Ballistically Potent Vertigo

aka Neurological Mind-boggler 010

A 50 year-old female presents with an intense episodic sensation of the world spinning around (i.e. more so than usual). Her first attack occurred when she got out of bed. After the attack settled she went to hang her washing out — the same thing happened again. She has no other neurological symptoms and is otherwise well.

She has a positive Dix-Hallpike test.

Questions

Q1. What is the likely diagnosis?

Benign Paroxysmal Positional Vertigo (BPPV)

Q2. What causes this condition?

BPPV is caused by the deposition of calcium crystals within the endolymph of the semicircular canals. This typically occurs in the posterior canal and ultimately results in abnormal stimulation of the vestibular nerve with specific changes in position.  BPPV may occur ‘out of the blue’ or it may occur following surgery, a head injury or an upper respiratory tract infection.

Q3. What are the typical clinical features of the condition?

The features of BBPV include:

  • a history of episodic vertigo lasting seconds, which is only precipitated by sudden movements of the head
    (e.g. looking up, suddenly twisting the head, suddenly getting up from a supine position or when suddenly rolling over in bed)
  • the patient is typically middle-aged or elderly; BPPV is more common in females.
  • the patient may identify a particular movement or position of the head that precipitates vertigo, which usually occurs after a latent period of 10 – 20 seconds
  • vomiting can occur in BPPV, but is often absent.
  • between attacks the patient may experience non-specific nausea, dysequilibrium and dizziness
  • an absence of other neurological signs or symptoms.

Q4. How is a Dix-Hallpike test performed?

The Dix-Hallpike manouevre is performed as follows:

  • support the patient’s head while they are in a sitting position.
  • tell the patient to keep their eyes open and to stare into the distance (avoid fixation).
  • rapidly move the patient into the supine position. The head should be extended 45 degrees, ideally over the end of the bed.
  • Perform this 3 times:
    • first with the head in neutral position.
    • then with the head turned 45 degrees to the left
    • then with the head turned 45 degrees to the right.

Warn the patient you are going to perform a procedure that may bring on their symptoms first!

Q5. What is seen when the Dix-Hallpike test is positive?

A positive Dix-Hallpike test confirms the diagnosis of BPPV.

The following features are seen:

  • Latency of onset
    (usually at least 5–10 seconds)
  • Torsional (rotational) or horizontal nystagmus.
    Upbeating- torsional nystagmus implicates the posterior semicircular canal of the tested side (most common).
    Purely horizontal nystagmus implicates the horizontal semicircular canal of the tested side.
    Downbeating-torsional nystagmus implicates the anterior semicircular canal of the tested side.
    Purely vertical or purely torsional nystagmus suggests a central cause.
  • Fatigable nystagmus.
    The nystagmus showed fatigue in less than 1 minute. Multiple repetition of the test will result in less nystagmus.
  • Reversal.
    Upon sitting after a positive maneuver the direction of nystagmus should reverse for a brief period of time (“unwinding nystagmus”).

Q6. What is the treatment for BPPV?

BBPV is a self-resolving illness. However sometimes it can last up to 6 months! About half of people have a recurrence within 5 years.

A more rapid cure may be obtained by performing manoeuvres aimed at displacing the deposited otoliths. Canalith repositioning manoeuvres are effective about 80% of the time for BBPV (about twice as effective as placebo!). They include:

  • The Epley manoeuvre (aka the Nylen-Barany manoeuvre)
  • The Semont manoeurvre

Following these manoeuvres, some experts advise that the patient should sleep semi-recumbent (at 45 degrees) and avoid provocative manoeuvres for 2 weeks.

Symptomatic patients may also require rehydration and/or treatment of vertigo and vomiting with anticholinergic antihistamines (e.g. promethazine, meclazine or prochlorperazine) and benzodiazpines (e.g. diazepam).

If Canalith repositioning manoeuvres are unsuccessful the patient can be taught to attempt that home or to perform Brandt-Daroff habituation exercises. Rarely, surgical procedures such as semicircular canal occlusion are required for prolonged treatment-resistant cases.

Video showing Brandt-Daroff habituation exercises:

Q7. How is the Epley manoeuvre performed?

For right-sided symptoms the Epley manoeuvre is performed as follows:

  • the patient sits upright with her head to the right.
  • she is rapidly moved to the supine position with her head hanging to the right (as for the Dix-Hallpike test)
  • this position is maintained until the nystagmus fatigues and ceases.
  • her head is quickly rotated to the left, so that her right ear is now towards the ceiling.
  • this position is maintained for 30 seconds.
  • the patient rolls onto her left side, while her head remains rotated to the left, so that her nose points to the floor.
  • this position is maintained for 30 seconds.
  • she is then rapidly returned to the seated position, with her head still turned to the left.
  • the manoeurvre can be repeated until nystagmus is no longer elicited.

Or you may prefer these funky Claymation demonstrations of both the Dix-Hallpike and the Epley manoeuvres:

Q8. How is the Semont manoeuvre performed?

The Semont manoeuvre is an alternative to the Epley. Again, the description given assumes right-sided symptoms:

  • the patient is seated with her head turned 45 degrees to the left.
  • she is tilted so that she is lying on her right side, with her head still turned to the left so that she is looking towards the ceiling.
  • this position is maintained for 1 minute.
  • she is then quickly moved through 180 degrees so that she is lying on her left side with her face pointing towards the floor.
  • this position is maintained for 1 minute.
  • she is then slowly returned to the seated position.

This video demonstrates the Semont manoeuvre (though I’m not sure about the head banging action after the 180 degree flip!):

Q9. When should you suspect central positional vertigo?

Central positional vertigo is caused by a lesion of the cerebellum or the brainstem.

Positional vertigo and nystagmus are common features of a may be present in:

  • Chiari malformation
  • cerebellar tumor
  • multiple sclerosis
  • migraine vertigo
  • degenerative ataxia disorders

A central cause should be suspected if:

  • There is purely vertical nystagmus (e.g. down-beating) or purely torsional nystagmus when the Dix-Hallpike test is performed.
  • nystagmus lasts as long as the position is held (doesn’t fatigue).
  • there is no latency of onset.
  • other cerebellar or brainstem signs are present.
  • canalith repositioning manoeuvres are ineffective.

MRI is the investigation of choice if a central cause is suspected.

This brief video summarises the etiology and assessment of BPPV:

References

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  1. [...] tips and tricks for diagnosing BPV. It ties in nicely with LITFL’s case-based Q&A on Ballistically Potent Vertigo. Dr Smith’s ECG BlogPut on your ECG thinking caps and tackle these cases from Dr [...]

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