What is vertigo?

In medical terms, vertigo is a specific kind of dizziness – a sense that you, or your environment, is moving or spinning, even though there is no movement.

In the medical sense, vertigo does not mean a fear of heights. Instead, acrophobia is the diagnostic term used to refer to a fear of heights that is excessive and inappropriate to a situation. With acrophobia, a person overestimates danger, becomes distressed and avoids heights altogether.

Vertigo, then, is a specific symptom unrelated to heights that have various medical causes.

Vertigo is thereby set apart from presyncope, which is a sense of almost fainting (typically a result of temporarily lowered blood pressure). Disequilibrium is also something separate, seen in older people – an unsteadiness due to poor balance and strength.Light-headedness, often associated with anxiety, is different too, sometimes called psychogenic vertigo.

What causes vertigo?

The rotational dizziness that defines vertigo is brought on by one of two causes – disturbance in either:

  • The balance organs of the inner ear, or
  • Parts of the brain or sensory nerve pathways.

Peripheral Vertigo

Vertigo is a special kind of dizziness that feels like spinning.

Peripheral vertigo is a term that collects together the inner ear causes.

The labyrinth of the inner ear has tiny organs that enable messages to be sent to the brain in response to gravity. By telling our brains when there is movement from the vertical position, we are able to keep our balance, to maintain equilibrium.

Disturbance to this system, therefore, produces vertigo and can be created by inflammation among other causes. Viral infection is the inflammation seen in the following two conditions:

  • Labyrinthitis – this is inflammation of the inner ear labyrinth and vestibular nerve (the nerve responsible for encoding the body’s motion and position)
  • Vestibular Neuronitis – this is thought to be due to inflammation of the vestibular nerve.

Ménière’s disease can also be caused by inflammation, but this can be due to bacterial as well as viral infection.This form of vertigo is thought to be caused by the high pressure of a fluid in a compartment of the inner ear (a swelling that is also known as endolymphatic hydrops).

As well as infection, Ménière’s disease can result from metabolic and immune disorders.
Benign paroxysmal positional vertigo (BPPV) is thought to be caused by a disturbance in the otolith particles.

These are the crystals of calcium carbonate within inner ear fluid that pull on sensory hair cells during movement and so stimulate the vestibular nerve to send positional information to the brain.

In people with BPPV, normal movement of the endolymph fluid continues after head movement has stopped.

Benign paroxysmal positional vertigo is twice as common in women than men, usually, affects older people and most often arises without a known cause (idiopathic). While most cases are spontaneous, BPPV vertigo can also follow:

  • A head injury
  • Reduced blood flow in a certain area of the brain (vertebrobasilar ischemia)An episode of labyrinthitis
  • Ear surgery
  • Prolonged bed rest.

Beyond peripheral vertigo brought on by benign paroxysmal positional vertigo, labyrinthitis, vestibular neuronitis or Ménière’s disease, inner ear disturbance can also be caused by drug toxicity and syphilis.

Rare causes are: perilymphatic fistula (tear in one or both of the membranes separating the middle and inner ear), cholesteatoma erosion (skin growth behind the eardrum), Herpes zoster oticus (a viral infection of the ear, also known as Ramsay Hunt syndrome), otosclerosis (a genetic ear bone problem that causes deafness).

Central Vertigo

Central vertigo is a term that collects together the central nervous system causes – involving a disturbance to one of the following two areas:

  • The parts of the brain (brainstem and cerebellum) that deal with interaction between the senses of vision and balance, or
  • Sensory messages to and from the thalamus (part of the brain).

A migraine headache is the most common cause of central vertigo. An estimated 40% of patients with a migraine have some accompanying vertigo (involving disrupted balance and/or dizziness) at one time or another.

Uncommon causes are stroke and transient ischemic attack, cerebellar brain tumor, acoustic neuroma (a noncancerous growth on the acoustic nerve in the brain) and multiple sclerosis.