Dizziness is a very common clinical symptom, but not a single disease, and its etiology involves a variety of diseases such as neurology, otorhinolaryngology, general internal medicine and psychiatry. At the same time, dizziness is a subjective sensation, and there is no definitive objective test that can be used to make a definitive diagnosis or differential diagnosis. Therefore, the correct diagnosis of dizziness comes more from clinical aspects, i.e., the correct definition of dizziness symptoms, the effective identification of clinical features, the correct grasp of different causes of dizziness, and the correct use of various auxiliary examinations.
First, the definition of dizziness symptoms is a prerequisite for correct diagnosis
Dizziness is a non-specific symptom, which can be described in various ways by patients due to culture, education, language of different regions and individual experience. If the patient has difficulty describing the condition, a selective response is used to assist in the determination. Since 1972, the medical community has uniformly classified dizziness into four different symptoms: vertigo, presyncope, imbalance, and light-headedness. Of these, vertigo is an idiosyncratic symptom that refers to the presence of illusions of motion or hallucinations of apparent rotation of surrounding objects or oneself, with the primary etiology being vestibular system dysfunction. Syncope is preceded by a transient feeling of “imminent unconsciousness and fainting” and is basically similar to syncope in its main etiology. Imbalance is mainly a feeling of unsteadiness and loss of balance control when standing or walking, and is associated with a variety of neurological, medical, psychiatric and disease conditions. The sensation of heaviness of the head and lightness of the feet is the most nonspecific, with the sensation of floating of the head or body, which can also be floating, and its etiology is diverse.
It can be seen that only when vertigo or non-specific dizziness symptoms are correctly defined, clinicians can carry out further diagnosis and differential diagnosis, otherwise errors in the whole diagnostic direction will occur.
Second, careful questioning is the key to correct diagnosis
Many clinical studies have proved that correct history taking is the key to clinical diagnosis, and through interrogation it is possible to identify 90% of patients with symptoms of specific vertigo or nonspecific dizziness, and also to clarify the etiology of about 70% to 80% of vertigo [1, 2].
After clarification of vertigo or nonspecific dizziness, a complete picture of the clinical features of the patient’s vertigo or dizziness is required. In vertigo, particular attention should be paid to the following aspects.
(1) form of onset: sudden onset is more often a peripheral vestibular lesion, while chronic or subacute onset is more often a central vestibular lesion.
(2) Symptom level and concomitant autonomic symptoms: vertigo in peripheral vestibular lesions is mostly severe and accompanied by obvious nausea and vomiting, while in central vestibular lesions it is mild and accompanied by mild or no autonomic symptoms.
(3) Course: benign episodic positional vertigo (BPPV) lasts for a few seconds, mostly less than 1 minute; Meniere’s disease, transient ischemic attack (TIA) and migraine-related vertigo last for minutes to hours; vestibular neuronitis and central lesions last for hours to days; and dizziness in people with mental disorders lasts for weeks to months. Doctors must have a better understanding of the various diseases, because the duration of dizziness due to different diseases is not fixed and is not an important basis for diagnosis, other manifestations are even more important.
(4) Frequency of episodes: single episodes are usually associated with vestibular neuronitis or vascular disease; recurrent vertigo should be considered as Meniere’s disease or migraine; recurrent vertigo with other manifestations of the nervous system should be considered as TIA; recurrent positional vertigo should be considered as BPPV.
(5) Concomitant symptoms: ear stuffiness or ear pain is seen in auditory neuroma, otitis media and Meniere’s disease; headache is seen in migraine and auditory neuroma; tinnitus is seen in Meniere’s disease, auditory neuroma and vaginitis; hearing loss is seen in vaginitis, Meniere’s disease, auditory neuroma, peripheral lymphatic leakage and stroke; facial palsy is seen in auditory neuroma and ear herpes infection; imbalance is seen in stroke, vaginitis and vestibular neuronitis; photophobia and phonophobia are seen in migraine; and BPPV is seen in vaginitis. photophobia and vocal aversion are seen in migraine; focal neurological signs are seen in stroke, tumor and multiple sclerosis.
(6) Triggering and relieving factors: change in head position is seen in BPPV, vestibular neuronitis, tumor, peripheral lymphatic leak, and multiple sclerosis; after upper respiratory tract infection is seen in vestibular neuronitis; stress is seen in psychogenic and migraine; after ear pressure, trauma, or sustained exertion is seen in peripheral lymphatic leak.
For nonspecific dizziness, special attention should be paid to the patient’s history of systemic diseases (hypertension, diabetes, various heart diseases, postural blood pressure fluctuations, medication use, anemia, thyroid disease, etc.), mental status (depression, anxiety, somatization disorders, etc.) and neurological diseases (profound sensory disorders, ataxia, multisystem degeneration, etc.).
By mastering the clinical features of these different dizziness or vertigo and by careful history questioning, clinicians can make the correct diagnosis for the majority of patients, which cannot be obtained by any auxiliary examination.
