Question: “A friend of mine has been housebound for 2 months with Vertigo… Do you know anything about a virus that can cause Vertigo?”

Answer: Yes vertigo can be very debilitating and can be caused by a virus. However, there are other potential causes of vertigo, each with different implications.

I recommend going to an ENT specialist or neurologist to help determine the specific cause and therefore the appropriate treatment.  

Definition:

• Vertigo is a term that is sometimes inappropriately used as a synonym for dizziness. In reality vertigo is a relatively specific symptom that refers to the sensation of spinning and/or rotation (vertigo is from the Latin verto which means to turn).
• Dizziness on the other hand is an imprecise term that is often used by patients an attempt to describe a variety of symptoms including light-headedness, faintness, confusion, tingling, unsteadiness, trouble walking, giddiness as well as a spinning sensation. Each of these potential symptoms have dizzying list of far reaching implications. Because of the lack of specificity and potential associated diagnostic confusion, doctors generally don’t use the term dizziness. As you can imagine, interchanging the term vertigo and dizziness can lead to erroneous conclusions and treatments.

Overview:

• There is a complicated series of parts in your head that work together to give you balance and self orientation. This set of parts is known as the vestibular system. When a part of this system is damaged or disturbed it can give you the symptom of vertigo.

Vestibular system:

• There are many parts to this complicated system, but I think it is easiest to think of it as two major parts: Let’s call it the 'inside part' and the 'outside part.'
• The more 'outside part' is a labyrinth of tiny tubes in your middle ear that include the semicircular canals.
• The 'inside part' includes the nerves that carry the sensory information from the labyrinth to the brain, and the brain itself.
• Each part of this system can be damaged in different ways.

What it looks like:

• I did some medical art of the labyrinth recently for a friend’s text book. I guess since I created the image, it is safe for me to put it up here in order to help with the description (see picture below).
• The whole thing is really tiny and imbedded in the skull bone.
• Most people have two of them; one set in each middle ear.
• The semicircular canals are the three different long loop looking things in the picture.
• The curly thing is the cochlea which is the hearing part of the middle ear.
• The whole labyrinth is hollow and filled with fluid. The fluid is called endolymph.
• The inside walls are covered with millions of tiny sensory hairs.

Artwork by Thomas Osborne, MD.

In the next edition of "Head and Neck Imaging" by Peter M. Som and Hugh D. Curtin

How it works:

• When you move your head the fluid moves around inside the labyrinth.  This fluid motion triggers the tiny sensory hairs inside. Moving your head right to left will cause fluid to move in one area more than another area. Front to back movement will cause other areas to have more fluid movement. Etc.  
• Now looking back at the image (above) you can see that the semicircular canals are set up at right angles to each other. This orientation is the most efficient design to decipher 3D spatial angulations.
• Fluid motion triggers the sensory hairs in the different parts of the labyrinth. That information is sent to the brain via a specific nerve (the eighth cranial nerve aka the vestibulocochlear cranial nerve).
• The eighth cranial nerve then plugs into the brainstem where a lot of other vital information is processed. Additional nerves connect back and forth from the brainstem for additional processing and verification with other sensory input.

Problems:

• An injury to any part of this system can cause vertigo. There is a long list of potential causes each with subtle and profound differences.  I will address some of the more common causes.

Infection:

• Many different types of infections can target the labyrinth; a general term for infection or inflammation of the labyrinth is called labyrinthitis. However, most causes are thought to be viral.
• An infection can cause abnormal activation of the nerve hairs in the labyrinth. This haphazard activation will be interpreted by the brain as motion when there is no motion.
• This can further confuse the brain when sensory input from the eyes do not verify that spinning is actually occurring. To this end, vertigo can be worse when you close your eyes and there is less correct sensory input from the eyes to combat the incorrect input coming from the labyrinth.

Benign paroxysmal positional vertigo (BPPV):

• This is a common problem which is typically made worse by a particular head position.
• There are tiny calcium crystals known as otoconia (stones) in a part of the labyrinth known as the utricle. In patients with BPPV, the crystals migrate into one of the semicircular canals and cause problems when they abnormally trigger the sensory hairs in their new abnormal location.
• Specific movements of the head can diagnose the problem (Dix-Hallpike maneuver).
• Other specific head maneuvers can guide the stones away from locations in the labyrinth that cause problems (Epley maneuver, and the liberatory or Semont maneuver).
• These maneuvers can be taught to the patient or patient’s spouse/partner/friend so it can be done at home if/when symptoms come back.

Drugs:

• Some toxins such as drugs or alcohol can target the labyrinth. One common class of drug are aminoglycoside antibiotics.

Injury:

• A fracture that goes through the temporal bone and labyrinth can disturb the delicate balance and cause vertigo. However, if you did something to fracture that hard bone, the diagnosis should not be a dilemma.

Ménière disease:

• Although there is some controversy as the exact cause of Ménière disease, most believe it is caused abnormal/impaired drainage of endolymph.
• Symptoms are somewhat variable but classic symptoms include vertigo, symptoms of ringing in the ear, hearing loss and a sensation of fullness in the ear.
• Attacks of vertigo can be severe, incapacitating, and unpredictable.  However, with Ménière disease symptoms of vertigo rarely last up to 24 hours.
• Ménière disease is usually a diagnosis of exclusion (only diagnosed when all other causes have been ruled out).

Tullio phenomenon:

• Tullio phenomenon is sound induced vertigo.
• This is caused by a bony defect that results in abnormal flow of endolymph.
• Loud noises causes pressure changes in the labyrinth and when there is a bony defect, fluid moves more than it should. Abnormal endolymph motion = vertigo.

Schwannoma:

• A schwannoma is a specific type of slow growing tumor that can press on the eighth cranial nerve and therefore cause nerve malfunction. This process usually causes a slower onset of more mild vertigo, often with additional symptoms of hearing problems.

Brian injury:

• Injury to the brainstem or cerebellum (where the sensory information is processed) can also cause vertigo. A stroke will result in acute systems which needs to be treated as an emergency. Other diseases such as multiple sclerosis, Lyme disease and tumors can cause acute or slower onset of symptoms.

Vertebrobasilar insufficiency:

• Decreased blood flow to the brainstem and/or cerebellum without a stroke can also cause vertigo. This can be a warning sign of a potential future stroke.

Psychogenic vertigo:

• Psychogenic vertigo is vertigo in public places. This is often associated with Agoraphobia (fear of open spaces, crowds, leaving home).

Treatment:

• Treatment depends on the specific type of problem causing the vertigo. Example: BPPV can be treated with specific head maneuvers, Lyme disease is treated with antibiotics, schwannoma can be treated surgically, etc.
• The right diagnosis will lead to the right treatment. A through neurologic exam from a qualified doctor is essential. I recommend going to an ENT specialist or neurologist. Additional testing may also be needed to confirm suspicions or rule out other possibilities.
• Obviously the ideal goal is to fix the root cause; however, sometimes this is not possible. 
• Medications that treat the symptoms of vertigo can help patients cope during and after the medical evaluation. The following medications may help.
• -Antihistamines: Meclizine, dimenhydrinate, promethazine
• -Anticholinergics: Scopolamine
• -Tranquilizer: Diazepam