Original subtitles

The term dizziness can be used to refer to a number of related symptoms like precyncope,

disequilibrium, what's called non-specific dizziness, and vertigo. Asking individuals

specific questions about how they experience dizziness can help clarify the symptom. So let's

go through each of these. Pre-syncope is the prodromal phase that occurs before syncope.

Individuals often complain of seconds to minutes of nearly blacking out or nearly fainting and

feeling light-headed when standing, along with palpations, sweating, a feeling of warmth,

nausea, or even blurry vision. Sometimes there's a history of cardiac disease, such as congestive

heart failure, or coronary artery disease may be present. Pre-syncope could be due to vasovagal

syncope, orthostatic hypotension, or cardiac arrhythmias. So the workup usually includes an

electrocardiogram, or ECG. Dizzequilibrium refers to a sense of imbalance, specifically when

walking, and is usually due to a neurologic disorder like Parkinson's disease, cerebellar

disorders, peripheral neuropathy, or cervical spine disease. This is often described as feeling

the ground moving or feeling like you're on a boat. Nonspecific dizziness is a more vague term that

has a variety of causes ranging from anxiety or panic attacks to hypoglycemia or side effects of

medications like anticholinergics. Finally, there's vertigo, which can be thought of as having

an illusion of self-motion or movement of the surrounding environment. We've all experienced

vertigo. It's that spinny sensation you get after swinging a small child around or the woozy feeling

of seasickness. Yeah, that's vertigo. Vertigo arises when there's a mismatch between other

sensory systems and the vestibular system. The vestibular system is made of the vestibular

apparatus, including the three semicircular canals, the utricle and the saccule, the

vestibular nerve, and the vestibular structures in the brainstem and cerebellum. Vertigo can be

broken down into peripheral vertigo, which is due to damage to the vestibular apparatus or damage to

the vestibular nerve, and central vertigo, which is due to damage to the vestibular structures in

the brainstem or cerebellum. Major causes of peripheral vertigo include benign paroxysmal

positional vertigo, or BPPV, vestibular neuritis, minieres disease, and an acoustic

neuroma. Causes of central vertigo include a posterior circulation stroke, a brainstem

tumor, a migraine, and multiple sclerosis. Now in both types of vertigo, nystagmus, which is a

rhythmic oscillation of the eye, can occur. The nystagmus can be present at rest, or they can be

provoked by the Dick's Hullpike maneuver. But there are subtle nuances in the nystagmus that

differentiate peripheral from central vertigo. In central vertigo, the direction of the

nystagmus can be horizontal, torsional, or rotary, and vertical. In peripheral vertigo,

nystagmus can be horizontal or torsional, but never vertical. Also, in central vertigo, there

is usually no lag time between the Dick's Hullpike maneuver and the onset of nystagmus, and the

nystagmus usually lasts for more than one minute. In peripheral vertigo, there is usually a 2-40

second lag time between the maneuver and the onset of nystagmus, and the nystagmus lasts for less

than one minute. Finally, the Dick's Hullpike maneuver usually provokes mild vertigo in

central vertigo, compared to more severe vertigo in peripheral vertigo. Other associated

symptoms can also provide a clue. For example, the 4Ds, dyplopia, dysphagia, dysarthria, or

dysmetria often suggest central vertigo. Whereas auditory symptoms, like hearing loss or

tinnitus, suggest peripheral vertigo. Okay, so benign positional paroxysmal vertigo, or BPPV,

is by far the most common cause of peripheral vertigo. See, we normally have calcium carbonate

crystals in the utricle and saccule, but the problem arises when they sneak into the

semicircular canals, most commonly the posterior canal. The crystals obstruct the

normal flow of endolymph in the canals when the head moves in a specific direction, like stones

causing turbulence in a smooth river. Without normal endolymphatic flow, the semicircular

canal can't properly detect angular acceleration, causing vertigo. BPPV causes

recurrent episodes of vertigo that are provoked by a specific and predictable change in head

position, such as rolling out of bed. Episodes last less than one minute and are usually

accompanied by nausea or vomiting. Hearing loss and tinnitus are usually absent in BPPV. The

diagnosis is confirmed by exacerbation of vertigo or nystagmus on one side during the

