Norina Usman, M.B.B.S[4]

Dizziness is a symptom rather than a condition on its own. It is a complex and subjective complaint that encompasses a wide spectrum of symptomatology. It is a sensation of postural unsteadiness or deceptive motion. It is one of the most communal presenting complaints that accounts for 5% of primary care practice for individuals aged 65 or older. Dizziness is a nonspecific term mainly used by many people and is classified into different categories: vertigo, spinning, disequilibrium, giddiness, presyncope, faintness, lightheadedness, or feeling woozy. It is one of the most common presenting symptom among patients seen by emergency medical physicians, primary care physicians, neurologists, and otolaryngologists.

Dizziness may be classified based on the symptoms of the patient into 4 main subtypes including vertigo, presyncope, [[BPPV], and disequilibrium.

It is understood that pathophysiology of dizziness depends on the etiological subtype including orthostatic hypotension, benign paroxysmal positional vertigo, Menier’s disease, Parkinson’s disease, hyperventilation syndrome, peripheral neuropathy, and vestibular migraine.

Dizziness may be caused by hypotension, dehydration, arrhythmia, labyrinthitis, Meniere’s disease, stroke, or hypoglycemia. Other causes are based on the organ system such as cardiovascular, neurological, musculoskeletal, dermatological, endocrine, infectious, pulmonological or side effects of the medicine.

Dizziness must be differentiated from other diseases that cause vertigo, nystagmus, and hearing problems, such as vestibular neuritis, HSV oticus, Meniere disease, labyrinrhine concussion, perilymphatic fistula, semicircular canal dehiscence syndrome, vestibular paroxysmia, Cogan syndrome, vestibular schwannoma, otitis media, aminoglycoside toxicity, recurrent vestibulopathy, vestibular migraine, epileptic vertigo, multiple sclerosis, brain tumors, cerebellar infarction/hemorrhage, brain stem ischemia, [[Arnold-Chiari malformation|chiari malformation], presyncope and disequilibrium.

Dizziness is one of the most common complaints in ambulatory care, accounting for nearly 8 million outpatient visits annually in the United States. The incidence of dizziness is approximately 50–100 million worldwide, and around 4.3 million patients in the United States. The lifetime prevalence of dizziness is expected to be 30%. Idiopathic dizziness commonly affects individuals 25 years and older in an emergency department.

Common risk factors in the development of dizziness include family history of thromboembolic factors (diabetes, hypertension, high cholesterol, and rheumatic disease), cardiac arrhythmias, stroke, medication side effect (diuretics, antiepileptic drugs, opioid-based analgesics, antipsychotic drugs, antidepressants, antihypertensive, antifungal, lithium, benzodiazepines, antiarrhythmic, antimalarial and anti-HIV-drugs). Multiple sclerosis, seizures, brain tumors, benign positional vertigo, and labyrinthitis.

If left untreated, patients may experience spontaneous recovery. Common complications of dizziness include nausea, vomiting, fainting, fall, imbalance and hearing loss, and neurological complications following Dix Hallpike or Epley maneuvers. Prognosis is generally good, and the 10-year mortality rate of patients with dizziness is low approximately (hazard ratio [HR] = 0.62; 95% CI, 0.40-0.96)

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Based on the symptoms, dizziness may be classified into vertigo, presyncope, disequilibrium, lightheadedness. Vertigo can further be classified into timing and trigger as well as based on the area of pathology such as central and/ or peripheral.

Dizziness may be classified into subtypes based on the symptoms^[1]:

One way to classify dizziness and vertigo is based on the timing and trigger as follows:^[3]

• New episodic:
  • With triggers:
    • Triggered episodic vestibular syndrome (e.g., positional vertigo from BPPV)
  • Without triggers:
    • Spontaneous episodic vestibular syndrome (e.g., arrhythmia from cardiac causes)

-New continuous:
  - Post-exposure acute vestibular syndrome (e.g., after gentamicin)
  - Spontaneous acute vestibular syndrome (e.g., stroke of posterior fossa)

-Chronic, persistent:
  - Chronic vestibular syndrome (unilateral vestibular loss, present with head movement)
  - Spontaneous chronic vestibular syndrome (associated with degeneration of cerebellum)

Vertigo can be further classified into peripheral and central based on the area of pathology (explained further under the pathophysiology section): ^[4][5]

