Disorders of Equillibrium Flashcards
Balance and awareness of body position in relation to surroundings requires input from 2 of the following 3 systems…
- Visual–to judge distance
- Labyrinthine–to judge acceleration and position change
- Proprioceptive–to judge posture
A positive Romberg test indicates what?
Somatosensory dysfunction (proprioception)
- *With the eyes open, 3 sensory systems (vision, proprioception, and vestibular sense) provide input to the cerebellum to maintain balance
- When pt closes eyes during Romberg test you remove that visual sense => thus, if problem, problem is [propioception] or [vestibular/labyrinth]
- Romberg is NOT a test of cerebellar fx: these pts cannot stand with feet apart with eyes open OR closed
Realize the non-specific nature of the complaint of “poor balance”.
A sx, not a dx; means different think to different people; so you 1st have to define the symptoms and determine if it is central or peripheral
Illusion of movement of oneself or objects around self due to vestibular or neurologic dysfunction
Vertigo
Vertigo is often accompanied with what symptoms?
Sweating and nausea, sometimes associated with hearing impairment or tinnitus.
May be caused by vertigo but usually a nonvertiginous state of altered static or dynamic balance due to dysfunction of cerebellum, dorsal columns (sensory), motor systems (central or peripheral) or basal ganglia
Disequilibrium
Lightheadedness or impending LOC often due to orthostasis, arrhythmia, hyperventilation and aggravated by high temperature, prolonged standing, large meals
Presyncope
Vertigo is often due ot vestibular dysfunction of what structures?
Semicircular canal/otoliths
What are the main characteristics of sensory causes of Disequilibrium?
- Problem with propioception
- Visual impairment
- Compensated vestibular disorders
- Worse in dark
- Romberg sign
What are the main characteristics of motor causes of Disequilibrium?
- NO Romberg Sign
- Mechanical (arthritis)
- Peripheral or central (motor function).
What are the main characteristics of cerebellar causes of Disequilibrium?
- NO Romberg sign (cannot stand with feet together with eyes open or closed)
Peripheral/labyrinthine structures important to maintain equilibrium?
- 1. Utricle
- 2. Saccule
- 3. Semicircular canals
- 4. Vestibular nerve
Central structures important to maintain equilibrium?
- Cerebellum
- Vestibular nuclei
- Vestibulospinal
- Proprioceptive pathway
With Peripheral/labyrthine causes of dysequilibrium:
what is the vertigo like, duration of nystagmus, direction of nystagmus, and neuro symptoms?
- Intense vertigo
- Brief nystagmus
- FIXED horizontal/diagonal nystagmus (may be latent)
- NEVER neuro symptoms
With central dysfunction leading to dysequilibrium what is the vertigo like, duration of nystagmus, direction of nystagmus, and neuro symptoms?
- Mild vertigo
- Persistant nystagmus, which can be in vertical direction, but can change directions
- Usually some neuro symptoms
Is N/V more intense in central or peripheral causes?
Peripheral (intense)
Hearing loss is MC with ____ causes of dizziness.
Peripheral; rare in centrla
6 peripheral causes of vertigo
- Benign positional vertigo
- Vestibular neuronitis
- Meniere’s Disease
- Superior canal dehiscence
- Mal de Debarquement
- Drug induced ototoxicity
Most common cause of recurrent vertigo and characteristics?
- Benign Positional Vertigo: Brief recurrent episodes of vertigo triggered by changes in head positon
- What is Benign Positional Vertigo thought to be due to?
- How is this diagnosed?
- Direction of Nystagmus?
- Debris floating in endolymph of semicircular canal, MC posterior semicircular canal.
- Dix-Hallpike maneuver w/ affected ear down => causes TORSIONAL nystagmus
- Torsional
Dix-Hallpike maneuver should NOT be done in ________.
Spontaneous nystagmus, because you are trying to PROVOKE the nystagmus. Thus, only use for episodic.
BPV due to debris in horizontal semicircular canal
- Test:
- Nystagmus
- Supine Roll Test (Pagnini-McClure)
- Horizontal; changes direction
BPV due to debris in anterior semicircular canal
- Test:
- Nystagmus
- Dix Hallpike with the affected ear UP
- Downbeat and torsional
A patient with vertical positional nystagmus, such as seen in BPV with anterior semicircular canal affected requires what?
CAREFUL assessment to R/O brainstem or cerebellar lesions.
