Central Vestibular Pathology

Question 1

Describe the complete differential diagnosis of central vestibular disorders

Answer 1

A. TOXIC/METABOLIC/MEDICATIONS

B. VASCULAR HEADACHE
1. Migraine with/without aura, basilar migraine
2. BPV/Recurrent vertigo of childhood
3. Tension or Cluster headaches
4. Vertebrobasilar insufficiency

C. BRAINSTEM
1. Lateral medullary infarction (Wallenberg syndrome, PICA)
2. Lateral pontomedullary syndrome (AICA)
3. Subclavian Steal Syndrome
4. Cerebellar infarction or hemorrhage
5. Orthostatic hypotension
6. Labyrinthine Apoplexy
7. Paroxysmal Torticollis
8. Infectious
9. Meningitis
10. Encephalitis
11. Epidural abscess
12. Congenital Syphillis

D. CRANIOVERTEBRAL JUNCTION DISORDERS
- Basilar impression (CRROOP)
- Assimilation of the Atlas – C1 fused to Skull, Odontoid compression, Klippel-Feil
- Atlantoaxial dislocation – Odontoid compression due to laxity of the transverse ligaments; can be Congenital (Down, Achondroplasia), or Acquired (R/A, RPA, Griesel)
- Chiari malformation
- Syringobulbia Neurologic
- Multiple sclerosis
- Huntington
- Parkinson
- Progressive Supranuclear Palsy
- Multiple Systems Atrophy
- Pseudotumor cerebri (BIH)
- Vestibular epilepsy
- Cerebellar ataxia syndromes
- Multisensory disturbances
- Waardenburg
- Cogan (Autoimmune)

E. NEOPLASTIC - PRIMARY OR SECONDARY
- Brainstem lesions
- Aqueduct/Ventricle compressing neoplasms
- Cerebellar neoplasms

Question 2

What percentage of dizziness is caused by central causes?

Answer 2

• 10-20%

Question 3

What medications can be used in the management of central vertigo?

Answer 3

1. Anticholinergics: Reduce vestibular neuro-excitability
2. Monoaminergics: Reduce vestibular neuroexcitability
3. Antihistamine: Histamine increases neural excitability
4. Antidopaminergic: Reduces excitatory effect from dopamine receptors

Question 4

What are the main branches of the vertebrobasilar system?

Answer 4

Vertebrobasilar system feeds the cerebellum

1. AICA: Anterior inferior cerebellar artery
2. PICA: Posterior inferior cerebellar artery
3. Superior cerebellar artery

Kevan Page 81

Question 5

Regarding Vertebrobasilar insufficiency, discuss:
1. What is the etiology?
2. What is the clinical presentation?

Answer 5

ETIOLOGY:
- Atherosclerosis of one or more of the subclavian arteries, vertebral arteries, or basilar arteries, leading to insufficiency of blood flow and subsequent vertigo
- The vertebrobasilar system feeds the cerebellum, inner ear, and brainstem
- Rarely, may be due to subclavian steal syndrome

CLINICAL PRESENTATION:
- Sudden onset nausea, vomiting, vertigo, lasting minutes (essentially like a brainstem TIA)
- Associated with other brainstem/cerebellar deficits: headaches, diplopia, ataxia, numbness, weakness, oropharyngeal dysfunction
- 4 D’s
1. Dizziness
2. Diplopia
3. Dysphagia / dysarthria
4. Drop attacks

Question 6

How is vertebrobasilar insufficiency treated In the acute and non-acute phase?

Answer 6

TREATMENT:
1. Acute Management
- If stroke suspected: CT to rule out hemorrhagic event
- If presents within 3 hours of onset of symptoms, get a Neurology consultation and IV tPA (NINDS guidelines)

2. Non-Acute management
   - Control of risk factors: Diabetes, HTN, dyslipidemia, smoking (e.g. antiHTNs, Statins)
   - Symptomatic 50-99% stenosis: ASA or Warfarin (Equally effective, but Warfarin high risk of intracranial events, and ASA therefore preferred. Warfarin should be used if prior embolic stroke that is cardiac in origin)
   - Platelet aggregation inhibitors (ticlopidine)
3. Non-acute Procedure Interventions:
   - Stenting has mixed restults
   - Endarterectomy for extracranial vertebral disease (indications are evolving)

Question 7

Regarding Subclavian Steal Syndrome, discuss:
1. What is it/what is the etiology?
2. What is the clinical presentation?
3. What is the management?