Third, the mastery of different causes of dizziness is the guarantee of correct diagnosis
Since the etiology of dizziness involves multiple systems, it is necessary for doctors of different specialties to have multidisciplinary knowledge and to have the necessary mastery of multidisciplinary diseases involving vertigo or dizziness to reduce diagnostic errors. For example, if Dix-Hallpike examination is routinely performed, it is possible to avoid misdiagnosing a large number of patients with BPPV as cervical vertigo; understanding that the so-called vertebrobasilar artery insufficiency of blood supply (VBI) is a TIA of the vertebrobasilar system [3], it is possible to avoid misdiagnosing a large number of patients with long-term dizziness as VBI.
Clinicians must be aware of the common causes of dizziness or vertigo and not just the diseases of their specialty. Knowing which diseases are the most common causes of vertigo and which diseases are the most important causes of nonspecific dizziness will allow them to maintain a clear diagnostic mind and direction in a busy clinical workload, to rapidly identify and diagnose diseases, and to avoid misdiagnosis, delayed diagnosis, and overexamination due to the inability to distinguish between common and rare diseases.
A study analyzing the proportion of different symptoms in 100 patients with dizziness found that vertigo accounted for 54%, presyncope for 16%, imbalance for 17%, and lightheadedness for 16% [4]. The joint neuro-otologic clinic counted 812 consecutive patients and found that periventricular etiology accounted for 64.7% (mainly BPPV, recurrent vestibular disease, vestibular neuronitis and Meniere’s disease), psycho-psychological for 9.0%, central vestibular for only 8.1%, and unknown causes for 13.3% [5].
A systematic analysis of 12 different studies with a total of 4536 consecutive patients [6] showed that peripheral vestibular causes accounted for 44% (BPPV 16%, vestibular neuronitis 9%, Ménière’s disease 5%, other 14%), central vestibular causes 10% (stroke 6%, tumors less than 1%), psychiatric disorders 16%, presyncope 6%, imbalance 5%, other causes (drugs , metabolism, infection, trauma, etc.) accounted for 16%, and unknown etiology accounted for 13%. Comparing the etiologies of patients seen in general practice or specialized clinics, peripheral vestibular was the most common (43% vs. 46%), followed by non-vestibular non-psychiatric (34% vs. 20%), psychiatric (21% vs. 20%), and central vestibular (9% vs. 7%).
Analysis of the etiology of 5,353 patients in the neurology dizziness clinic [7] showed that 34.4% had peripheral vestibular disease, 19.2% had psychiatric disorders, 13.2% had central vestibular etiology, and 10.3% had migraine-related vertigo.
In our dizziness clinic, we analyzed the etiology of 3270 consecutive outpatients with dizziness and found that psychiatric disorders were the most common (35.8%), followed by periventricular etiology (34.1%, including 83.9% for BPPV), systemic diseases, pharmacological factors or unknown diagnosis (19.9%), and central vestibular etiology (only 10.1%).
Comparing the results of related studies at home and abroad, it is clear that peripheral vestibular etiology and psychiatric disorders are the most important causes of dizziness, with the former being the primary cause of vertigo and the latter being the primary cause of nonspecific dizziness. In China, the proportion of both is higher than foreign data because of the lack of a well-developed general medical system in China, and the large number of patients with BPPV and psychotic dizziness failing to be diagnosed correctly and in a timely manner, resulting in an exceptionally high proportion of them in specialized outpatient clinics in tertiary care hospitals.
It can be seen that vestibular peripheral diseases (especially BPPV) are the most important etiology of vertigo, and mental disorder diseases and systemic diseases are the most important etiology of non-specific dizziness.
IV. Targeted examination is the support for correct diagnosis
Necessary physical examinations should be performed in all patients. Although a complete physical examination cannot be carried out in an outpatient clinic, a targeted examination of vital signs, heart, cerebral nerves, ataxia, deep sensation, and hearing should be performed. Dix-Hallpike examination should be done in all patients with vertigo or with posture-related dizziness.
Vestibular function and pure tone measurements should be targeted in those with possible peripheral vestibular lesions. Neuroimaging should be performed in those with suspected central vestibular lesions, and MRI is particularly recommended over CT because CT is extremely difficult to detect various posterior cranial fossa lesions due to bone interference.
On the contrary, indiscriminate vestibular function or neuroimaging not only cannot help the diagnosis, but can confuse the diagnostic thinking and lead to misdiagnosis. Studies have demonstrated no significant difference in the results of MRI, audiometry, and vestibular function examinations between patients with indiscriminate dizziness and an age-matched normal population, with a positive test rate of less than 1% [8].
