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A basic question in the neurological history is whether symptoms can be triggered by a certain action.
Neurologists encounter a variety of neurological disorders triggered by head and neck movements. Because the neck is highly mobile, and the neck contains many structures that can produce neurological symptoms, such as arteries, nerves, spinal cord, and support for the head, including vestibular organs and cerebrospinal fluid pathways.
Symptoms can occur due to three mechanisms: obstruction of fluid flow, compression of structures, stretching or tearing of tissues. Sometimes these mechanisms may overlap with each other, and symptoms may also be caused by unknown mechanisms.
The main symptoms can be divided into: dizziness, syncope, or pain/abnormal sensation.
A variety of conditions are covered, including common conditions such as benign paroxysmal positional vertigo, as well as less common conditions such as arterial compression syndrome leading to stroke or fainting, intraventricular mobility masses, and drug withdrawal states. and some uncommon manifestations and important mimics.
Some controversial disease entities are discussed, as well as the risk of misattribution of symptoms based on incidental findings of imaging abnormalities.
In the first part, I will introduce the vertigo part.
01
vertigo
Benign paroxysmal positional vertigo
BPPV is the most common disorder of the vestibular system; Approximately 1 in 42 people will experience the disease. The possible cause is debris within the semicircular canals that obstructs the flow of fluid.
Most BPPV originates in the posterior canal (approximately 80% to 90%), horizontal canal BPPV is less common (about 10%), and anterior canal BPPV is very rare (1% to 2%).
Diagnostic criteria require recurrent episodes of transient (<1 minute) vertigo with a sense of instability, nausea, and vomiting triggered by specific movements, particularly when lying down or turning over; Dizziness on awakening is a typical symptom.
Atypical symptoms can make diagnosis challenging, such as:
1) Some people may complain of neck pain because they adopt a fixed position to avoid vertigo episodes. However, neck pain requires caution for other causes (eg, arterial dissection), which requires further investigation.
2) Patients may complain of vertigo lasting from a few minutes to a few hours. This may be an overestimation of the duration of vertigo (because the sensation of vertigo is extremely unpleasant when it occurs); or persistent, less intense symptoms; Or a series of successive episodes of vertigo. However, a longer duration may indicate other conditions, including transient ischemic attack (TIA).
3) Older adults are less likely to experience typical symptoms of vertigo and are instead described as a vague sense of instability or shaking.
Irritating manipulation can elicit the characteristic nystagmus that accompanies symptoms. The Dix-Hallpike test does not elicit horizontal semicircular canal BPPV, so a roll-on test should be performed in cases with a negative Dix-Hallpike test. Patients must keep their eyes open even if they feel dizzy during the test, as the diagnosis is based on nystagmus rather than the symptoms themselves.
Once the diagnosis is confirmed, corrective maneuvers are usually effective and are best performed immediately. Patients can also practice at home. Vestibular sedatives are best avoided because they can interfere with the natural recovery of the vestibular system. If symptoms persist, it's best to reassess to make sure the diagnosis is correct.
BPPV has some important mimics. One of the most important to watch out for is central vertigo, particularly TIA and stroke. Fortunately, central lesions are often accompanied by brainstem or cerebellar dysfunction. One emergency department study found that only 0.7% of patients with isolated vertigo/dizziness had a central cause.
In other conditions, such as vestibular neuritis and vestibular migraine, vertigo is exacerbated by head movements. The difference is that vertigo in BPPV is intermittent and asymptomatic between episodes—not exacerbated by persistent underlying vertigo with exercise.
Hunter's bow syndrome
Bow hunter syndrome describes a rare clinical syndrome that causes mechanical compression or occlusion of the vertebral arteries when the neck is rotated or extended.
The name comes from the fact that the hunter experienced symptoms such as dizziness, vomiting, and nystagmus when he turned his head to draw a bow and shoot an arrow, hence the name of this image.
The vertebral arteries can be compressed at the foramen, usually due to bone spurs; Herniated discs and degeneration of the vertebral bodies are also possible causes. In most people, one vertebral artery is the dominant side, and if this artery is compressed, the non-dominant side may not be able to maintain adequate perfusion, resulting in ischemia.
A review of 153 cases found that the left vertebral artery was most commonly affected, with the most common sites of compression being in segments C1 to C2.
Vertigo and other brainstem/cerebellar symptoms or syncope may be noted during the history when the neck is rotated contralaterally.