Treatment for Benign Postional Vertigo?
- Goes away on its own in a few weeks
- Positional exercises helpful: Sermont manuever
- Meds such as: vestibular suppressants, antiemetics, and anxiolytics
- PT: vestibular rehab/balance therapy
How does Vestibular Neuronitis differ from BPV?
- Spontaneous attack of vertigo, typically l_asting up to 2 weeks_ (findings similar to BPV) due to inflammation of CN 8; acute vertigo, N/V that peaks in 24 hours & NO hearing loss or tinnitus
- But is NOT positonal
What are the characteristics of Meniere’s Disease and who is most often affected?
Hallmarks?
- Recurrent episodes of spontaneous vertigo, lasting >20min to hours, but less than 24 and dysequillibrium that can last several days.
- Hallmark = Low frequency hearing loss
- Tinnitus
- Aural fullness “fullness in ear”
- Woman are 3x more affected (20-50YO)
What is Menieres Disease thought to be due to?
⬆︎ in the volume of endolymph in labyrinthe because of poor absorption (endolymphatic hydrops)
Treatment for Meniere’s Disease?
Get rid of excess fluid (1 &2**)
- -* Sodium restriction
- -* Diuretics: thiazdies, furosemide
- Sympmatic: lorazepam and diazepam
- Sugery: endolymphatic sac decompression
What are the characteristics of Mal de Debarquement (“Sickness of Disembarkment”)?
Duration?
Treatment?
- Illusion of movement as an after effect of travel (sea, car, train)
- Rocking, swaying feeling after getting off a boat almost immediately after the precipitating event (RARELY true vertigo)
- Duration = usually <24 hours; sometimes longer
- Tx: meclizine, scopolamine, benzodiazepines (dizziness meds)
What are some of the drug induced causes of peripheral disequilibrium?
- Alcohol!
- Antibiotics - aminoglycosides, tetracycline, vancomycin
- Aspirin (salicylates)
- Diuretics
- -Chemotherapeutics: cisplatin, methotrexate, vincristine
Disorders that are central causes of vertigo/dysequillibrium
- 1. Vestibular migraine
- 2. Infections
- 3. Toxins/metabolic
- 4. Cerebellopontine Angle Tumors
- 5. Chiari malformation
- 6. SCA (spinocerebellar ataxias)
What are the requirements of diagnosis for a Vestibular Migraine (central)?
- At least 5 episodes of moderate/severe vestibular sx’s lasting 5min => 72 hours
- Current or previous hx of migraine w/ or w/o aura
- At least 50% of episodes have 1 or more migraine features: HA (unilateral, pulsatile), photophobia, phonophobia, nausea, aura…
Central: Vascular (ischemic) causes of equilibrium disoders are most commonly seen in?
Elderly; abrupt onset with ischemia of labyrinth, brainstem or both.
Repeated episodes of isolated vertigo without neurological symptoms should always suggest?
A non-neurologic cause
What helps to distinguish brainstem lesion (esp. stroke) from peripheral lesion in a patient with an acute (not chronic) vestibular syndrome. More sensitive than MRI to detect acute stroke.
HINTS Test: Head Impulse-Nystagmus-Test of Skew
- Test nystagmus: spontaneous and gaze-evoked
- Test skew deviation: look for ocular misalignment (tell pt to look at docs nose and cover each eye; do many times)
- HIT (Head impulse test): move laterally 20 degrees and return rapidly back to midline everytime; switch
When is a HINTS test abnormal => central cause/stroke?
- NL HIT test
- Nystagmus that is bidirectional or changes direction
- Presence of skew deviation
HiNTs exam=> peripheral vertigo
- Positive/ABNL head impulse test,
- Unidirectional and horizontal nystagmus,
- Negative skew test
What bacterial infections => central cause of dyequillibrium
- Meningococcal
- Pneumococcal
- H. flu
If you see a vertical nystagmus, think of ______ as the cause.
CENTRAL = almost always pathomneumonic for brainstem dysfunction
- Can also be BPV due to anterior semi-circular canal.
How to perform Dix-Hallpike Maneuver for posterior- BPV?
- Have pt sit on bed.
- Turn patients head 45 degrees TOWARD L ear
- Lay patient down, with head hanging off bed and look at eyes.
- = Torsional nystagmus (may not occur right away bc there is a latent period)
What are metabolic and toxic (central) causes of dizziness?
