A. 2 or more spontaneous vertigo attacks1, each lasting 20 minutes to 12 hours
B. At least one episode of vertigo in the affected ear before, during or after the vertigo attack5,6 with low-moderate frequency sensorineural hearing loss confirmed by electroaudiometry3,4
C. fluctuating affected ear symptoms (hearing, tinnitus, stuffiness)7
D. Not better explained by another vestibular disorder8
The ICVD version of the MD diagnostic criteria annotation states (Lopez-Escamezetal, 2015) that
1, Most patients have vertigo episodes as completely spontaneous, but certain patients confirm a diet as a trigger, such as excess sodium or caffeine. Some patients can have episodes of vertigo lasting seconds to minutes induced by high intensity low frequency sounds (Tullio phenomenon) and stress. These episodes tend to occur later in the disease and may be caused by an increase in fluid retention that brings the membrane vagus closer to the pedicles of the stirrups.
2. The duration of the attack may be <20
3. Definition of low frequency sensorineural hearing loss: for every 2 consecutive frequencies below 2000 Hz, the affected ear is at least 30 dB higher than the pure tone threshold of the contralateral ear. bilateral low frequency sensorineural hearing loss: for every 2 consecutive frequencies below 2000 Hz, the absolute threshold of the bone conduction must be 35 dB or higher. Evidence of recovery of low-frequency sensorineural hearing loss at some point in time is more supportive of the diagnosis of MD if there are multiple available electroaudiometric findings. Bilateral simultaneous sensorineural hearing loss (symmetric or asymmetric) can occur in some patients, although there are concerns about the possibility of inner ear autoimmune disease and a preference for migraine as an alternative explanation or comorbidity for vertigo attacks. Bilateral low-frequency sensorineural hearing loss can also be seen in the early stages of non-syndromic progressive deafness (DFNA6/14) caused by mutations in the WFS1 gene, but vertigo attacks have not been associated with this group of mutations. sensorineural hearing loss in MD can also involve the middle and high frequencies after several vertigo attacks, leading to pan-frequency hearing loss.
4. Sensorineural hearing loss can precede vertigo attacks by weeks, months or years. This clinical variant was once called “delayed hydrops”, but the preferred term should be delayed MD, since endolymphatic hydrops is a pathological finding after all.
5. The temporal relationship between hearing loss and vertigo attacks generally refers to changes in hearing within 24 hours of the onset of vertigo, which must be described by the patient. It is usually spontaneous fluctuating hearing loss in the first few years of onset and leads to progressive permanent hearing loss after repeated episodes.
6. The sudden loss of vestibulospinal reflexes can lead to a sudden fall or uncommon lateral tilt that can last for a few seconds or rarely for several minutes (so-called vestibular fall episodes, otolith crisis or Tumarkin otolith crisis).
7. In the first few years the affected ear tinnitus or ear swelling is enhanced during the vertigo attack and the affected ear is identified by hearing loss meeting criterion B. Once the hearing loss becomes permanent tinnitus may also be permanent.
8. The differential diagnosis should include short-onset ischemic attacks, vestibular-type migraine, vestibular paroxysms, recurrent unilateral vestibular disease and other vestibular disorders. MRI may be required to rule out vestibular nerve sheath tumors or endolymphatic sac tumors. Migraine, BPPV and some forms of systemic autoimmune conditions may be considered comorbid, but do not indicate a diagnosis of MD.
Possible MD diagnostic criteria
A, 2 or more episodes of spontaneous vertigo lasting 20 minutes to 24 hours each
B, fluctuating affected ear symptoms (hearing, tinnitus, stuffiness)1
D. Not better explained by another vestibular disorder2
The ICVD version of the MD diagnostic criteria annotation states (Lopez-Escamezetal, 2015) that
1. vertigo attacks must be characterized by fluctuating symptoms. Hearing loss can be fluctuating in the first years of the disease. Increased tinnitus and dullness in the affected ear usually in the first years usually accompanied by vertigo attacks.
2. The differential diagnosis should include short-onset ischemic attacks, vestibular migraine and other vestibular disorders. MRI may be required to rule out vestibular nerve sheath tumors or endolymphatic sac tumors. Migraine, BPPV, and some forms of systemic autoimmune conditions may also be considered comorbid but do not indicate a clinical syndrome of MD.