The root cause of many clinical misdiagnoses is precisely the over-reliance on ancillary tests without proper consultation, and the lack of adequate understanding of the specificity and limitations of various ancillary tests. For example, Dix-Hallpike examination is not performed in patients with BPPV, but a large number of cervical spine imaging examinations are performed, and then the degenerative changes of the cervical spine common in middle-aged and elderly people are used to explain vertigo, and the diagnosis of cervical spondylosis or cervical vertigo is taken for granted. Then, for example, we do not seriously understand the depression and anxiety status of patients with mental disorder dizziness, but carry out cranial CT, MRI or transcranial Doppler ultrasonography, and then use white matter lesions or lacunar infarcts seen in imaging and common in the elderly population to explain vertigo, or even diagnose it as VBI arbitrarily.
V. Focusing on updated knowledge is the source of correct diagnosis
Although there are many patients with dizziness and vertigo, there are still a considerable number of patients who cannot get the correct diagnosis in time, and some of them will not be diagnosed for a long time. Therefore, on the one hand, clinicians should diagnose the symptoms in a scientific and realistic manner and never make etiological diagnosis arbitrarily, and on the other hand, they should actively study and update their knowledge to improve the diagnosis of dizziness.
In recent years, research on the etiology of dizziness has made great progress, and the related concepts and diagnoses have changed significantly, which deserve the attention of physicians in various departments. As the awareness of BPPV has improved, its diagnosis rate has increased significantly and it has become the first cause of dizziness. For example, in the United Kingdom, the awareness of BPPV was not as good as that in the United States in the 1980s, and the reported incidence rate was 10% lower than that in the United States, but it has been exactly the same since the 1990s. The situation is even more typical in our country. 10 years ago, many doctors did not know about BPPV and few doctors (especially non-otologists) diagnosed the disease, but since neurologists learned to diagnose it [9], many doctors can diagnose hundreds of cases of BPPV. This does not mean that the disease is prevalent in our country, but simply reflects our long-standing lack of awareness of the disease.
Although paroxysmal vertigo in childhood has been found to be associated with migraine in the past, and it has also been found that patients with migraine can present with vertigo rather than headache in old age, and it is called migraine equilibrium, the relationship between vertigo and migraine is not well understood. Recent studies have found that about 30% of dizziness patients have a history of migraine and about 30% of migraine patients have dizziness or vertigo, and the correlation between the two is much greater than the correlation with other diseases or syndromes. The prevalence of motion sickness is nine times higher in migraineurs than in the general population. What used to be called benign episodic vertigo or vestibular Meniere’s disease (without accompanying hearing or neurological symptoms) was also considered to be migraine. As the diagnostic criteria for migrainous vertigo have been promoted, more and more patients are being identified [10, 11].
Some traditional recognition and diagnostic concepts, on the other hand, have been considered wrong or ambiguous due to the progress of etiological research and have been eliminated. For example, China has long diagnosed a large number of middle-aged and elderly people with chronic dizziness or vertigo as VBI and taken for granted that VBI is a state that is not normal but does not meet the criteria of ischemia, but the international classification of ischemic cerebrovascular diseases and the International Classification of Diseases do not have VBI, and our expert consensus [3] also suggests that VBI is a TIA of the posterior circulation system and never a separate and specific disease. We hope that doctors will actively study and eliminate this “garbage can” diagnosis as soon as possible.
Cervical vertigo is used by many physicians, but there is a lack of serious clinical studies on the accuracy of this diagnosis and the reliability of the diagnostic criteria, and many of them use hypothesis instead of clinical evidence or even against the evidence. In fact, there are many causes of dizziness or vertigo caused by turning the neck, and almost all kinds of vertigo disorders can be aggravated by turning the head and neck. Turning the neck can stimulate the carotid body, the carotid and vertebral artery vessels, the myofascia of the neck (responsible for deep sensation in the head and neck), and turning the neck almost invariably causes a head turn in clinical practice, and visual and vestibular sensory stimulation cannot be excluded. The most conservative theories also suggest that vertigo (more often dizziness and instability) during neck rotation is related to abnormalities of deep sensation caused by cervical disorders (myofascial inflammation), and never to the so-called “cervical sympathetic chain stimulation by disc herniation” [12]. Vertigo can be accompanied by neck pain, can be associated with head trauma, whip-like injuries, cervical spine disorders, and in some patients can dramatically improve with physical therapy, but these phenomena do not convince that the mechanism of vertigo is “cervical” and not other possibilities. The current studies on cervical vertigo have weaknesses such as unverifiable diagnosis, lack of specific diagnostic methods, and inability to explain the large number of clinical inconsistencies, so this vague definition and diagnosis is no longer recommended internationally [12].
In conclusion, the correct diagnosis of dizziness or vertigo is mainly based on clinical basis, on the clinician’s correct definition of dizziness symptoms, effective identification of clinical presentation features, correct mastery of different dizziness etiologies, and the multidisciplinary knowledge and experience possessed by the physician, relying on basic clinical skills. Relevant auxiliary tests must be carried out in a targeted manner, and neglecting clinical tests and relying only on auxiliary tests is precisely the root cause of many misdiagnoses.