Crystal sickness or Benign paroxysmal positional vertigo (BPPV) is a common cause of dizziness and vertigo, characterized by sudden feelings of spinning, falling or "the world spinning". The attacks can be severe, but usually short, following specific head movements. It can result in difficulty standing, balancing, walking and can lead to nausea and vomiting. BPPV can range in severity from mild to disabling, and can cause significant anxiety and frustration.
How common is benign paroxysmal positional vertigo?
BPPV is a relatively common disease, accounting for approximately 30% of diagnoses in people who experience dizziness. It is estimated that up to 50% of people will experience BPPV at some point in their lives, and the prevalence increases with age.
What are the symptoms of benign paroxysmal positional vertigo?
The main symptom of BPPV is a feeling of spinning or falling that occurs after tilting or turning the head. It can be experienced as short seizures after movements of the head. It can also lead to problems with coordination, difficulties with balance and walking, and problems with sudden movements. People with BPPV may experience dizziness, disorientation and feelings of fainting. Nausea, vomiting and challenges getting out of bed without losing balance are common. BPPV can also lead to cognitive difficulties, such as brain fog. In some cases, severe anxiety and panic attacks can be the primary symptoms of BPPV.
What causes BPPV?
Crystal sickness occurs due to a disturbance in the vestibular system in the inner ear. The system consists of the otoliths and the vestibular canals.
The otoliths are specialized receptors in the vestibule, a fluid-filled part of the inner ear. They detect the position of the head in relation to gravity, for example when the head bends. The otoliths contain small calcium crystals called otoconia, which cause hair cells to bend against gravity. When the hair cells bend, they send signals to the vestibular nerve network, which sends information to the brainstem, cerebellum and brain. This means that the brain is always aware of the position of the head in relation to gravity.
The inner ear also has membranous canals called the vestibular labyrinth, including the semicircular canals. These canals are also filled with fluid and contain specialized hair cells. When the head moves, it takes some time for the fluid in the semicircular canals to start moving due to the inertia. This movement bends the hair cells and sends signals through the vestibular nerve network to the brain, which provides information about the position and direction of head movement.
In BPPV, the otoconia crystals can detach from the vestibule and flow into the semicircular canals where they do not belong. This disrupts the normal function of the canals, which should only respond to head movement. When the loose otoconia crystals enter the canals, changes in the position of the head can cause them to float towards the bottom of the canal. This causes fluid movement inside the canal, which bends the hair cells and creates a false sense of movement and symptoms of BPPV.
What are the effects of crystal sickness?
BPPV is usually a mild condition that often goes away on its own. It occurs when the head is in certain positions, such as leaning backwards in a dental chair or stretching the head while washing hair. Many people with BPPV feel fine when they wake up, but when they roll over onto their side, a feeling of dizziness or falling occurs after a few seconds.
Sometimes BPPV can persist and become a long-term problem, and in severe cases it can lead to disability. This happens especially when multiple canal systems are involved.
When BPPV persists over time, the brain can adapt to the erroneous signals from the affected vestibular tract. Dizziness occurs when there is a difference between the signals in the vestibular system and from the eyes or body. In BPPV, the signals from the affected semicircular canal do not match the other signals, creating the sensation of dizziness. Eventually, the brain learns to ignore the erroneous signals and accepts them as normal. However, this does not necessarily mean that all symptoms disappear when BPPV is compensated. It is common for people with long-term BPPV to experience primary problems such as anxiety, panic disorder, cognitive difficulties, headaches, memory problems and various other neurological symptoms.
Treatment
BPPV is usually treated using repositioning maneuvers, which involves moving the head through a series of positions to guide the crystals back to the correct location. The most common form of BPPV involves otoconia in the posterior canal. Previously, BPPV was considered incurable and surgical destruction of the vestibular nerve network was the treatment option. However, the late Dr. John Epley, a renowned neurologist developed the Epley maneuver specifically to reposition otoconia in the posterior canal. This maneuver involves holding the patient's head in sustained positions that allow the crystals to return to the correct location. The Epley maneuver has revolutionized the treatment of vertigo and has brought relief to millions of people.
For simple cases of BPPV, a single Epley maneuver may be sufficient. More complex cases may require multiple maneuvers. When the lateral or superior semicircular canals are involved, different types of repositioning maneuvers are required. Severe cases often involve multiple canal involvement, which is common after head injuries such as concussion.
