Dizziness

Dizziness is an imprecise term used to describe various symptoms, each of which has a different pathophysiologic mechanism and significance (Table 1). If the patient cannot describe the symptoms, ask the patient if the problem primarily causes problems in the head or problems with balance. If the patient has spells, have the patient describe in detail the initial spell and the last severe spell.

» Hallucination of rotation of self or the surroundings in a horizontal or vertical direction, usually described as spinning, which suggests vestibular dysfunction. » Presentation: ˃ Usually episodic ˃ with an abrupt onset ˃ often associated with nausea or vomiting.
» Dysfunction can be located in the PNS or CNS » Prevalence:  (Serre, 1985) 25/10/2014 » Impending faint or loss of consciousness, not associated with an illusion of movement.
˃ May begin with diminished vision or a roaring sensation in the ears » This subtype of dizziness results from conditions that compromise the brain's supply of -  (Hain T, 2003) 25/10/2014 13 Dr Rudi Gerhardt (Hain T, 2003) 25/10/2014 14 Dr Rudi Gerhardt (Hain T, 2003) 25/10/2014 » The vestibular apparatus consists of: » Otolithic membrane: a gelatinous sheet with calcium carbonate particles, the otoconia, lying on its surface or embedded in its top layer.
» Functions: Detect the position of the head and the movements of the head relative to gravity.
» As the head moves, the pull of gravity on the otolithic membrane causes it to lag behind.
» Otolithic membrane shifts with respect to the underlying hair cells, the stereocilia of the hair cells are deflected.
» Depending on the direction of the deflection the cells will be either depolarized or hyperpolarized, resulting in an increase or decrease in the generation of action potentials. ˃ Expanded end at each canal containing ˃ Crista ampullaris a cone-shaped structure, covered in "hair cells" » Cupula: gel-like structure covering the hair cells » Because the gel of the cupula does not contain otoconia, it does not respond to gravity. » As the head moves, inertia causes the endolymph within the canals to lag behind and push on the cupula. » As a result, the stereocilia of the ampullary hair cells bend, and the electrical properties of the hair cells change » Working together, the hair cells send signals to the brain encoding head movement in all 3 planes.  (Hain T, 2003)  » Input predominantly from the semicircular canals but also from the otolith organs projects to the superior and medial nuclei, which send signals in the contralateral ascending MLF to coordinate head and eye movements via cranial nerve nuclei III, IV, and VI.
» The medial nucleus also forms a substantial bilateral projection caudally to the cervical spinal cord via the descending MLF to coordinate postural head and neck movements.
» Input predominantly from the otolith organs but also from the semicircular canals projects to the lateral nucleus, which projects ipsilaterally to the spinal cord mostly in the lateral vestibulospinal tract to coordinate postural responses to gravity.
» Inferior nucleus which projects bilaterally to the cervical spinal cord by the descending MLF and to the vestibular parts of the cerebellum and the other vestibular nuclei.
» All vestibular nuclei send a small number of axons via the thalamus to the somatosensory cortex: For conscious appreciation of balance and head position. » Sensation of impending faint or loss of consciousness that is not associated with an illusion of movement. » Results from conditions that compromise the brain's supply of blood, oxygen, glucose; which affects the function of the cerebral hemispheres or brainstem. » Symptoms typically arise from vascular, autonomic or cardiac causes. » Cardiac disease: Arrhythmia, outflow obstruction or low cardiac output states » Autonomic failure typically results in postural or orthostatic hypotension.
˃ This may occur as part of neurologic conditions such as polyneuropathy (e.g. diabetic neuropathy) or certain disorders of the CNS (Parkinson disease).
» Many medications can also exacerbate or bring on postural hypotension. » Vasovagal episodes are common and may show inappropriately slow heart rates at the time of the attacks, along with hypotension. » Anxiety states with hyperventilation can cause presyncope.
˃ Hyperventilation results in cerebral vasoconstriction due to the loss of CO 2 and the attendant change in blood pH.
» Migraine can also produce presyncope (cerebrovascular instability?)  (Hain T, 2003) 25/10/2014 » Feeling of being unsteady on one's feet. » Improves when there are other sensory cues (such as the ability to touch things) » Worse, when the patient's vision is blocked, walking on uneven surface. » Useful questions: ˃ "Does it only happen when you're on your feet"? ˃ "Does it get much better if you touch things"? ˃ "Is the sensation worse in the dark"?
