Vertigo or dizziness spells are more commonly due to an underlying disease rather than being a disease in itself.
Most common cause of vertigo
The commonest underlying cause of vertigo is due to disease of the balance mechanisms of the inner ear or due to diseases of the brain or central nervous system.
There are several specific causes, these include Labyrinthitis, Benign paroxysmal positional vertigo and so forth. (1-5)
This is due to infection of the inner ear that contains delicate tiny structures called the vestibular labyrinth.
The labyrinth is a maze that contains channels filled with a fluid. Movement of the head causes movement of this fluid leading to changes in sensation that are carried to the brain via a network of nerves or the vestibular nerves.
This labyrinth is useful for both hearing and maintaining the balance. It is aided by other organs such as the eyes.
Labyrinthitis leads to inflammation of this labyrinth. This causes differences in signals sent in from the labyrinth and those from eyes. This difference may cause vertigo or a feeling of movement even when the patient is still.
Labyrinthitis occurs due to viral infections like common cold or flu. Infection may also come from infected middle ears. There may be associated symptoms of ear pain and fever indicating the original site of infection elsewhere.
Benign paroxysmal positional vertigo (BPPV)
These attacks are usually short and recurrent and are more commonly seen in the elderly.
BPPV is the cause of vertigo in 20% of all cases. BPPV attacks occur commonly on sudden head movements, rolling in bed, look up or stand up suddenly or bend over rapidly.
There may be nausea and brief episodes of nystagmus. Nystagmus indicates rapid movement of the eyes usually side to side, on their own accord and uncontrollably.
BPPV is usually caused by dislodgement of small fragments in the labyrinth. It gives rise to altered balance sensation as the head moves and the fragments stimulate sensitive nerve endings.
When the head is still or moves slowly the fragments remain settled and do not stimulate the nerves and the sensation goes away. There is usually no tinnitus or hearing loss.
BPPV usually affects the elderly but may also occur in all ages especially after an episode of ear infection, ear surgery or head injury.
Other causes of vertigo
Other causes of vertigo include:
- Inflammation of the inner ear or vestibular neuritis. This leads to inflammation of the nerves of the inner ear leading to prolonged bouts of vertigo lasting over hours or days at a time. This can also be caused due to viral infections.
- Ménière's disease – This condition is characterized by three classical features of vertigo, hearing loss or fullness of ears and tinnitus or ringing of the ears.
- Vertigo may be caused after head injury. In these cases immediate attention in the emergency department is important.
- Migraine headaches may be associated with vertigo. There are other features like nausea and sensitivity to light (photophobia). Migraines are common causes of vertigo.
- Less common causes of vertigo include a stroke, multiple sclerosis or brain tumors especially those located in the lower part of the brain.
- Vertigo may be caused due to side effects of some medications. It may be seen after intake of some recreational drugs or alcohol.
Edited by April Cashin-Garbutt, BA Hons (Cantab)
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