Answer 7

SUBCLAVIAN STEAL SYNDROME:
- Occlusion/stenosis of the subclavian/innominate artery just proximal to the takeoff of the vertebral artery
- Results in siphoning (drawing off) from the vertebrobasilar system, causing retrograde flow to supply the upper extremity during activity

CLINICAL PRESENTATION:
1. Similar symptoms to vertebrobasilar insufficiency with any arm movement/activity
- Vertigo
- Blurred vision
- Headache
- Arm pain
- Bruits
- Differential brachial BPs

TREATMENT:
1. Similar to vertebrobasilar insufficiency

Kevan Otology Page 82

Question 8

Regarding Chiari Malformations, discuss:
1. What are they?
2. What are the general symptoms?
3. What are the four types of chiari malformation?
4. What are other conditions associated with chiari malformations?

Answer 8

CHIARI MALFORMATIONS:
- Group of developmental hindbrain and spinal cord abnormalities
- Characterized by herniation of the contents of the posterior cranial fossa through the foramen magnum into the upper cervical spine

GENERAL SYMPTOMS:
- Ataxia, nystagmus, vertigo
- Occipital headaches
- Upper extremity weakness, pain, sensory loss
- May also have hydrocephalus, other CNS malformations

TYPES:
1. CHIARI I: Herniation of cerebellar tonsils through the foramen magnum > 5mm caudally
- Most common type is Syringomyelia
- Only type that can be acquired
- Often does not cause symptoms until adolescence or adulthood (sometimes referred to as adult Chiari malformation)

2. CHIARI II: Herniation of cerebellar tonsils and brainstem (Protrusion of cerebellar vermis, lower pons, and medulla)
   - aka. Arnold-Chiari malformation or Pediatric Chiari malformation
   - May also cause obstructive hydrocephalus in addition to symptoms of Type 1
   - Almost always associated with spina bifida
   - Frequently presents as a myelomeningocele
3. CHIARI III: Herniation of Hindbrain (cerebellum ± brainstem) through an encephalocele (high cervical meningocele)
   - Associated encephalocele, severe neurologic defects
4. CHIARI IV: Severe cerebellar hypoplasia or aplasia, without herniation
   - aka. Dandy-Walker syndrome
   - Controversial diagnosis, often considered obsolete

Other types from other sources:
1. Chiari 0: Syringomelia without hindbrain herniation
2. Chiari V: Cerebellar agenesis and occipital lobe herniation through the foramen magnum

Conditions associated with Chiari malformations:
1. Spina bifida
2. Syringomyelia
3. Hydrocephalus
4. Tethered cord syndrome

Question 9

Regarding Wallenberg Syndrome, discuss:
1. What is it, and what are other names for it?
2. What is the etiology?
3. What are the nuclei involved?
4. What are the clinical features?
5. What is the management?

Answer 9

WALLENBERG SYNDROME:
- aka. Lateral Medullary Syndrome
- Stroke of the PICA

ETIOLOGY:
- Infarction of the ipsilateral vertebral artery; OR
- Infarction of the ipsilateral posterior inferior cerebellar artery (PICA)
- Results in an infarction of a wedge of the DORSOLATERAL MEDULLA

Kevan Otology Page 82

Question 10

What are the nuclei involved in lateral medullary syndrome?

Answer 10

NUCLEI INVOLVED:
1. Vestibular Nucleus (Vertigo, N/V, nystagmus)
2. Nucleus Ambiguus - Motor IX/X (Dysphagia, dysarthria, decreased pharyngeal reflex)
3. Dorsal nucleus of X - Parasympathetic for X
4. Descending Sympathetic pathway (Ipsilateral Horner’s syndrome)
5. Spinal Trigeminal Nucleus (Ipsilateral decreased facial sensation)
6. Inferior cerebellar peduncle (Ipsilateral cerebellar ataxia, dysmetria)
7. Spinothalamic trunk (contralateral pain/temperature sensation loss)
8. Facial nucleus if extends rostral (high up) enough

Summary:
1. Ipsilateral CN V (spinal trigeminal), VIII-X (hearing spared)
2. Sympathetic chain
3. Spinothalamic tract (contra pain/temp)
4. Inferior Cerebellar Peduncle
5. ± Facial nucleus (if extends rostral enough)

Question 11

What are the clinical features of lateral medullary syndrome?