Dr Rudi Gerhardt 36 25/10/2014 » Due to disturbance of sensory or motor control systems that are necessary to maintain the upright posture. » The most common cause, by far, is multisensory deficit. » Gradual decrease in sensory acuity in several systems: ˃ diminished sensitivity to joint position (proprioception) in the feet ˃ decreased sensitivity of the vestibular system ˃ decreasing visual acuity » Many of these patients have polyneuropathy that is damaging peripheral nerves » Typically, these patients improve with a cane or other gait assistive device. » Patients with Parkinson's or cerebellar disease often have disequilibrium due to motor difficulties. » Slowed responses in Parkinson's disease or incoordination and cerebellar disease may make the patient entirely unable to walk safely. » The patient perceives this as disequilibrium. » Therefore, the evaluation of the patient with disequilibrium requires both testing of sensation and testing of motor function, including strength, tone and coordination.  (Serre, 1985) 25/10/2014 » Described as a vague or floating sensation » Patient having difficulty describing the sensations. » May be associated with anxiety and depression. » Psychiatric disorders are considered the primary cause of this subtype of dizziness accounting for ~ 10 -25% of all dizziness cases. » In older adults, anxiety, depression, and adjustment reactions were factors contributing to dizziness. » Not classified under vertigo: ˃ As the symptom is tilting of the environment and not spinning » Tilting of the environment tends to challenge the diagnostic classification system. » Ischaemia or infarction in the vertebrobasilar system and its branches unilaterally affecting the vestibular nuclei, the MLF, other nuclei involved in the vestibular mechanism, or the thalamus can also result in a patient reporting a subjective tilt of the visual vertical axis in a frontal plane.  » Cerebellar or brain stem disease can cause saccadic eye tracking in which the patient repeatedly loses the target and then catches up with a small saccade.
Dr Rudi Gerhardt 74 25/10/2014 » Action: Turn the P's head 45º degrees to one side while seated and rapidly but carefully have the patient recline. » Observe eyes for nystagmus, if present, note the following 5 characteristics:

» Interpretation:
˃ There is no such thing as a "vestibular gait." ˃ Acute unilateral loss of otolithic function: P will tend to veer toward the side of the lesion. ˃ Brain stem and musculoskeletal lesions: also produce lateral deviation during ambulation. » 2 ways to make this test more sensitive to vestibular deficits:  1. Start at side of + Dix-Hallpike Test 2. P is held in the right head hanging position for 20-30 sec. or until nystagmus exhausts 3. Head is turned 90º toward the unaffected side, and is held for 20-30 sec. or until nystagmus exhausts 4. P is rolled onto unaffected side, turned another 90º so the head is nearly in the face-down position. Position is held for 20-30 sec. or until nystagmus exhausts. 5. P is brought to the sitting position.
˃ Semont maneuver is possibly more effective than no treatment, or sham treatment, or Brandt-Daroff exercises as treatment for posterior canal BPPV » Are postmaneuver activity restrictions necessary after canalith repositioning procedure?
˃ There seems to be little difference in the rate of treatment success whether or not restrictions were included.

» What is the efficacy of Brandt-Daroff exercises, habituation exercises, or patient selfadministered treatments for BPPV?
˃ Patients treated with Brandt-Daroff exercises, "habituation exercises," did no better than those treated with a sham procedure.
Dr Rudi Gerhardt 95 25/10/2014 (Fife TD et al, 2008) (Hain TC 2013). » Anterior canal BPPV is usually transitory and most often is the result of "canal switch" that occurs in the course of treating other more common forms of BPPV. » We identified only two studies specifically addressing the treatment of anterior canal BPPV; both were Class IV studies. » Success rates were between 92% and 97%, though there were no controls to determine whether this represents an improvement over the natural history of this frequently selfresolving form of BPPV (Five et al 2008).
Dr Rudi Gerhardt 10 7 25/10/2014 » Is a condition in which debris is stuck to the cupula of a semicircular canal, rather than being loose within the canal. » Cupulolithiasis should result in a constant nystagmus. » This pattern is sometimes seen (Smouha et al. 1995). » Cupulolithiasis might theoretically occur in any canalhorizontal, anterior or vertical, each of which might have it's own pattern of positional nystagmus. » If cupulolithiasis of the posterior canal is suspected, it seems logical to treat with the Epley maneuver. » Other maneuvers have been proposed for lateral canal cupulolithiasis. » There are no controlled studies of cupulolithiasis to indicate which strategy is the most effective.
Dr Rudi Gerhardt 10 8 25/10/2014 » Is a hypothetical condition in which debris is present on the vestibule-side of the cupula, rather than being on the canal side. » For this theory, there is loose debris, close to but unattached to the cupula of the posterior canal, possibly in the vestibule or short arm of the semicircular canal. » This mechanism would be expected to resemble cupulolithiasis, having a persistent nystagmus, but with intermittency because the debris is movable. » Very little data is available as to the frequency of this pattern, and no data is available regarding treatment.