Dicks-Hallpike maneuver. To perform the Dicks-Hallpike maneuver, you have to extend the

neck and turn it to one side while the individual is sitting. Then you have to rapidly place them in a

supine position so that their head hangs over the edge of the bed. After 30 seconds, there might be

nystagmus or vertigo symptoms. If no nystagmus or vertigo symptoms occur, then return the

individual to the upright position and then wait for another 30 seconds. After that, you repeat the

maneuver for the other side as well. The treatment of BPPV is the Epley maneuver, which aims at

guiding the lost crystals back into the utricle where they belong. So let's say an individual has

right-sided BPPV based on the Dicks-Hallpike maneuver. With the individual upright, grasp

their head on both sides and rapidly position them to the supine position with the right ear pointing

downwards. Then immediately rotate the head to the left side so that the right ear points upwards.

Hold this position for 30 seconds. Next, ask the individual to turn their body to the left side and

then rotate their head until their nose is pointing towards the floor. Hold this position

for 30 seconds, then rapidly lift the individual back to the upright position. Works like magic.

Because BPPV can reoccur, individuals are taught a modified version of the Epley maneuver that they

can do themselves. First, in the sitting position, the individual should turn their head

about 45 degrees to the affected side, let's say the right side. Then lie down supine and wait for 30

seconds. Then without raising the head, turn it 90 degrees to the left and wait for another 30

seconds. Next, turn the body 90 degrees to the left and wait another 30 seconds. Finally, sit up on the

left side. The modified Epley maneuver should be performed three times a day until the individual

has no symptoms for at least 24 hours. Vestibular neuritis, or labyrinthitis, is inflammation of

the vestibular portion of the 8th cranial nerve. In comparison with BPPV, vestibular neuritis

causes acute, severe, constant peripheral vertigo lasting several days. Head movement can

worsen the symptoms, but the symptoms can occur at rest and don't rely on a specific position. Also,

unlike BPPV, there may be hearing loss. Individuals with vestibular neuritis sometimes

have a prior viral upper respiratory tract infection. The diagnosis is based on the

symptoms, and although there's conflicting evidence, corticosteroids can be given to help

the inflammation. Alright, now, Meniere's disease is also called endo-emphatic hydrops,

and it's due to having excess endo-emphatic fluid in the semicircular canals. Meniere's disease

tends to occur in people over the age of 65 who develop a classic triad of symptoms. Recurrent

episodic vertigo, hearing loss, and tinnitus. Audio call, transcript. Audio call, transcript.

Audio call, transcript. Audio call, transcript. A HINTS exam is an acronym for three physical

examination maneuvers. Head impulse testing, nystagmus, and the test of skew. In the first 24 to

48 hours of isolated vertigo, when performed by an expert, the HINTS exam is better than the MRI in

ruling out posterior circulation stroke. Now, to do a head impulse test, you sit opposite a person

and ask them to fix their gaze on your nose. Next, you passively turn their head to one side.

Normally, the vestibuloocular reflex rapidly corrects the eyes back to the center so that their

eyes remain fixed on your nose. An abnormal head impulse test is when that doesn't happen, and

there's a lag time until their eyes are able to remain fixed on your nose. So an abnormal or

positive test indicates a peripheral cause of vertigo, while a normal or negative test

indicates a more concerning central cause, like stroke. It's one of the few times in medicine where

an abnormal test is the less concerning outcome. Next is nystagmus, which has two phases, a fast

phase and a slow phase. The fast phase is when the eyes move quickly in one direction, and the slow

phase is when the eyes swing back slowly in the other direction. When we talk about the direction

of nystagmus, we're referring to the fast phase. In peripheral vertigo, the fast phase is usually

directed to one side only, for example, the right side only. A nystagmus in which the fast phase

alternates in direction is concerning for a posterior circulation stroke. Finally, the test

