CERVICAL VERTIGO – PATHOPHYSIOLOGY AND DIAGNOSIS

Cervical vertigo is a vertigo or dizziness that is provoked by a particular neck posture For example, dizziness provoked by turning the head about the vertical axis, while sitting upright no matter what the orientation of the head is to gravity. A pathological nystagmus, occurring during turning of the trunk in relation to the head, which is held stationary in space, clearly points towards a cervical origin of vestibular vertigo. Such a cervical nystagmus may have a vascular origin by the compression of the vertebral arteries, or a proprioreceptive origin via the upper neck joints, or it may possibly be due to functional disturbances of the upper cervical spine

The usual symptoms are dizziness associated with neck movement.

Persistent unsteadiness

Hearing is not affected. Tinnitus may be present.

Ear pain from referred from the cervical spine may be present.

Visual disturbances on shaking his head forcefully, a spot in the vision, sudden lost vision in one half of the visual field attributed to poor circulation to the back of the brain (diagnosis suggestive

of vertebral basilar compression).

Positional vertigo elicited by turning the head to the sides, accompanied by ear fullness, and at one point

Symptoms can be triggered off by standing up, rapid head movements, walking in a dark room, not eating, exercise, and coughing or sneezing can trigger symptoms.

The causes of cervical vertigo may be:

1. Cervical cord compression – In this case, the ascending or descending tracts in the spinal cord that connect with the cerebellum, vestibular nucleus or vestibulospinal tracts are compressed by disk prolapse, spondylitis, spondylolisthesis, atlanto axial joint dislocation, spinal canal stenosis, neck surgery and chiropractic manipulation are all potential precipitants of neurological symptoms including stroke. This may be painless. This is the most common mechanism of cervical vertigo. (Hain).

2. Vascular compression – There are two distinct mechanisms here – compression and dissection.

The vertebral arteries in the neck can be compressed by the vertebrae (which they traverse), or other structures, the causes being similar to the above. . Arthritis, neck surgery, Dissection can occur at the points where they are anchored in the upper cervical spine, by a stretching force. Hence it is dangerous to volunteer for chiropractic treatment of vertigo that includes “snapping” or forceful manipulation of the vertebrae in persons with unstable necks.

Whiplash (flexion-extension injuries to the neck, usually associated with an auto accident involving a rear end collision) and patients who sustain closed-head injuries may experience late onset symptoms of dizziness, vertigo and disequilibrium possibly due to stretching of the upper portions of the vertebral arteries.

Neck injuries have increased in most parts of the world with auto accidents, presumably due to interaction between use of seat-belts and chest restraints. While chest restraints reduce the risk of death, mechanically by restraining the trunk, they can be associated with greater relative movement of the unrestrained head on neck due to simple biomechanics involving momentum transfer.

3. Abnormal sensory input from neck proprioceptors. (Cervico- vestibular-ocular reflex) Sensory information from the neck is combined with vestibular and visual information to determine the position of the head on the neck and space. It is possible that some individuals are more sensitive than others, and also that neck inputs interact with other causes of vertigo. If sensory information from the neck is unreliable or absent.

Before assuming a cervical origin of a vestibular vertigo, an examination for cervical nystagmus should be carried out by the Head-turning upright test. Such a cervical nystagmus is the only definite pointer towards a relation between an upper cervical spine syndrome and vertigo

Cervical nystagmus caused by proprioceptors of the neck (Reker U).

Examination shows that nystagmus occurs during the turning of the head in relation to the body. In the extreme positions, the proprioreceptive nystagmus does not persist.

Contrary to this, a cervical nystagmus due to vascular causes shows a latency period of 20 to 30 seconds after torsion of the neck, increases and persists if the head remains in the extreme position.

4. Cerebrospinal Fluid (CSF) leak due to tear of cervical root sleeve with dizziness and headache For example, a whiplash injury may tear a cervical root sleeve causing low CSF pressure and hearing symptoms. CSF leaks can cause low-tone sensorineural hearing loss, resembling bilateral

Meniere’s disease.

DIAGNOSIS OF CERVICAL VERTIGO:

Criteria used to diagnose Cervical Vertigo

• Lack of reasonable alternatives.

