Vertigo overview

# Overview
Vertigo is identified as 'room spinning around'. It is a type of dizziness. Presyncope, lightheadedness and disequilibrium are other types of dizziness and should be ruled out. The cause of vertigo can be peripheral or central in origin. In peripheral vertigo, dysfunction is in the vestibular system 
which includes the vestibule (utricle and saccule), semicircular canals, and the vestibular nerve. Central etiologies of vertigo usually originates from the brainstem or cerebellum. Most common causes of vertigo to appear in primary-care are benign paroxysmal positional vertigo, acute vestibular neuronitis, and Menieres disease. Best approach to diagnose vertigo etiology is to obtain a complete history paired with a focal examination including assessment of cranial nerves, nystagmus, sensorineural hearing loss (Rinne or Webers test), otoscopic exam of ear canal and tympanic membrane, HINTS (cover/uncover test), Dix-Hallpike maneuver and/or Henneberts sign. Acute/severe attacks of vertigo may subside in a day or two after brainstem compensation. Supportive therapy includes bed rest, antihistamine, antiemetic (prochlorperazine, metoclopramide) to relief the symptom. These drugs should not be used for a long period of time as it may delay the compensatory mechanism in the brainstem and result in the prolongation of vertigo symptom.Treating the underlying cause is the definitive treatment of vertigo.

# Historical Perspective
Vertigo is derived from the Latin words vertigin and vertere which means  "a whirling or spinning movement," and "to turn", respectively.

# Classification
Vertigo is typically classified into one of two categories depending on the location of the damaged vestibular pathway. These are peripheral or central vertigo. Each category has a distinct set of characteristics and associated findings. Vertigo can also occur after long flights or boat journeys where the mind gets used to turbulence, resulting in a person feeling as if they are moving up and down. This usually subsides after a few days.

# Pathophysiology
Disruption in the vestibular system results in vertigo. The region of disruption could be peripheral (labyrinth, vestibular nerve) or central (brainstem, cerebellum). Vestibulo-ocular reflex is responsible for stabilizing gaze during head movement, it is controlled by six neurotransmitters, which are glutamate, acetylcholine, GABA, dopamine, histamine and norepinephrine.

# Causes
Common causes of vertigo are Menieres disease, benign paroxysmal positional vertigo, labyrinthitis, vestibular neuritis. Life-threatening causes include brainstem ischemia/hemorrhage, hypertension crisis, drug overdose, cyanide poisoning.

# Differentiating Vertigo from other Diseases
Vertigo is one of the four type of dizziness, therefore it must be differentiated from other forms of dizziness, presyncope, lightheadedness and disequilibrium.

# Epidemiology and Demographics
Among the patient who presents with dizziness in the primary care setting, fifty-four percent have vertigo upon investigation. Benign paroxysmal positional vertigo, acute vestibular neuronitis, and Menieres disease account for ninety-three percent of patients diagnosed with true vertigo in a primary care setting.

# Risk Factors
There are no established risk factors for vertigo, as it is a symptom of an underlying disease. However, vertigo can be prevented in some cases by controlling risk factors for the underlying cause.

# Screening
There is insufficient evidence to recommend routine screening for vertigo.

# Diagnostic Study of Choice
There are no established criteria for the diagnosis of vertigo. The best approach to diagnose vertigo etiology is to obtain a complete history paired with a focal examination.

# History and Symptoms
It is important to differentiate between other causes of dizziness before evaluating the cause of vertigo. True vertigo is described as the room spinning around the patient. Once true vertigo is established next step is to identify if the origin of dysfunction is central or peripheral. Detailed investigation of the time course of vertigo and associated signs and symptoms aid in identifying the cause of vertigo.

# Physical Examination
Physical examination of patients experiencing vertigo should include assessment of cranial nerves, nystagmus, sensorineural hearing loss (Rinne or Webers test), otoscopic exam of the ear canal and tympanic membrane, HINTS (cover/uncover test), Dix-Hallpike maneuver, and/or Henneberts sign.

# Laboratory Findings
There are no diagnostic laboratory findings associated with vertigo.

# Electrocardiogram
There are no ECG findings associated with vertigo. However, an ECG should be ordered to look for cardiac causes of dizziness including bradycardia, orthostatic hypotension resulting in poor circulation, privided true vertigo is not established as the cause od dizziness in the patient

# X-ray
An x-ray of the cervical spine may be helpful in the diagnosis of peripheral vertigo of unknown origin. Findings on an x-ray include, extended cervical spine posture, degenerative changes in the cervical spine can cause peripheral vertigo, and/or uncovertebral arthroses.

# Echocardiography or Ultrasound
There are no echocardiography/ultrasound findings associated with vertigo. However, an echocardiography/ultrasound may be helpful in the diagnosis of underlying etiology of vertigo or to rule out cardiac cause of dizziness if true vertigo is not established. Use of echo-color Doppler ultrasound is helpful to look for plaque in extracranial vessels supplying blood to brain in patients with peripheral vertigo but exact cause still unidentified.

# CT scan
CT scan is not the first-line imaging method preferred to determine the underlying cause of central vertigo due to its low sensitivity in identifying ischemic stroke and a negative CT scan cannot completely rule out the central cause of vertigo, it still needs to be further investigated with the help of an MRI.

# MRI
An MRI is the first-line imaging if the cause of vertigo is suspected to be central in origin. MRI is superior to a CT scan due to its ability to visualize the posterior fossa.

# Other Imaging Findings
There are no other imaging findings associated with vertigo. However, some underlying cause may benefit from electronystagmography or electroencephalogram. Further imaging should be conducted according to the diagnostic requirements of the etiology behind the symptom of vertigo.

# Other Diagnostic Studies
There are no other diagnostic studies associated with vertigo. However, the causes of vertigo should be evaluated further according to its diagnostic protocol.

# Medical Therapy
Acute/severe attacks of vertigo may subside in a day or two after brainstem compensation. Supportive therapy includes bed rest, antihistamine, antiemetic (prochlorperazine, metoclopramide) to relief the symptom. Antihistamine (meclizine,betahistine,dimenhydrinate), antiemetic, anticholinergic (scopolamine) and benzodiazepines (diazepam,lorazepam) are the common medications used to treat vertigo as a symptom. These drugs should not be used for a long period of time as it may delay the compensatory mechanism in the brainstem and result in the prolongation of vertigo symptom. Some patients may be a candidate for vestibular rehabilitation. Treating the underlying cause is the definitive treatment of vertigo.

# Surgery
For the majority of underlying causes of vertigo, the mainstay of treatment is medical therapy. Surgery is usually reserved for patients with either tumor-associated vertigo, cholesteatoma, and/or when it does not respond to multiple medical therapies.

# Primary Prevention
There are no established measures for the primary prevention of vertigo, as it occurs as a symptom of underlying pathology. In some diseases controlling risk factors or triggering, factors can prevent the disease hence preventing the symptoms.

# Secondary Prevention
Effective measures for the secondary prevention of vertigo include optimal treatment of the underlying etiology.