Answer 11

CLINICAL FEATURES:
1. Hallmark is contralateral pain/temperature deficits involving the trunk and extremities, with ipsilateral cranial nerve deficits
2. Sympathetic chain - Ipsilateral Horner’s Syndrome (ptosis, miosis, anhydrosis)
3. Vestibular nucleus - Spontaneous nystagmus
4. Ipsilateral facial pain, diplopia
5. Ipsilateral paralysis of palate, pharynx, larynx - dysphagia, dysphonia
6. Inferior Cerebellum Peduncle: Ipsilateral dysmetria, dysrhythmia, dysdiadochokinesia
7. Hearing loss not observed because the lesion is caudal to the cochlear nucleus
8. ± Ipsilateral facial nucleus

Question 12

What is the treatment for lateral medullary syndrome?

Answer 12

TREATMENT:
1. If caught acutely, within 3-4.5 hours post-onset, thrombolytics can be considered by Neurology
2. Endovascular revascularization (evolving field)
3. Otherwise, mainstay is supportive and symptomatic (enteral feeding, speech therapy, rehabilitation)

Question 13

Regarding Dejerine Syndrome, discuss:
1. What is it/alternative names?
2. What are the causes?
3. What are the nuclei involved, and their respective clinical features?
4. What is the management?

Answer 13

DEJERINE SYNDROME:
- Aka. Medial Medullary Syndrome

CAUSES:
- Infarction of the paramedian branches of the anterior spinal artery
- Results in infarction of the medial medulla, which includes the:
1. Hypoglossal nucleus
2. Medial Lemniscus
3. Pyramidal fibres

NUCLEI INVOLVED + CLINICAL PRESENTATION
1. Hypoglossal nucleus: Ipsilateral tongue weakness, ipsilateral tongue deviation, dysarthria
2. Pyramidal fibres: Contralateral upper extremity weakness (or hemiplegia) depending on degree of infarct
3. Medial lemniscus: Contralateral loss of 2-point discrimination, proprioception, and vibration sense

MANAGEMENT:
1. Similar to lateral medullary syndrome

Kevan Otology Pg 83

Question 14

Regarding Lateral Pontine Syndrome, discuss:
1. What are alternative names for this?
2. What are the causes?
3. What are the nuclei involed and subsequent clinical features?

Answer 14

LATERAL PONTINE SYNDROME:
- Aka. Marie-Foix syndrome
- Aka. Marie-Foix-Alajouanine Syndrome

CAUSES:
- Infarction of the Anterior inferior cerebellar artery (AICA)
- Middle cerebellar peduncle is typically the core of the affected territory
- Because the labyrinthine artery arises from the AICA in 80% of patients, comnbined cochleovestibular loss occurs in 60% of patients

NUCLEI INVOLVED / CLINICAL FEATURES:
1. Vestibular nucleus: Vertigo, N/V
2. Cochlear nucleus: Tinnitus, ipsilateral hearing loss
3. Spinal Trigeminal Nucleus: Ipsilateral decrease or changed facial sensation
4. Facial nucleus/CNVII: Ipsilateral facial weakness
5. Middle/Inferior Cerebellar Pedumcle: Ipsilateral cerebellar ataxia or dysmetria
6. Spinothalamic tract: Contralateral pain/temperature deficits
- Overall, onset of symptoms are acute and followed by gradual improvement

Question 15

What are the features that differentiate Lateral Medullary Syndrome and Lateral Pontine Syndrome? List 3 main ones

Answer 15

1. LMS presents with dysarthria and dysphagia, while LPS does not (does not involve IX/X)
2. LPS can present with hearing loss while LMS does not
3. LPS can present with facial weakness, while LMS does not

MNEMONICS:
1. Lateral medullary syndrome affects nucleus ambiguous and causes dysarthria and dysphagia
- PICA infarction results in ability to ‘chew’ –> PICA-CHEW (Pikachu)

2. Lateral Pontine syndrome may affect facial motor nucleus/facial nerve and cause facial weakness
   - AICA infarction results in fACIAl weakness (AICA backwards)

Question 16

Regarding Basilar Impression/Invagination, discuss:
1. What is it? Provide 3 definitions
2. Define the following: Chamberlain’s line, Wackenheim’s Clivus-Canal line, McRae Line, McGregor Line, Height Index of Klaus, Spinous Interlaminar Line (posterior canal line)