• Positional testing with ENG in the sitting up position on head turning to the left, right, up and down with eyes closed

• Abnormal cervical MRI with disk abutting cervical cord, or readily apparent high-cervical disease.

A combination of criteria must be used to diagnose cervical vertigo (Hain).

First, one excludes other causes of vertigo such as vestibular neuritis, BPPV, Meniere’s syndrome, central vertigo, post traumatic vertigo (whenever a history of head injury is present), psychogenic vertigo (often including malingering when there are legal issues), and medical causes of vertigo. There should be a sufficient cause of neck injury (whiplash injury or severe arthritis). Symptoms elicited by massage of the neck or vibration to the neck add to the clinical suspicion.

Audiogram and Impedance testing are usually normal. Referred ear pain (otalgia), as part of the ear is supplied by sensory afferents from the high cervical nerve roots, may be complained of..

On physical examination, there should be no spontaneous nystagmus, but there may be positional nystagmus. Many patients who have vertigo in the context of neck disease have a BPPV type nystagmus on positional testing. This suggests that the neck afferents may interact strongly with vestibular inputs derived from the posterior canal.

Often it is helpful to compare nystagmus elicited with the head prone to with the head supine, as if the nystagmus does not reverse, cervic al vertigo seems fairly certain.

Head-turning upright test. (The vertebral artery test)Another useful maneuver is to turn the head to one side to the limit of range, while the examinee is upright and simply wait for 30 seconds. The figure below shows a weak positive and the movie below in the case section shows a strong positive. Clinically, nystagmus that changes direction according to the direction of the head on neck, rather than with gravity, makes cervical vertigo likely. Persons who are positive on this test often have a disk abutting their cervical cord, generally at C5-6.

Examination shows that nystagmus occurs during turning of the body in relation to the head (“phasic neck reflex”). On the other hand, when remaining in the extreme positions, the proprioreceptive nystagmus does not persist. Contrary to this, a cervical nystagmus due to vascular causes shows a latency period after torsion of the neck and increases if the head remains in the extreme position.

Before assuming a cervical origin of a vestibular vertigo, an examination for cervical nystagmus should be carried out. Such a cervical nystagmus is the only definite pointer towards a relation between an upper cervical spine syndrome and vertigo, which is sometimes assumed rather uncritically.

Spontaneous nystagmus recording (Head centre) (Upright position) (Patient M.M)

Cervical nystagmus recorded with head turned left (Upright position) (Patient M.M)

Laboratory studies: If cervical vertigo still seems likely after excluding reasonable alternatives, one next needs to look for positive confirmation. Routine studies in working up cervical vertigo

• Computerized ElectroNystagmography (CENG)

• Audiogram and Impedance studies

• MRI-neck (see above) and MRI-brain

• Flexion/extension x-rays of neck

• CT-angiography (if MRI-neck is negative or there is strong suspicion of vascular etiology, given that renal function is adequate for use of large amounts of iodine contrast)

Angiography: CT-angiography has been rapidly improving in recent years and it is excellent for detection of vertebral hypoplasia — which is as much as you may be able to determine anyway. Three-dimensional reconstructions can be very helpful.

The “gold standard test” for the cervical vertigo due to compression of the vertebral arteries is selective vertebral angiography with the head turned to either side. This, however, is a risky procedure by itself, often it is decided not to proceed to this step. There is also another problem — tiny risk of a stroke during a radiographic procedure, radiologists may simply choose not to turn the head. They will refuse to turn the head to end rotation to diagnose it.. Thus, in some settings, it may be simply impossible to diagnose vertebral artery occlusion because of radiologist risk aversion.

Our position is that one should not attempt vertebral angiography, but simply do CT-angiography as long as kidney function is adequate.

Other tests:

Ordinary MRA and vertebral doppler procedures are rarely abnormal, and sometimes are used as a screening procedure to decide whether vertebral angiography is necessary. We are unenthusiastic about this as it seems unreasonable to us to use methods that are unreliable as screening procedures.

An MRI scan of the neck and flexion-extension X-ray films of the neck are suggested in all.

Fluoroscopy of the neck may be used in persons with abnormal flexion-extension views.

CENG testing is mandatory, largely to exclude alternative causes.

Vertebral artery doppler may be helpful in some.