of skew involves asking the individual to look at their nose while covering one eye. If the covered

eye deviates away from its original position and then corrects back when it's uncovered, that

suggests a central cause. If any one out of the three parts of the hands exam indicates a central

cause, then a brain MRI should be done to look for a posterior circulation stroke. Alright, now

multiple sclerosis is a central nervous system demyelinating disease that can cause central

vertigo. Individuals typically have a variety of neurological symptoms that localize to

different parts of the brain and occur at different points in time. Treatment of multiple

sclerosis includes disease modifying agents such as interferon beta and corticosteroids for

acute attacks. Another cause is a brainstem tumor such as a pylocytic astrocytoma which can

encroach on the vestibular structures in the brainstem causing vertigo. Treatment depends on

the type of tumor. It may include surgical resection as well as chemo or radiotherapy. Also,

a rare type of migraine called a vertebro-basilar migraine can present with vertigo following the

migraine headache. Unfortunately, the usual migraine abortive medications like tryptins and

ergotomies do not relieve the vertigo in these individuals. Therefore, it's best to avoid

triggers such as stress and smoking and provide prophylactic treatment with medications like

rapamil. Finally, there are some medications like aminoglycosides, anticonvulsants like

vanidawin and the antimalarial quinine that are toxic to the vestibular system. These

medications usually affect both the right and left vestibular symptoms roughly equally. They

balance each other out so individuals rarely experience vertigo. Instead, the vestibular

ocular reflex is impaired in the individual's experience ocelopsia, which is an illusion of a

moving environment when the individual looks in any direction. As a result, there's an abnormal

head impulse test in these individuals. Alright, now symptoms of vertigo, regardless of the cause,

can be treated with anihistamines such as mycocline and diphenhydramine, antiemetics

such as ondanzotron or metaclopramide, and benzodiazepines such as diazepam. These

medications should be given for a short duration and stopped once the symptoms are relieved

because they can interfere with the long-term recovery of the vestibular system. Alright, this

is a quick recap. Dizziness is a common complaint that uses four different entities. Pre-syncope,

disequilibrium, nonspecific dizziness, and vertigo. Pre-syncope may indicate a cardiac

cause like arrhythmias, while disequilibrium usually indicates a neurological issue like

migraines. Psychiatric disorders like depression and anxiety may cause a nonspecific

dizziness. Vertigo is defined as an illusion of movement, whether that's self-movement or

movement of the surrounding environment. Vertigo is classified into peripheral and

central vertigo, which can be differentiated based on the features of nystagmus on a physical

exam. In central vertigo, the nystagmus can be horizontal, torsional, or vertical, and there's

usually no lag time between performing the dicks-hull pike maneuver and the onset of

nystagmus, and the nystagmus lasts more than a minute. In contrast, the nystagmus in peripheral

vertigo can be horizontal or torsional, but never vertical. There's usually a lag time ranging from

2 to 40 seconds, and the nystagmus usually lasts for less than a minute. Auditory symptoms like

tinnitus or hearing loss suggest a peripheral cause, while a neurological symptom like

hemiparesis, numbness, dyplopia, dysphagia, dysarthria, and dysmetria suggest a central

cause. Pre-referral causes include benign paroxysmal positional vertigo, vestibular

neuritis, maniaeus disease, or acoustic neuroma. Central causes include a posterior

circulation stroke, multiple sclerosis, migraine, or a brainstem tumor. Certain

medications like immunoglycosides can be toxic to the vestibular system, but because they affect

both vestibular systems equally, they don't cause vertigo. Instead, they cause oscilopsia,

an illusion of environmental movement whenever the individual moves their eyes. In an individual

presenting with acute vertigo, with other neurological symptoms, an MRI is warranted to

look for a posterior circulation stroke, whereas individuals with acute isolated vertigo should

have a HINDS exam, the head impulse, nystagmus, and test of skew. If one of the three tests indicate

a central cause, then an MRI should be done to look for a posterior circulation stroke. Thank you.