bubble_chart Overview

Positional vertigo was renamed cupulolithiasis, which is more common in adults aged 40–60, with a higher prevalence in women. Harrison (1975) reported that in 365 cases, 60% of the causes were unknown. In 1921, Barany first described a 27-year-old female patient who experienced vertigo symptoms when turning her head to the right, attributing it to a lesion in the utricle. Schuknecht (1962) conducted pathological examinations on three cases and found normal sensory epithelia in the utricle, saccule, and cupula of the crista ampullaris, with only basophilic granular deposits in the cupula of the posterior semicircular canal. This may be the cause of gravity-induced sensitivity, hence the term cupulolithiasis.

bubble_chart Pathological Changes

1. It may be due to spontaneous degeneration of the utricle, causing otoliths to detach from the macula and deposit on the posterior cupula.

2. Inflammation or trauma can also induce this condition. For example, during viral labyrinthitis or chronic suppurative otitis media, leukocytes, phagocytes, or endothelial debris may enter the endolymph; in cases of head trauma or stapes surgery, blood entering the endolymph can form particulate matter that deposits on the cupula. Barber reported that 47% of patients with longitudinal temporal bone fractures experience positional vertigo, while 20% without fractures also exhibit this symptom. Dix and Hallpike (1952) found that 26% of 100 otitis media patients had positional vertigo. Ear surgeries such as tympanoplasty or radical mastoidectomy, which injure the vestibular system, can also lead to this condition.

3. Pathological findings by Lindsay and Cawthorne revealed degeneration of the utricle and the superior and lateral semicircular canals, which are supplied by the anterior vestibular artery and the superior vestibular nerve branch, while the saccule and posterior semicircular canal remained normal. They suggested that hypertension, heart disease, and vertebrobasilar artery insufficiency could cause anterior vestibular artery embolism, leading to degeneration and detachment of the otolithic membrane, which then deposits on the cupula.

4. Hypergammaglobulinemia, where globulins deposit on the cupula, or chronic alcoholism causing thinning of the cupula, can also produce this symptom. About half of children with grade III deafness using high-intensity (120–130 dB) hearing aids develop positional vertigo.

Once cupulolithiasis forms, when the head is upright, the posterior semicircular canal cupula becomes vertical. If lying on the affected side, the posterior canal cupula shifts to a horizontal position, and the deposited otoliths, due to gravity, deviate from the cupula, causing stimulation and resulting in vertigo and nystagmus. If inflammatory particles are loosely attached, repeated head movements may dislodge them, eliminating stimulation and leading to fatigue. Conversely, if otoliths are firmly adhered and persistent, repeated positional changes will not reduce the stimulus intensity, resulting in a non-fatigable type. The latter often persists for years, affecting daily life and work, and may require surgical intervention.

bubble_chart Clinical Manifestations

1. The general condition is good, with symptoms such as vertigo, nausea, and vomiting occurring only in certain body or head positions. If the position is changed to the opposite side, the symptoms quickly improve, but they reappear when the original position is repeated. The latency period is generally 2–3 seconds, and the duration rarely exceeds 1 minute. Nausea, vomiting, and cold sweating are uncommon, and falling is even rarer.

2. During vertigo episodes, there is no tinnitus or deafness, and pre-existing cochlear symptoms do not worsen.

3. The condition often resolves within weeks or months, though in rare cases, it may persist for years.

4. During the illness, there is no headache or other central nervous system signs. {|103|}

bubble_chart Diagnosis

1. Positional Nystagmus Test: Have the patient sit on the bed, first in a supine position with the head hanging down. Observe for 10 seconds for vertigo and nystagmus. Then have the patient sit up and observe for another 10 seconds. Next, have the patient lie down with the head turned to one side and observe for 10 seconds, followed by lying supine with the head hanging down to the other side and observing for another 10 seconds. Each change in position, sitting up, or lying down should be completed within 3 seconds. If nystagmus appears in any position, continue observing for 30 seconds. If the nystagmus persists without disappearing, the test is positive. For example, if the right ear is down and the rotational nystagmus is to the right, and vertical nystagmus appears when the eyes gaze to the left, and repeated tests are positive, it is called the non-fatigable type. Conversely, if nystagmus does not reappear upon repeated testing, it is called the fatigable type. If the direction of nystagmus remains unchanged in different head positions, it is called the direction-fixed type; if nystagmus appears in different directions, it is called the direction-changing type. Nystagmus that appears in a single head position, lasts for a short duration, has a latency period, and shows a fatigable response in the direction-fixed type is often due to peripheral sexually transmitted disease. Conversely, it is mostly due to central sexually transmitted disease. Other tests such as visual tracking and optokinetic tests are generally normal.

2. Caloric and other vestibular function tests are normal.

3. Pure-tone audiometry is mostly normal.

bubble_chart Treatment Measures

(1) Conservative Treatment The prognosis of this condition is favorable, and it may resolve spontaneously within about a year without treatment. For individuals with prolonged symptoms, symptomatic therapy can be adopted, such as oral diazepam or vitamin supplements. Forced positional exercises may also be employed, utilizing the fatigue response characteristic by maintaining the triggering position for extended periods daily. Over time, the body adapts, and the sensation of vertigo diminishes. In cases of severe vertigo, intratympanic injection of 4% lidocaine or streptomycin sulfate can yield excellent results.

(2) Surgical Treatment If long-term conservative treatment proves ineffective, vestibular nerve section may be considered. When feasible, selective posterior ampullary nerve section is preferred, as it specifically eliminates abnormal impulses from the crista of the posterior semicircular canal, leading to a cure.

Using a stapedectomy approach via an endaural incision, the tympanic membrane flap is reflected anteriorly to expose the incudostapedial joint and the round window. A diamond burr is used to remove 1–2 mm of bone horizontally from the floor of the round window. To facilitate the procedure, a portion of the posterior external auditory canal wall may be drilled away to improve visualization of the round window. The posterior ampullary nerve lies approximately 1 mm medial to the inner edge of the round window membrane. Under microscopic guidance, the nerve is identified, hooked, and sectioned. The tympanic membrane is then repositioned, and the external auditory canal is packed.

bubble_chart Differentiation

It should be differentiated from the following diseases.

(1) Central positional vertigo: Commonly seen in tumors and vascular lesions of the fourth ventricle of the brain, it may present with headache, nausea, vomiting, and other positive neurological signs. Spontaneous nystagmus is often present, and positional testing reveals nystagmus lasting more than 30 seconds, with no latency or fatigue. CT and MRI can further confirm the diagnosis.

(2) Vestibular neuritis: Sudden onset, which may persist for several days, reduced response to caloric testing, and a history of upper respiratory tract infection. Blood tests may show grade I leukocytosis.

(3) Cervical spondylosis: Osteophytes in the cervical vertebrae may compress the vertebral artery or stimulate the cervical sympathetic nerves, leading to vertebral artery spasm and insufficient blood supply to the vestibular system. This condition is more common in adults over 40 years old, and vertigo episodes are related to specific head and neck positions. It is often accompanied by other symptoms of vertebrobasilar insufficiency, such as headache, visual disturbances, and numbness in the upper limbs. X-rays of the cervical spine may reveal osteophytes or other deformities in the 4th to 6th cervical vertebrae.