Flashcards in CN LANGE - Disorders Of Equilibrium II Deck (100):
POSITIONAL vertigo and nystagmus are usually associated with ...?
Peripheral vestibular lesions and are most often a feature of BPPV.
BPPV - Typically characterized by ...?
1. Severe distress.
2. A latency of several seconds between assumption of the position + the onset of vertigo/nystagmus.
3. A tendency for the response to remit spontaneously (fatigue) as the position is maintained.
4. Attenuation of the response (habituation) as the offending position is repeatedly assumed.
Can positional vertigo occur with CENTRAL vestibular disease?
Disorders of the vestibuloocular pathways can be detected by ...?
What should precede caloric testing?
Careful otoscopic examination and should NOT be undertaken if the tympanic membrane is perforated.
In the normal, awake patient, COLD-water caloric stimulation produces nystagmus with the ...?
SLOW phase --> TOWARDS the irrigated ear.
FAST phase --> AWAY from the irrigated ear.
(Warm water irrigation produces the OPPOSITE respone)
In patients with unilateral labyrinthine, vestibulocochlear (VIII) nerve, or vestibular nuclear dysfunction, irrigation of the affected side ...?
FAILS to cause nystagmus OR elicits nystagmus that is later in onset or briefer in duration than on the normal side.
Papilledema + Disequilibrium = ...?
Intracranial mass lesion, usually in the POSTERIOR FOSSA, causing incr. ICP.
Optic atrophy may be present in ...?
3. B12 def.
A depressed corneal reflex or facial palsy IPSILATERAL to the lesion (and the ataxia) can accompany ...?
CEREBELLOPONTINE ANGLE TUMOR.
Characteristics of positional nystagmus - Peripheral vs Central:
Peripheral --> Severe vertigo + Latency 2-40s + Fatigability + Habituation.
Central --> Mild vertigo + NO latency + NO fatigability + NO habituation.
Motor system - Exam of the motor system in a patient with a disorder of equilibrium should disclose ...?
The PATTERN + SEVERITY of ataxia + any associated:
3. LMN involvement.
--> Might suggest the cause.
Muscle tone exam - Hypotonia is characteristic of ...?
CEREBELLAR disorders --> With unilateral cerebellar hemispheric lesions --> IPSILATERAL limbs = hypotonic.
Muscle tone exam - Extrapyramidal hypertonia (rigidity) may occur in disorders that affect ...?
CEREBELLUM + BASAL GANGLIA.
Disorders that affect both cerebellum and basal ganglia:
2. Acquired hepatocerebral degeneration.
4. Some spinocerebellar ataxias.
Muscle tone exam - Ataxia + spasticity may be seen in condition that affect ...?
CEREBELLUM + UMN diseases.
Mention some conditions that affect CEREBELLUM + UMN:
2. Posterior fossa tumors.
3. Congenital anomalies of the posterior fossa.
4. Vertebrobasilar infarction.
5. Some spinocerebellar ataxias.
7. B12 def.
Coordination exam - Truncal stability is assessed by examining ...?
Gait + Observing the seated, unsupported patient.
Coordination exam - In addition to gait ataxia, patients with MIDLINE or PANCEREBELLAR disease may show ...?
OSCILLATION OF THE HEAD (titubation) + truncal ataxia while seated --> Tendency to fall over when they sit.
Coordination exam - Other features:
1. Intention tremor.
3. Ataxia of the legs.
4. Ataxia of any limb.
Ataxia of any limb is demonstrated by irregularity in the ...?
RRAF = rate, rhythm, amplitude, and force of rapid successive tapping movements.
Weakness - PURE vestibular, cerebellar, or sensory disorders ...?
DO NOT CAUSE WEAKNESS.
(weakness may occur in disorders that also affect motor pathways)
Distal weakness can be caused by disorders that also produce SENSORY ataxia, such as ...?
2. Friedreich ataxia.
Paraparesis may be superimposed on ataxia in ...?
1. B12 def.
3. Foramen magnum lesions.
4. Spinal cord tumors.
Ataxic quadriparesis, hemiataxia with contralateral hemiparesis, or ataxic hemiparesis suggests ...?
Abnormal involuntary movements - Titubation and intention tremor are common in ...?
--> Other abnormal movements can occur with diseases that affect BOTH the cerebellum and other brain structures.
Abnormal involuntary movements - Asterixis may occur in ...?