Dr Rudi Gerhardt 10 9 25/10/2014 » If debris can get into one canal, why shouldn't it be able to get into more than one? » It is common to find small amounts of horizontal nystagmus or contralateral downbeating nystagmus in a person with classic posterior canal BPPV. » While other explanations are possible, the most likely one is that there is debris in multiple canals. » Gradually a literature is developing about these situations (Bertholon et al, 2005). » Episodes last for several hours to a day » Vertigo-free periods lasting for weeks or months. » Following a severe attack, most people find that they are exhausted and must sleep for several hours. » There is a large amount of variability in the duration of symptoms. » Hearing loss is progressive » Vertigo attacks appear to "burn out" over time. » Some patients have sudden "drop" attacks without loss of consciousness.  (Hain T, 2003) (Hain T, 2003) » Idiopathic endolymphatic hydrops: Distention from either overproduction or retention of endolymph appears to be the cause in most cases. » The area of the ear affected is the entire labyrinth, which includes both the semicircular canals and the cochlea. » Specifically, there appears to be a problem with the endolymphatic sac's (immune processing area) and/or duct's filtration and excretion function with a possible autoimmune etiology. » An association between high levels of ADH and stress has been found in Meniere's patients. » Head trauma or previous infection may be factors. » Pregnant females may be more prone. » Meniere's disease is the 4 th most common cause of vertigo. » The primary conservative approach is based on the theory that increased fluid causes distention and symptoms. » Therefore, diuretic therapy (herbal or prescribed) in combination with a salt-restriction diet appears to be effective in managing the vertiginous component of Meniere's disease in ~ ⅔ of patients. » For a few patients, surgical intervention using decompression of the endolymphatic sac appears effective. » Other approaches include transtympanic gentamicin and, for intractable cases, vestibular nerve section. » Although, in one study, half of patients had residual subjective complaints, 85% were satisfied with their decision. » The possibility of an overlap between Meniere's disease and cervicogenic vertigo warrants a treatment trial of cervical manipulation in patients with Meniere's disease.  ˃ Symptoms are often only precipitated by sudden movements. ˃ A sudden turn of the head is the most common 'problem' motion. » While patients with these disorders can be sensitive to head position, it is generally not related to the side of the head which is down, but rather just whether the patient is lying down or sitting up. » If there are hearing symptoms with dizziness, then labyrinthitis would be the first consideration.
» Vestibular neuronitis: another term used for the same clinical syndrome. » "Neuritis" implies damage to the nerve » "Neuronitis' implies damage to the sensory neurons of the vestibular ganglion.
» There is actually evidence for both. » There is also some evidence for viral damage to the brainstem vestibular nucleus (Arbusow et al, 2000), a second potential "neuronitis".
» Labyrinthitis: ˃ a combination of the symptoms of vestibular neuritis, with the addition of hearing symptoms. ˃ It may be due to a process that affects the inner ear as a whole, or due to a process that affects the 8th nerve as a whole. ˃ Labyrinthitis is also always attributed to an infection. » Vestibular neuritis and labyrinthitis are rarely painful ˃ -when there is pain it is particularly important to get treatment rapidly as there may be a treatable bacterial infection or herpes infection.  (Hain T, 2003) » Central compensation occurs, and the condition resolves over time. » Even when nystagmus is present, it is important to begin vestibular training with having the patient focus on a target with head movement in all directions, and eye-head coordination exercises. » Helpful exercises are to have the patient focus on a target while moving the head up and down and side to side. » Balance exercises are incorporated as soon as possible. » Medication may be needed during the acute phase.  (Hain T, 2003) (Hain T, 2003) » Diligence and perseverance are required. » The earlier and more regularly the exercise regimen is carried out, the faster and more complete will be the return to normal activity. » Ideally these activities should be done with a supervised group. » Individual patients should be accompanied by a friend or relative who also learns the exercises.
» Head trauma is the most common cause (eg direct blow to the ear). » Fistulas may also develop following rapid or profound changes in intracranial or atmospheric pressure, such as may occur with SCUBA diving, or even just dives into a swimming pool (Klingmann et al, 2007;Rozsasi et al, 2003). » In pregnancy, collagen changes throughout the body, and fistulae may arise spontaneously or in association with delivery. » Children are likely more prone to develop fistulae because of more widely open pathways between the inner ear and the spinal fluid. » Ear surgery, eg for otosclerosis, often creates a fistula. » Some patients develop a fistula, following airplane descent. » Fistulas may be present from birth (usually in association with deafness) or may result from chronic ear infections.