Answer 16

BASILAR IMPRESSION/INVAGINATION:
- Congenital or acquired craniocervical junction abnormality, where the tip of the odontoid process projects above the foramen magnum
- Aka. Atlantoaxial impaction or vertical cranial settling
- Extension of the odontoid process above Chamberlain’s line >3mm, or posterior to Wackenheim’s line, or < 30mm from the Height index of klaus indicates impression likely exists

TERMINOLOGY:
- Chamberlain’s Line (Palato-canal): Line between hard palate and posterior edge of foramen magnum (Opisthion)
- Wackenheim’s Clivus-Canal line: Extension of clival line through foramen magnum
- McGregor Line: From posterior margin of the hard palate to the Lowest point of the occipital squamosal surface
- McRae line: From basion to opisthion
- Height Index of Klaus: Line drawn from the tuberculum sellae to the internal occipital protuberance. The vertical distance between this line and the apex of the odontois is the height index of klaus
- Interlaminar spinous line/Spinolamellar line: Line drawn from interoccipital ridge above and down along the fused spinous process of C2/3, and also intersect posterior arch of atlas (C1; the axis is C2). If atleas if sued, posterior arch is anterior to the line, and therefore posterior compression of spinal cord occurs

Basilar Invagination: https://www.childrenshospital.org/sites/default/files/media_migration/c2917e49-4c46-4b10-be27-f3b943c61cb1.png

Vancouver 259

Chamberlain: https://prod-images-static.radiopaedia.org/images/23621379/e620bcb852a4b1ad176210994ccbb8_gallery.jpeg

McGregor: https://www.researchgate.net/profile/Mehmet-Bilgin-Eser/publication/330970865/figure/fig2/AS:724140680019971@1549660000957/Scheme-Demonstrates-differences-between-Chamberlain-line-from-McGregor-line.ppm

Klaus: https://ars.els-cdn.com/content/image/3-s2.0-B9780750613613500082-f02-08-9780750613613.gif

Spinolamellar: https://radiologykey.com/wp-content/uploads/2016/07/C11-FF4-4.gif

Question 17

Signs and symptoms of basilar invagination (name 5)

Answer 17

SIGNS/SYMPTOMS:
1. Headache (usually pain in back of head or upper neck)
2. Neck weakness
3. Nystagmus
4. Trouble talking or swallowing
5. Dizziness
6. Numbness/tingling in hands/feet
7. Loss of proprioception
8. Shock sensation down back with neck flexion (L’Hermitte’s)
9. Weakness/extremity paralysis
10. Urinary or fecal incontinence

Question 18

Etiologies of basilar invagination, name 6

Answer 18

ETIOLOGIES:
1. Cretinism (hypothyroidism)
2. Rheumatoid arthritis
3. Rickets (the softening and weakening of bones in children, usually because of an extreme and prolonged vitamin D deficiency)
4. Osteomalacia
5. Osteogenesis Imperfecta (Van Der Hoeve Syndrome)
6. Paget’s disease

CRROOP

Question 19

Regarding Cerebellar ataxia syndromes, discuss:
1. What is Ataxia?
2. What is the nystagmus typically associated with these syndromes? What other eye movements might they get? List 3 total
3. List 8 different types of Cerebellar ataxia

Answer 19

ATAXIA:
- Loss of coordination of muscle movements

NYSTAGMUS PATTERNS:
- Abnormal nystagmus including gaze-paretic nystagmus and rebound nystagmus is common
- Down beating nystagmus
- Hypermetric saccades / eye movements

TYPES OF CEREBELLAR ATAXIA SYNDROMES:
1. Paraneoplastic cerebellar degeneration
2. Familial Episodic Ataxia
3. Ataxia Telangiectasia
4. Spinocerebellar atrophy
5. Cerebellar atrophy (Dandy-Walker/Chiari 4)
6. Alcoholic Cerebellar degeneration
7. Refsum’s Disease
8. Friedreich’s ataxia

PET SCARF
Paraneoplastic cerebellar degeneration
Familial episodic ataxia
Ataxia telangiectasias
Spinocerebellar atrophy
Cerebellar atrophy
Alcoholic cerebellar degeneration
Refsum’s disease
Friedrich’s ataxia

Question 20

Regarding Paraneoplastic Cerebellar degeneration, discuss:
1. What is it caused by?
2. What are the most common associations?