1. Hepatic encephalopathy.
2. Other acute metabolic encephalopathies.
3. Acquired hepatocerebral degeneration.
Abnormal involuntary movements - Myoclonus occurs in ...?
The SAME conditions as ASTERIXIS.
--> Prominent in CJD.
Abnormal involuntary movements - Chorea:
May accompany cerebellar signs in:
2. Acquired hepatocerebral degeneration.
Sensory system exam:
1. Joint position sense.
2. Vibration sense.
Reflexes exam - Tendon reflexes are typically ... in cerebellar disorders.
HYPOACTIVE with a PENDULAR quality.
--> UNILATERAL cerebellar lesions produce IPSILATERAL HYPOREFLEXIA.
Reflexes - Hyporeflexia of the legs is a PROMINENT manifestation of:
1. Friedreich ataxia.
2. Tabes dorsalis.
--> cause SENSORY ataxia.
Reflexes - HYPERACTIVE reflexes and extensor plantar responses may accompany ATAXIA caused by ...?
2. B12 def.
3. Focal brainstem lesions.
4. Certain AD spinocerebellar ataxias.
Investigative studies - Blood tests:
1. B12 def.
3. Elevated LFTs + low ceruloplasmin + low Cu = WILSON.
4. Ig deficiency + Elevated AFP = Ataxia-telangiectasia.
5. Antibodies to Purkinje cell antigens in paraneo cerebellar degeneration.
6. Mutations associated with certain AD spinocerebellar ataxias + Friedreich.
Investigative studies - CSF shows ELEVATED PROTEIN with:
1. Cerebellopontine angle, brainstem, or spinal cord tumors.
3. Some polyneuropathies.
CSF - Increased protein + pleocytosis is found in:
1. Infectious or parainfectious encephalitis.
2. Paraneo cerebellar degeneration.
CSF - Other useful clues:
1. 14-3-3 in CJD.
2. Elevated pressure + blood = Cerebellar hemorrhage (DO NOT LP).
3. CSF VDLR = Tabes dorsalis.
4. Oligoclonal IgG bands may be present in MS or other inflammatory disorders.
Investigative studies - Brain imaging - CT can demonstrate:
1. Posterior fossa tumors or malformations.
2. Cerebellar infarction or hemorrhage.
3. Cerebellar atrophy associated with degenerative disorders.
MRI provides better visualization of ...?
Posterior fossa lesions, including cerebellopontine angle tumors + superior to CT for MS lesions.
Investigative studies - Evoked potentials - Visual evoked potentials:
Especially of optic pathways, may be helpful in evaluating patients with suspected MS.
Brainstem AUDITORY evoked potentials can localize ...?
Vestibular disease to the peripheral vestibular pathways and may help identify cerebellopontine angle tumors.
Investigative studies - CXR and echocardiography:
1. Evidence of cardiomyopathy = Friedreich ataxia.
2. May show lung tumor in paraneo cerebellar degeneration.
Investigative disorders - Audiometry - Useful in vestibular disorders associated with auditory impairment - Can distinguish:
4. Brainstem disease.
1. Markedly impaired = VIII nerve lesions.
2. Less impaired = Labyrinthine disorders.
3. Normal = Conductive hearing loss or brainstem disease.
When a patient indicates that vertigo occurs with a change in position, which maneuvers are used to try to reproduce the precipitating circumstance?
The Nylen-Barany or Dix-Hallpike maneuver.
PERIPHERAL vestibular disorders - DDx:
3. Acute peripheral vestibulopathy.
5. Head trauma.
6. Cerebellopontine angle tumor.
7. Toxic vestibulopathy (alcohol, aminoglycosides, salicylates, quinine).
8. VIII neuropathy.
9. Basilar meningitis.
Peripheral vestibular disorders - DDx - Conductive hearing loss:
2. Head trauma (+/-).
Peripheral vestibular disorders - DDx - Sensorineural hearing loss:
3. Head trauma (+/-).
4. Cerebellopontine angle tumor.
5. Toxic vestibulopathy (EXCEPT alcohol).
6. All causes of VIII neuropathy (basilar meningitis, hypothyroidism, DM, Paget).
Peripheral vestibular disorders - DDx - Other cranial nerve palsies:
1. Head trauma.
2. Cerebellopontine angle tumor.
3. Basilar meningitis.
MCC of vertigo of peripheral origin:
BPPV - 30% of cases.
The pathophysiologic basis of BPPV is thought to be ...?
