Benign Paroxysmal Positional Vertigo (BPPV)
Benign paroxysmal positional vertigo is the most frequent cause of vertiginous symptoms. Occurrences may vary from a few seconds to a few minutes and are strictly dependent on the position of the head. As a matter of fact, depending on such position, the onset of a dizzying crisis is triggered, which can be characterised as intense, if not violent, short and paroxysmal.
BPPV is due to the detachment of the otoliths that move into the semicircular canals (posterior, lateral or anterior / superior) of the labyrinth. BPPV therefore varies according to the canal concerned, which in turn is stimulated by the position taken by the head, i.e., tipping backwards or sideways. Dizziness events can also be described or defined as repetitive in the active phase. The inactive phase is characterized by silent intervals of variable duration followed by the recurrence of the condition.
The ratio between females and males shows a prevalence in the former in a variable ratio, but often referred to as 2: 1. The age in which there is a peak of incidence is that between 50 and 60 years, although it is not absent in other age groups. However, it is much rarer in the age groups that include childhood to adolescence.
There can be a variety of causes for BPPV, such as vascular, viral, post-traumatic, post otologic surgery. However, more frequently the causes are idiopathic. According to recent studies, vitamin D3 deficiency seems to be of some relevance.
Regarding BPPV, it is necessary to distinguish two cases, the theory of cupulolithiasis and the theory of canalolithiasis.
- THEORY OF CUPULOLITHIASIS
Migration of otoconial debris of the utricular macula to the cupula of the semicircular canal, which undergoes gravitational alterations from the adhesion of such debris onto it. (Schucknecht-1969)
- THEORY OF CANALOLITHIASIS
Migration of otoconial debris or high-density particles (for example white blood cells or clots) that enter and disperse in the semicircular canal, moving freely along the entire canal until settling in its most declining position by following the movements of the head
The posterior semicircular canal seems to be the most often affected, while the least frequent is the anterior semicircular canal, all of which can be explained by the mere position of the canals in accordance with their gravitational positioning. In fact, the anterior semicircular canal is in a more cranial position with respect to the labyrinth. This makes the possibility for otoliths to enter it less likely, and given the position, their spontaneous exit more likely.