- VitB12 deficieny
- Hypothyroidism
- Wilsons Disease
- Toxins: glue, ethanol (chronic alcohol affects cerebellar vermis)
- What are Cerebellopontine Angle Tumors that are central causes of dizziness?
- What do they usually affect?
- Acoustic neuroma (Schwannoma)
- Meningioma
- Cholesteatoma
Usually affect CN 5, 7, 8.
What is the first sign and the first symptom of a Cerebellopontine Angle Tumor?
- - First symptom = hearing loss (CN VIII)
- - First sign = absent corneal reflex (loss of CN V and VII)
Paraneoplastic Cerebellar Degeneration is a central cause of dizziness: they can PRECEDE cancer diagnosis.
- Most commonly associated with what cancers?
- Antbodies cross react with?
- Breast, ovary and lung
- Ab to tumor cell antigens that attack Purkinje cells in the cerebellum.
What are the most common forms of Spinocerebellar Ataxias?
Characteristic findings in these diseases?
- SCA 1 (olivopontocerebellar)
- SCA 3 (Machado-Joseph)
*Slowly, progressive cerebellar ataxia of limbs + brainstem signs (dysarthria, oculomotor disturbance, spasticity) + peripheral neuropathy. Affect gait early => bed confinment => all => death
When is the typical onset of Friedrich’s Ataxia and what are the common findings?
- AR disorder due to mutation on Chr9 that appears before 20 YO (young persons disease)
- - Gait ataxia w/ absent tendon relfexes in legs and muscle weakness
- Extensor plantar responses
- Pes cavus
- Kyphoscoliosis
Common cause of death in someone with Friedrich’s Ataxia?
Cardiomyopathy: death by 35 YO
What is the age of onset for LOFA (Late-onset Friedrichs Ataxia)?
After 25 YO: less dramatic course
Age of onset for Ataxia-Telangiectasia?
Common findings?
- Disease of infancy (<4 yr. of age)
- Progressive pancerebellar degeneration involving nystagmus, dysarthria, and [gait, limb and trunk ataxia], oculoculocutaneous telangiectasia** (port-wine stain from forehead => eye) and immunodeficiency**.
- Choreoathetosis, loss of vibration and position sense in legs, areflexia, and disorders of voluntary eye movements
What age does Oculocutaneous telangiectasia usually appear?
Common findings?
- Usually appears in teens
- - Immunological impairment (⬇︎ IgA and IgE) usually evident later on => causing recurrent sinopulmonary infections
- Changes of skin and hair, hypogonadism, and insulin resistance
- Where is Spondylosis (degenerative changes of spine) most commonly seen?
- Can lead to?
- Early signs?
- Cervical region
- Can lead to myelopathy (spondylotic), compress SC and/or nerve roots
- Unexplained gait impairment or imbalance often an early symptom in OLDER PPL
What will examination of someone with Spondylotic Myelopathy show?
- MCC of myelopath in elderly (>55 YO)
- Spastic tone in legs
- ⬆︎ knee/ankle jerks
- Babinski signs
- Variable sensory deficits
What can cause B12 deficiency?
- Malabsorption syndromes (bc binds to intrinsic factor in duodenum and absorbed in ileum)
- Surgery (gastric bypass, ileectomy)
- Drugs (H2 receptor antagonists)
- Nitrous oxide (whip-its!!!)
- Fish tapeworm
Can all lead to => degeneration of posterior colum and lateral corticospinal tract (combined systems degeneration); + peripheral neuropathy and dementia
What does VitB12 do?
- Homocysteine => methionine
- Methymelonic acid => SucCoA
Clinical fx of Vit B12 deficiency
- Insidious onset
- V tired
- + Rhomberg and Babinksi
- Gait and balance problems
Diagnosis of VitB12 deficiency
- +/- anemia
- +/- hypersegmented polys
- ↓ serum B12
- ↑ homocysteine and methylmalonic acid
- Presence of clinical syndrome
What type of syndrome can be caused by Vitamine E deficiency?
Spinocerebellar similiar to Friedrich’s
The syndrome associated with Copper deficiency (DECREASED urine Cu and DECREASE serum ceruloplasmin) can present very similar to what?
B12 deficiency
How is diagnosis of Nitrous Oxide Toxicity made and what is the treatment?
- Diagnosis: HX and ⬇︎ of Vit B12 w/ similar symptoms
- Tx: B12 replacement