Canalolithiasis --> Stimulation of the semicircular canal by debris floating in the endolymph.
BPPV - Symptoms are usually worse in which position?
LATERAL DECUBITUS POSITION WITH THE AFFECTED EAR DOWN.
BPPV - Mainstay of treatment:
Repositioning (Epley) maneuvers that use the force of gravity to move endolymphatic debris out of the semicircular canal and INTO THE VESTIBULE, where it can be reabsorbed.
Meniere disease - Characterized by ...?
Repeated episodes of vertigo lasting from MINUTES to DAYS, accompanied by tinnitus and progressive sensorineural hearing loss.
Meniere - Pathogenesis:
1. Most sporadic.
2. Familial occurrence has been described + may show ANTICIPATION.
3. Rare cases appear to be related to mutations in the COCH (coagulation factor C homology) gene, which codes for COCHLIN.
Cochlin is a components of the ...?
Inner ear ECM.
Meniere - Epidemiology:
1. Onset = 20-50.
2. Men > Women.
Meniere - Cause:
An increase in the volume of labyrinthine endolymph (endolymphatic hydrops), but the pathogenetic mechanism is UNKNOWN.
Meniere - Clinical findings - At the time of the 1st acute attack, patients already may ...?
Have noted the insidious onset of:
2. Hearing loss.
3. Sensation of fullness in the ear.
Meniere - Hearing deteriorates in a ...?
Stepwise fashion, with bilateral involvement in 10% to 70% of patients.
--> As hearing loss increases, vertigo tends to become less severe.
Meniere - Physical exam DURING AN ACUTE EPISODE shows ...?
Spontaneous HORIZONTAL or ROTATORY nystagmus (or both) that may change direction.
Meniere - Treatment:
1. Symptomatic management of acute attacks (antihistamines, benzos).
2. Between attacks --> May be treated with a low-salt diet + diuretics (HCTZ - 50mg/d orally + Triamtere - 25mg/d orally), or with H3 blockers (8-24mg/3x per day, orally).
Meniere - Treatment in persistent, disabling cases?
1. Vestibular ablation by intratympanic gentamicin.
2. VIII nerve section.
3. Labyrinthectomy may be beneficial.
Acute peripheral vestibulopathy - This term is used to describe ...?
A spontaneous attack of vertigo of INAPPARENT cause that resolves spontaneously and is NOT accompanied by HEARING LOSS or CNS dysfunction.
Acute peripheral vestibulopathy - Includes disorders diagnosed as ...?
Acute labyrinthitis or vestibular neuronitis and may follow a febrile illness.
Acute peripheral vestibulopathy - Features:
Acute onset of vertigo, nausea, and vomiting, typically lasting up to 2 weeks.
--> Symptoms may recur, and some vestibular dysfunction may be PERMANENT.
Acute peripheral vestibulopathy - During an attack the patient appears ...?
Acutely ill, typically lies on one side with the affected ear UPWARD, and is reluctant to move the head.
--> Nystagmus with the fast phase AWAY from the affected ear is ALWAYS present.
Acute peripheral vestibulopathy - Auditory acuity?
Acute peripheral vestibulopathy - DDx:
Must be distinguished from:
1. Central causes of acute vertigo, such as stroke in the posterior cerebral circulation.
2. CENTRAL disease is suggested by:
a. Vertical nystagmus.
b. Altered consciousness.
c. Motor or sensory deficit.
Acute peripheral vestibulopathy - Treatment:
10- to 14-day course of PREDNISONE, 20mg orally/2x daily.
Otosclerosis is caused by ...?
IMMOBILITY of the STAPES --> The ear ossicle that transmits vibration of the tympanic membrane to inner ear.
Otosclerosis - Most distinctive features:
1. Conductive hearing loss.
2. Sensorineural hearing loss and vertigo may also occur.
3. Tinnitus is INFREQUENT.
4. Auditory symptoms begin before 30 years of age + Familial occurrence is common.
Otosclerosis - When vestibular dysfunction occurs, it is most often characterized ...?
By recurrent episodic VERTIGO - with or without positional vertigo + a sense of positional imbalance.
Otosclerosis - Vestibular abnormalities on exam include:
Spontaneous or positional NYSTAGMUS of the peripheral type + attenuated caloric responses, usually UNILATERAL.