Imaging modalities include dynamic ultrasound imaging or angiography. CT scans may show skeletal abnormalities. Degenerative lesions of the spine are so common that neurologists should be careful not to diagnose hunter's bow syndrome based on imaging findings alone, but must combine them with clinical symptoms or may miss other treatable causes.
Regarding treatment, there is little more evidence beyond standard TIA/post-stroke management measures. Postures that trigger symptoms (including wearing a collar) appear reasonable for a short period of time, but it is unclear how long they need to be avoided. Some patients may undergo surgery to correct bone abnormalities or have a stent implanted.
Vestibular paroxysmals
Vestibular paroxysmia is a relatively rare condition, but because it is treatable, it is worth recognizing. In one study, vestibular paroxysmal disorders accounted for 3.9% of patients presenting to the dizziness clinic.
Vestibular paroxysmal is caused by compression of the vestibular nerve (eighth cranial nerve), resulting in spontaneous discharges (similar to trigeminal neuralgia and facial spasms). Causes include neurovascular conflicts and tumors, and sometimes no exact cause can be found.
A vascular ring creates neurovascular conflict by compressing the vestibular component of the eighth cranial nerve. This results in characteristic symptoms, including sudden episodes of vertigo. AICA: anterior inferior cerebellar artery; ASA: anterior spinal artery; PCA: posterior cerebral artery; PICA: posterior inferior cerebellar artery; PCOM: posterior communicating artery; SCA: superior cerebellar artery.
The main symptom of the patient is recurrent spontaneous episodes of vertigo, which last a short time (from a few seconds to 1 minute), have frequent episodes, and respond to treatment with carbamazepine or oxcarbazepine.
This vertigo may be spontaneous or triggered by head movements. Crucially, it is not caused by a technique that induces BPPV.
Hyperventilation may induce vertigo and nystagmus. A form known as typewriter tinnitus may coexist with it, which helps identify the affected side.
Neurovascular conflict may also be found in asymptomatic populations (35% in one study), as well as on the unaffected side of patients with vestibular paroxysmals, which poses a diagnostic challenge. In fact, imaging findings are not part of the diagnostic criteria, and the diagnosis is based on clinical findings.
Unlike BPPV, vestibular paroxysmal disorder is a chronic condition with a significant seizure burden. Carbamazepine/oxcarbazepine may be an effective treatment option, which is also a diagnostic. Microvascular decompression surgery may be helpful, but current recommendations are to consider decompression surgery only if medical therapy is ineffective, as vasospasm and infarction may occur.
Vertebrobasilar insufficiency
Vertebrobasilar insufficiency is a general term used to describe TIA/stroke in the posterior circulation, and specifically to haemodynamically induced posterior circulation ischemia symptoms (e.g., vertigo, ataxia) that may be exercise-induced; In these cases, the arterial diameter may be reduced by narrowing of the lumen due to external compression or movement, and collateral circulation is poor.
The concept and diagnostic criteria for vertebrobasilar insufficiency are controversial because it involves a variety of possible pathological mechanisms.
Typically, BPPV is the more common cause of vertigo when the head moves. Sometimes tests suggest arterial stenosis, which may be incidental and carries the risk of misattributing symptoms to vertebrobasilar insufficiency. In one large study, asymptomatic significant (>50%) vertebral artery stenosis accounted for 7.6% of the population (1% for bilateral stenosis).
When evaluating a patient, the physician needs to carefully distinguish whether exercise-induced vertigo symptoms are truly related to vertebrobasilar insufficiency.
In the absence of external compression, if vertebrobasilar insufficiency is caused by neck movement, this usually indicates the presence of extensive arterial stenosis. People with symptomatic vertebrobasilar stenosis have a higher risk of stroke and therefore require secondary prevention.
Cervical vertigo
Cervical vertigo, also known as cervical vertigo/dizziness and proprioceptive vertigo, is controversial. One possible cause is disturbance of proprioceptive information transmitted through the neck.
Both cervical spondylosis and vertigo are common, so there is a risk of misattributing both; More common causes are usually more plausible. One review noted that the lack of a test to prove whether cervical spondylosis caused vertigo puts clinicians in a position where they are "unable to prove or deny the diagnosis".
There is disagreement among neurologists and physiotherapists about the acceptance of this disease entity and the available literature. Depending on the view, cervical vertigo is either very common in people with vertigo, extremely rare, or non-existent.
In summary, cervical vertigo is a controversial concept and is a diagnosis of exclusion; Clinicians should carefully consider alternative explanations. There are currently no guidelines, so its management depends on the physician's discretion.
Bruns syndrome