-Central:
  -Ischemia or infarction of the brainstem
  -Vertebrobasilar insuffiency
  -Demyelination syndromes like multiple sclerosis
  -Space occupying lesions (both benign and malignant)
  -Arnold-Chiari malformation
  -Vestibular migraine

-Peripheral:
  -Benign Paroxysmal Positional Vertigo (BPPV)
  -Cogan syndrome (autoimmune condition that affects eyes and inner ears)
  -Acoustic neuroma
  -Herpes zoster
  -Labyrynthitis
  -Vestibular neuritis
  -Medication toxicity (e.g., aminoglycosides, etc)
  -Perilymphatic fistula

The pathophysiology of dizziness depends on the etiological subtype including orthostatic hypotension, benign paroxysmal positional vertigo, Meniere’s disease, Parkinson’s disease, hyperventilation syndrome, peripheral neuropathy, and vestibular migraine.

The pathophysiology of dizziness depends on the etiological subtype, and area of pathology involved^{[1][2][3][4][5]}.

The pathophysiology of dizziness can be explained according to one of its classification systems based on central and peripheral, although there is often overlap between the two. ^{[6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16]}

-Peripheral:

-Vestibular dysfunction which involves vestibular neuritis/neuronitis can occur as a single attack or multiple attacks. When there is concurrent hearing loss, it is termed at neurolabyrinthitis. The hair cell bodies are said to be involved that help in transducing movement.

-Bilateral vestibular hypofunction (partial or complete): usually by toxic (gentamicin) or immune mechanisms.

-Autoimmune: rapidly progressive and bilateral. Like any other autoimmune disease, there is a female preponderance in the reproductive age group.

-Systemic or central vestibular dysfunction: involves the vestibular nuclei.

-Meniere’s disease which is the tetrad of vertigo, tinnitus, sensorineural hearing loss and aural fullness. The exact etiology is unknown although viral causes have been implicated. The symptoms arise because of endolymphatic pressure change.

-BPPV: The posterior semicircular canal is the most commonly involved space. The most likely etiology is dislodgment of an otoconia.

-Perilymphatic fistula: Fistula is an abnormal communication between two structures; in this case between the membranous labyrinth and middle ear. Can be due to causes like barotrauma (implosive) or increased intracranial pressure (explosive). Acquired fistulas may result from chronic ear surgery.

-Central causes can be further divided based on issues with circulation and other miscellaneous causes as follows

-Circulation related causes:

-Cardiogenic, such as: infarction, occlusion. Conditions that compromise blood supply to the brain for example; cardiac failure, aortic stenosis, arrhythmia, etc can causes dizziness. -Occlusion of the carotid artery: usually not a cause for dizziness unless both anterior and posterior circulations are compromised. -Cerebrovascular accidents which involve both large and small vessel ischemia or stroke. -Large vessel syndromes: -Veretebrobasilar insufficiency -Vertebral artery thrombosis -Basilar artery thrombosis -Small vessel syndromes: -Wallenberg(Lateral medullary) syndrome: accompanying features are Horner’s syndrome, dysarthria, hemiataxia -Anterior inferior cerebellar artery syndrome- labyrinthine artery ischemia causing unilateral deafness, ataxia and facial weakness -Labyrythnine artery syndrome -Other causes:

-Acoustic neuroma: benign tumor of the eighth cranial nerve causing hearing loss that is high frequency and sensorineural. Unilateral tinnitus, dizziness is seen in <20% of the population, upto 70% may have imbalance. -Cervicogenic -Metabolic dizziness: comprising of low blood sugar (hypoglycemia) and accompanied by other symptoms such as tremors, palpitations, sweating, etc. Thyroid conditions (both hypothyroidism and hyperthyroidism) as well as low blood magnesium levels can also cause dizziness. -Migraine- Neuhauser and his colleagues formed the following list of criteria for migrainous vertigo: -recurrent attacks of vertigo -headache meeting criteria of International Headache Society -At least one of the following symptoms during at least two of these attacks: migraine headache, intolerance to light, intolerance to sound, presence of an aura, absence of other causes -Pathophysiologic- integration of the visual, vestibular, autonomic, and proprioceptive systems. Not necessarily pathologic, example: feeling of falling while standing on the ledge of a building that is very tall. -Anxiety and related disorders: may or may not be related to hyperventilation. Possible exacerbation by a vestibular syndrome. Phobic dizziness/ postural vertigo is the fear of falling without gait instability. Usually associated with panic disorder or agoraphobia. -Vestibular epilepsy: episode of dizziness or vertigo accompanied by a seizure or preceding the aura.