Answer 20

PARANEOPLASTIC CEREBELLAR DEGENERATION:
- Due to anti-Purkinje cell antibodies in patients with undiagnostic and otherwise asymptomatic malignancies
- Purkinje cells = neurons specific to the cerebellar cortex

ASSOCIATIONS:
1. Small cell carcinoma of the lung
2. Breast cancer
3. Ovarian cancer
4. Cancer of the female genital tract
5. Autoimmune mechanism

A Small Breast Genitals Ovaries

Question 21

Regarding Familial Episodic Ataxia, discuss:
1. What is the genetics/inheritance?
2. What are the clinical presentations?
2. What causes it? What are the triggers?
3. What are the treatments?

Answer 21

INHERITANCE:
- Autosomal dominant
- 8 different types, most frequent are EA1 and EA2, caused by mutations in KCNA1 and CACNA1A

CLINICAL PRESENTATION:
- Recurrent attacks of cerebellar dysfunction/ataxia and vertigo

CAUSE:
- Abnormal intracellular pH

TRIGGERS:
1. Stress
2. Exercise

TREATMENT:
1. EA1: Carbonic anhydrase inhibitors, phenytoin
2. EA2: Acetazolamide

Question 22

Regarding Ataxia Telangiectasia, discuss:
1. Inheritance
2. Presentation

Answer 22

INHERITANCE:
- Autosomal recessive

CLINICAL PRESENTATION:
- Slowly progressive cerebellar ataxia
- Telangiectasis of skin and conjunctiva
- Recurrent URTIs

Question 23

Regarding Spinocerebellar Atrophy, discuss:
1. What is the typical clinical presentation?

Answer 23

Cerebellar ataxia with extrapyramidal signs (e.g. bradykinesia, tremor, slow hesitant gait)

Question 24

What is Cerebellar Atrophy (Dandy-Walker/Chiari 4)?

Answer 24

Highly localized atrophy of the cerebellum

Question 25

What is alcoholic cerebellar degeneration?

Answer 25

Selective degeneration of the anterior vermis

Question 26

Regarding Refsum’s disease, discuss:
1. What is the cause?
2. What are the clinical features? 4
3. How is it managed?

Answer 26

CAUSE:
1. Phytanic acid storage disease (medium chain fatty acid)

CLINICAL FEATURES:
- Retinitis pigmentosa
- Polyneuropathy
- Cerebellar ataxia
- SNHL

Treatment:
Dietary modifications (decrease medium chain fatty acids - like a reverse chyle leak diet)

Question 27

Regarding Friedrich’s Ataxis, discuss:
1. What is the inheritance and genetics? What does it cause?
2. What is the epidemiology?
3. What are the clinical features? 4

Answer 27

INHERITANCE/GENETICS:
- Most common Hereditary Ataxia
- Autosomal Recessive
- Typically associated with a GAA repeat expansion in the frataxin gene (slowly progressive trinucleotide repeat disorder)

EPIDEMIOLOGY:
- Onset typically before 20yo, may be as late as 6th decade

CLINICAL FEATURES: “CIPS”
- Instability of gait
- Progressive hearing loss
- Cardiomyopathy
- Scoliosis

Question 28

Regarding Cerebellar Ataxia with Neuropathy and Vestibular Areflexia Syndrome (CANVAS), discuss:
1. What is the genetics and inheritance?
2. What are the 3 hallmark features?

Answer 28

GENETICS:
- RFC1 gene
- Autosomal recessive
- Late onset degenerative multisystem neurological disease

HALLMARK FEATURES: (It’s in the name!!)
1. Cerebellar Ataxia
- Saccadic smooth pursuit
- Nystagmus
- Limb ataxia
- Cerebellar dysarthria

2. Non-length-dependent sensory neuronopathy
   - Deficits of pin-prick sensation (most common) or other sensory modalities
   - Absent peripheral reflexes
3. Bilateral vestibulopathy
   - Bilateral abnormal VOR (e.g. bidirectionally abnormal head impulse test, abnormal dynamic visual acuity)

NOTE:
Doll’s eye reflex (Oculo-cephalic reflex) - can only occur if both cerebellar ataxia and bilateral vestibulopathy are present

Question 29

What type of eye movement is most common with progressive Supranuclear palsy

Answer 29

Cannot look up or down, then horizontal.

Problem with the “supranuclear” problem - ie. difficulty initiating the movement however VOR in tact. So if you do the head movement they will still have an intact VOR.

Types of people that can’t go downstairs cuz they fall cuz they can’t look down

Vertical affected first
Horizontal affected after