Vertigo With an Effective Treatment But an Unknown Cause?

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RESEARCH UPDATE

Neurologists have identified a new type of vertigo called recurrent spontaneous vertigo with head-shaking nystagmus (RSV-HSN).¹ So far, the cause is unknown, though treatment seems to be effective. RSV-HSN appears to be relatively rare, but as a new diagnostic entity the number of people affected remains unknown.

“[Vertigo] can be difficult to diagnose and quite debilitating for people, so it’s exciting to be able to discover this new diagnosis of a condition that may respond to treatment,” senior author Ji-Soo Kim, MD, PhD, of Seoul National University in Seongnam, (South Korea), said in a press release.

Vertigo can be caused by a number of neurological problems that affect the vestibular system of the inner ear, which contributes to balance and coordination. Causes of vertigo can range from benign (like migraine and Meniere disease), to serious (like tumors). However, for a fair number of people the cause is never identified. The term benign recurrent vertigo (BRV) refers to people with recurrent vertigo of unknown cause. BRV is largely a diagnosis of exclusion and relies mostly on clinical symptoms.

Neurologists in South Korea were clued into the new condition in 2004 when they saw a young man with recurrent spontaneous vertigo (RSV), severe motion sickness, and repetitive, uncontrolled eye movements brought on by head-shaking (head-shaking nystagmus, or HSN). However, the patient had no history of migraine or other evidence of vestibular problems that could cause RSV-HSN.

They conducted a study of other patients who presented with symptoms of vertigo in the Dizziness Clinic of Seoul National University Bundang Hospital. Between July 2004 and December 2015, they saw 3990 patients with RSV. Of these, 338 patients had RSV of unknown cause. After performing a battery of neurological tests, they found that 35 of these patients had RSV-HSN, while 303 had BRV. They then compared the RSV-HSN group with 35 patients with vertigo of known cause, such as vestibular neuritis, vestibular migraine, and Meniere disease.

Patients with RSV-HSN had episodes of vertigo that lasted a few minutes to days and ranged from two to three times per week to once a year. They had more severe motion sickness than patients with BRV. In addition, their nystagmus lasted two to three times longer than patients with vestibular neuritis, vestibular migraine, or Meniere disease.

About 20% of patients with RSV-HSN had nystagmus that was more intense than patients with vestibular neuritis. In 71% of these RSV-HSN patients, vigorous nystagmus could be induced with only two to five seconds of head-shaking.

Follow-up and Take Home Points >

Neurologists prescribed preventive medication to in 20 patients with frequent severe RSV-HSN. Medications included nimodipine, betahistine, propranolol, flunarizine, nortriptyline, and acetazolamide. Thirty percent reported partial and 5% reported complete control of symptoms.

During a median follow-up of 11.8 years, over 50% reported resolution or improvement of symptoms. Only one patient reported worsening of symptoms.

In the press release, Dr Kim suggested that RSV-HSN may stem from hyperactivity within the vestibular system. “It’s possible that the vertigo occurs when this unstable mechanism is disrupted by factors either within the person’s body or in their environment,” he said.

Take home points

• Neurologists in South Korea have identified a new type of vertigo called recurrent spontaneous vertigo with head-shaking nystagmus (RSV-HSN)

• Patients with RSV-HSN had worse motion sickness than patients with benign recurrent vertigo

• Patients with RSV-HSN had longer lasting, more intense, nystagmus than patients with vertigo caused by vestibular conditions

• Over a follow-up of almost 12 years, over 50% reported resolution or improvement of symptoms with preventive medication

References:

1. Lee SU, Choi JY, Kim HJ, et al. Recurrent spontaneous vertigo with interictal headshaking nystagmus. Neurology. 2018;90:e2135-e2145.