system then are the Utricle, the Saccule, and the three semicircular canals. The semicircular canals are oriented in different directions and are responsible for maintaining balance in their respective axes.
Types of BPPV
The most useful BPPV classification for clinical practice is based on which canal is involved.
• Posterior semicircular canal (PSC)
• Lateral semicircular canal (LSC)
• Anterior semicircular canal (ASC)
• Multicanalar BPPV
– Simultaneous involvement: Posttraumatic BPPV
– No simultaneous involvement: Canalar conversion
The implication of this that no single test or manoeuvre is sufficient to diagnose or treat the disease.
BPPV arising from the Posterior Semicircular Canal is the most common lesion, accounting for nearly 80 % of the cases.
To understand which canal could be causing the giddiness in the patient a series of tests are carried out to come to a diagnosis.
Once we know that an appropriate manoeuvre is done to correct the condition.