Otosclerosis - Hearing loss:
ALWAYS demonstrable by audiometry - It is usually of mixed conductive-sensorineural character and is BILATERAL in approx. 2/3 of patients.
In patients with episodic vertigo, progressive hearing loss and tinnitus, otosclerosis must be distinguished from ...?
Otosclerosis is suggested by ...?
1. Positive FHx.
2. Tendency toward onset at an earlier age.
3. Presence of conductive hearing loss, or bilateral symmetric impairment.
--> Imaging studies may be diagnostically useful.
Otosclerosis - Treatment with:
1. Sodium fluoride.
3. Intratympanic dexamethasone may be effective.
--> If NOT --> Surgical stapedectomy should be considered.
MC identified cause of benign positional vertigo:
Head trauma - Vertigo via which mechanism?
1. Injury to the labyrinth is usually responsible.
2. Fractures of the petrosal bone may lacerate the VIII nerve, producing vertigo + hearing loss.
3. Hemotympanum or CSF otorrhea suggest petrosal bone fracture.
Cerebellopontine angle tumors - Which tumors?
1. Acoustic neuroma (Schwannoma).
3. Primary cholesteatomas (epidermoid cysts).
Acoustic neuromas usually occur as ...?
ISOLATED lesions in patients 30-60yrs old - May also be a manifestation of neurofibromatosis.
1. UNILATERAL acoustic neuromas.
2. Cafe au lait spots on the skin.
3. Cutaneous neurofibromas.
4. Axillary or inguinal freckles.
5. Optic gliomas.
6. Iris hamartomas.
7. Dysplastic bony lesions.
NF2 - Associations:
1. Bilateral acoustic neuromas.
2. Central or peripheral nerve system tumors: Neurofibromas+ meningiomas + gliomas + schwannomas.
Cerebellopontine angle tumor - Pathophysiology - Symptoms are produced by ...?
1. Compression or displacement of the cranial nerves, brainste, and cerebellum + CSF flow obstruction.
2. VIII + VII + V are often affected.
Cerebellopontine angle tumor - Clinical findings - Symptoms:
1. Insidious hearing loss = INITIAL SYMPTOM.
2. Less often, patients present with headache, vertigo, gait ataxia, facial pain, tinnitus, a sense of fullness in the ear, or facial weakness.
3. Vertigo ultimately in 20-30% - Non specific unsteadiness is more common.
Cerebellopontine angle tumor - MC finding in exam:
UNILATERAL sensorineural hearing loss.
Cerebellopontine tumors - Lab:
1. Audiometry --> Sensorineural deficit (high-freq).
2. CSF protein elevated in 70% --> 50-200mg/dL.
3. Acoustic neuromas --> Brainstem auditory evoked potentials.
Cerebellopontine angle tumor - DDx of acoustic neuromas:
1. Meningiomas --> If initial symptoms are more than isolated VIII nerve disease.
2. Cholesteatoma --> Conductive hearing loss, early facial weakness/facial twitching, with normal CSF protein.
3. Metastatic carcinoma.
Toxic vestibulopathies - Alcohol causes acute positional vertigo because of ...?
Differential distribution between the CUPULA and ENDOLYMPH of the inner ear.
Alcohol-induced positional vertigo typically occurs within ...?
2 HOURS after ingesting ethanol in amounts sufficient to produce blood levels greater than 40mg/dL.
Alcohol - Course:
Alcohol initially diffuses into CUPULA --> Later also diffuses into the ENDOLYMPH, and then leaves the cupula BEFORE it leaves the ENDOLYMPH.
What is the result of this alcohol route from the cupula to the endolymph?
Produces 2 symptomatic phases of vertigo, which together last about 12 HOURS, separated by an ASYMPTOMATIC interval of 1 to 2 HOURS.
Alcohol - Acute positional vertigo - The clinical syndrome is characterized by ...?
Vertigo + Nystagmus in the LATERAL RECUMBENT POSITION and is accentuated when the eyes are closed.
Toxic vestibulopathies - Aminoglycosides:
Widely recognized ototoxins that can produce BOTH vestibular and auditory symptoms.
Which aminoglycosides are most likely to cause VESTIBULAR toxicity?
Which aminoglycosides are most likely to cause HEARING loss?
Aminoglycosides - Toxicity - Mechanism?
Concentrate in the perilymph + endolymph --> Destroy sensory hair cells.
Which antineoplastic drug causes BILATERAL + IRREVERSIBLE ototoxicity in a high percentage of patients?