People mean many different things when they say that they are dizzy. Vertigo is the dizzy sensation associated with spinning around in a circle too fast, or as if the world is spinning around you. Vertigo can be very uncomfortable, and may sometimes lead to nausea or vomiting. It can be hard to get out of bed, much less walk around and do the tasks that we need to accomplish every day.
While most causes of vertigo aren't life-threatening, some are very serious, like a stroke in the back of the brain near the cerebellum. On the other hand, many kinds of vertigo can be easily treated with simple maneuvers like head positioning.
So how are we supposed to recognize the cause of sudden (acute) vertigo? To understand the cause of vertigo, it's essential to have a basic understanding of how the vestibular system works. Based on this understanding, answering some basic questions can help determine the cause of acute vertigo.
Benign paroxysmal positional vertigo (BPPV)
Is the vertigo provoked by a change in head position? If so, the cause may be benign paroxysmal positional vertigo (BPPV), one of the most common causes of vertigo. The disorder is caused by a small crystal called an otolith, which normally sits out of harm's way in the center of the middle ear (the utricle and saccule). In BPPV, an otolith breaks free and enters one of the three canals that usually signal that our body is turning in space. The crystal causes pressure changes in the canal that tricks the body into believing it is turning, even when it's standing still. The resulting confusion causes vertigo.
The vertigo of BPPV tends to occur in brief episodes and is brought on by head turning, because shifting the head can cause the otolith to move in the canal, triggering faulty signals to the brain. A series of particular head maneuvers can be used to reposition the otolith out of the canals where it can't cause any more discomfort.
For more information about BPPV, read here.
If the vertigo is not provoked by a change in head position, the most likely candidates include Meniere's disease, vestibular migraine, transient ischemic attacks, and vestibular paroxysmia. Less common causes include perilymphatic fistulas, autoimmune inner ear disease, otosclerosis, or medication side effects.
Spells that last less than a minute or so are frequently due to BPPV. Longer spells of acute vertigo may be due to a problem in the inner ear, such as a peripheral vestibulopathy or Meniere's syndrome, or to central vertigo, meaning a problem with the brainstem such as can be found in stroke or vestibular migraines.
The inner ear contains a membranous sac which floats within a thin layer of fluid. Inside that sac is more fluid, but of a different kind. Meniere's disease is thought to be caused by an imbalance between the fluid space inside the sac and the fluid outside the sac, with too much fluid building up inside. This is known as endolymphatic hydrops.
The disease usually comes on between the age of 30 and 50 years, and causes attacks of vertigo, hearing loss, and a ringing in the ears. In contrast to BPPV, attacks can last 20 minutes to several hours at a time. As with other forms of vertigo, nystagmus will likely be present. The attacks can vary from anywhere between several times a week to less than once a year. After 5 to 15 years, the dizziness becomes less severe but more constant, and hearing loss can become permanent, though complete deafness in the affected ear is rare.
Meniere disease can be diagnosed by a physician without any additional tests, but audiometry is sometimes useful. No treatment has been found to stop the progressive changes in the inner ear, but medications can help with symptoms when they occur.
For more information about Meniere disease, read here.
This disorder goes by many other names, including vestibular neuronitis, labyrinthitis, neurolabyrinthitis, and acute peripheral vestibulopathy. The disorder usually resolves completely on its own, but causes very uncomfortable vertigo in the meantime. The disorder is thought to be due to inflammation of the vestibular nerve provoked by a virus. There's actually only minimal evidence to support this theory, however: the diagnosis is usually done clinically without further diagnostic tests, though testing may be done to exclude other causes, such as a stroke. The vertigo usually resolves within a few days, but sometimes there is mild residual imbalance that lasts for months. It is not clear that any particular treatment is useful, though many doctors will prescribe a short course of prednisone based on sparse data supporting the practice.
Sometimes vertigo attacks only last a few seconds at a time, but may occur many times a day. Some physicians believe that this may be due to a blood vessel pressing on the eighth cranial nerve, which leads to feelings of vertigo. Other physicians have criticized the lack of good data to support this theory. For example, up to 20 percent of healthy people also have blood vessels that contact the vestibulocochlear nerve. Some have suggested that surgery can be used to remove the pressure placed on the nerve by blood vessels, but others have found that a low dose of carbamazepine may also help. In the setting of uncertain evidence for the blood vessel being a problem, use of medication is the best initial treatment.
While the preceding causes of vertigo cause what is called peripheral vertigo, meaning that the vertigo is caused by something outside the brain and brainstem, it is also possible to get vertigo from problems within the brain itself, which is called "central" vertigo. One of the least serious causes of this central vertigo is a vestibular migraine.
Migraines are usually thought to cause headache, but atypical migraines can actually cause almost any transient neurological symptom, including weakness, tingling, numbness and dizziness. A headache, however, is technically required to make the diagnosis of vestibular migraine. Other symptoms of a migraine, or onset of vertigo with typical migraine triggers, can be helpful in making the diagnosis.
Vertebrobasilar Transient Ischemic Attack (TIA)
The brainstem receives most of its blood supply via what is called the posterior circulation. Two vertebral arteries come together to form the basilar artery, which sends branches that send nourishing blood to the brainstem and back of the brain.
If arteries in the brain are temporarily blocked by a blood clot, the brain cells can begin to starve. If the blood clot dissolves, symptoms improve, and the event is called a transient ischemic attack. If the blood clot remains, then it leads to a stroke with permanent deficits.
Because the brainstem contains our body's centers for balance, including the relays for all information sent to the brain from the inner ear, vertigo is a common symptom of posterior circulation. More concerning, though, are other important functions of the brainstem, such as breathing, movement, and more. For this reason, symptoms of concern for vertebrobasilar TIA are considered a warning of potential bigger problems to come.
Fortunately, it's rare that a vertebrobasilar TIA will only cause vertigo and nothing more. The brainstem is a small area about as big as your thumb, and is packed with important nerves. If damage is done to one part of the brainstem, others will likely also be affected, leading to additional neurological symptoms. For this reason, doctors are keen to find signs of "central" vertigo, meaning vertigo that stems from the brainstem rather than vestibular nerve or inner ear.
Risk factors for vertebrobasilar TIA are almost identical to those for other forms of ischemic vascular disease, such as stroke. For more information about determining if your vertigo is serious, read: when Dizziness Is Serious.
In general vertigo is not a symptom that should be ignored. While it is usually not due to something like a stroke or transient ischemic attack, it is important to be know for sure so that worse problems do not arise. Furthermore, vertigo is extremely uncomfortable, and there are techniques and medications that can help if someone seeks the proper medical advice.
Baloh RW. Clinical practice. Vestibular neuritis. N Engl J Med 2003; 348:1027.
Lempert T, Recurrent Spontaneous Attacks of Dizziness, Continuum 2012 18(5)1086-1101.