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Dizziness may be caused by hypotension, dehydration, arrhythmia, labyrinthitis, Meniere’s disease, stroke, or hypoglycemia. Other causes are based on the organ system such as cardiovascular, neurological, musculoskeletal, dermatological, endocrine, infectious, pulmonological or side effects of the medicine.

Common causes of dizziness may include^{[1][2][3][4][5][6][7]}:

• Hypotension
• Dehydration
• Hypoglycemia
• Arrhythmias
• Stroke
• Labyrinthitis
• Meniere’s disease

Dizziness causes developed by WikiDoc.org

Dizziness causes developed by WikiDoc.org

Dizziness causes developed by WikiDoc.org

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Dizziness is a common but vague symptom. A wide variety of symptoms are often referred to as dizziness, these symptoms include vertigo, presyncope and disequilibrium. Dizziness should also be differentiated from psychogenic dizziness.

Dizziness must be differentiated from vertigo, presyncope, and disequilibrium^{[1][2][3][4][5]}.

• Psychogenic dizziness is not a true dizziness. It is associated with psychiatric symptoms that precede its onset. It occurs in anxious or phobic individuals and do not include any specific symptoms and it can be replicated by hyperventilation^[7][8].
• Synonyms used to describe psychogenic dizziness include:
  • Functional dizziness
  • Hyperventilation syndrome
  • Nonspecific dizziness
  • Phobic postural vertigo
  • Psychiatric dizziness
  • Psychic dizziness
  • Psychophysiologic dizziness
  • Somatization

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Dizziness is the most common non-pain symptom following fatigue in clinic and community populations.It is also one of the most common complaints in ambulatory care, accounting for nearly 8 million outpatient visits annually in the United States.^[1][2].

Annually, the incidence of dizziness is estimated to be 50–100 million worldwide, and around 4.3 million patients in the United States. The lifetime prevalence of dizziness is expected to be 30%^[3][4].

The incidence of dizziness increases with age; is most commonly seen in individuals 25 years and older in an emergency department^[5][6].

There is no racial predilection to dizziness.

Common risk factors in the development of dizziness include family history of thromboembolic factors (diabetes, hypertension, high cholesterol, and rheumatic disease), cardiac arrhythmias, stroke, medication side effect (diuretics, antiepileptic drugs, opioid-based analgesics, antipsychotic drugs, antidepressants, antihypertensive, antifungal, lithium, benzodiazepines, antiarrhythmic, antimalarial and anti-HIV-drugs). Multiple sclerosis, seizures, brain tumors, benign positional vertigo and labyrinthitis.

Common risk factors in the development of dizziness include^[1][2][3]:

• Family history of thromboembolic factors (diabetes, hypertension, high cholesterol, and rheumatic disease)
• Cardiac arrhythmias
• Stroke
• Medication side effect (diuretics, antiepileptic drugs, opioid-based analgesics, antipsychotic drugs, antidepressants, antihypertensive, antifungal, lithium, benzodiazepines, antiarrhythmic, antimalarial and anti-HIV-drugs.
• Multiple sclerosis
• Seizures
• Brain tumors
• Benign positional vertigo
• Labyrinthitis

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There is insufficient evidence to recommend routine screening for [disease/malignancy].

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• [Condition 1]
• [Condition 2]
• [Condition 3]

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If left untreated, patients may experience spontaneous recovery. Common complications of dizziness include nausea, vomiting, fainting, fall, imbalance and hearing loss and neurological complications following Dix Hallpike or Epley maneuvers. Prognosis is generally good, and the 10-year mortality rate of patients with dizziness is low approximately (hazard ratio [HR] = 0.62; 95% CI, 0.40-0.96)^[1].

The symptoms of dizziness typically develop gradually over years and may have a history of cardiovascular disease (for e.g; arrhythmia, myocardial infarction, ischemic heart disease, and neurological disorders such as Parkinson’s disease, migraine, stroke, and epilepsy^[2].

Common complications of dizziness include:

• Fall
• Imbalance
• Hearing loss

Depending on the extent of the disease progression at the time of diagnosis, the prognosis may vary. However, the prognosis is generally regarded as good.

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