Dr Rudi Gerhardt 13 6 25/10/2014 » Changes in air pressure in the middle ear normally don't affect the inner ear. » When a fistula is present, changes in middle ear pressure will directly affect the inner ear, stimulating the balance and/or hearing structures within and causing symptoms. » There is no classic presentation because onset, intensity, and frequency vary. » Many patients have a history of barometric pressure changes, as with diving or air flight, or internal pressure development through intense weight lifting. » Symptoms may include dizziness, vertigo, imbalance, nausea, and vomiting. » Usually however, patients report an unsteadiness which increases with activity and which is relieved by rest. » Some people experience tinnitus or aural fullness, many notice a hearing loss. » Symptoms may get worse with coughing, sneezing, or blowing their noses, as well as with exertion and activity. » "Valsalva induced dizziness" can also be associated with other medical conditions in for example, the Chiari malformation.
Dr Rudi Gerhardt 13 7 25/10/2014 » Opening develops between the middle and inner ear (oval or round window rupture), allowing leakage of perilymph. » Perilymphatic fistulas are a rare cause of vertigo. » 'Dehiscence' is similar to a fistula, but not as severe. » Bone is missing, over one of the semicircular canals, uncovering a membrane. » This dehiscence makes the ear more sensitive to pressure and noise.

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Dr Rudi Gerhardt 25/10/2014 » Meniere's disease, which is much more common than fistula, can have identical symptoms, including pressure sensitivity. » For this reason, fistula diagnoses made in patients without barotrauma are easily questioned. » Oval window fistulae are often accompanied by hyperacusis and tinnitus. » Oval window fistulae are largely caused by very loud noises. » Round window fistulae are mainly characterized by exercise induced dizziness. » These types of fistulae are mainly induced by barotrauma, such as airplane flights or SCUBA diving. » The Valsalva Test changes pressure in perilymph, and thus might be positive in fistula. » There are small amounts of horizontal nystagmus in many persons with dizziness, lacking a diagnosis.

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Dr Rudi Gerhardt 25/10/2014 (Hain T, 2013) » In ~90%, a window fistula fistula will heal itself if activity is restricted. » Avoidance of activities where there is a possibility of creating high pressure (e.g. airplane travel, Scuba diving, power lifting, horn playing, etc) is usually advised. » It is usual to wait 6 months before embarking on surgical repair, given that hearing function is reasonable and is stable or improving. » It is believed that either overstimulation of upper cervical proprioceptors or degeneration of these proprioceptors or their pathways may cause an imbalance of information leading to a perception of vertigo or disequilibrium.
14 3 Dr Rudi Gerhardt 25/10/2014 » Findings of upper cervical soft tissue involvement and restricted movements are possible. » The Fitz-Ritson rotation test may help differentiate. » The examiner stabilizes the patient's head while the patient rotates his or her body in a chair. » If the patient becomes dizzy, a vertebrogenic source is suggested because it is believed that vestibular stimulation is eliminated with this maneuver.
14 4 Dr Rudi Gerhardt 25/10/2014 » Cervical manipulation may be beneficial and should be applied as a treatment trial . » It is important to consider that because of the proprioceptive input of the upper cervical area, cervical manipulation may serve to benefit other causes of vertigo or that there may be an overlap between cervicogenic vertigo and other types.
Dr Rudi Gerhardt 15 1 25/10/2014 (Hain T, 2003) » Hearing loss is occurring in > 95% of patients with AN. »~ 90% with a one-sided, slowly progressive hearing impairment » Tinnitus: very common in AN, is usually unilateral & confined to affected ear. » Vertigo occurring in only ~20 % of persons with AN. (Krais et al, 2007). » Unsteadiness is much more prevalent than vertigo, ~70% of patients with large tumors have this symptom. » Cerebellar symptoms are unusual. » Numbness in the face occurs only in large tumors (~ 50 % of >2 cm in size). » Facial weakness is uncommon. » Facial twitching (hemifacial spasm), occurs in ~ 10% of patients. » Headache prior to surgery occurs in ~ 40% of those with large tumors. » Unless the tumor is large and pressing on other cranial nerves, there are likely to be no additional clinical findings. » When the suspicion is high, an MRI should be ordered. » It is the definitive diagnostic tool.  Dr Rudi Gerhardt (Serre, 1985) 25/10/2014 Dr Rudi Gerhardt 15 5