Clinical Approach to Neurologic Disorders

• GENERAL SYMPTOMS AND SIGNS

• TREATMENT

AnatomicPathophysiologicPhenomenologic

SymptomaticProtectiveCurativeSurgical

Surgical Approaches

• Ablative– thalamotomy– Pallidotomy

• Electrical stimulation (DBS) – VIM thalamus, globus pallidus internus, sub-thalamic nucleus

• Transplant– autologous adrenal, human fetal, xenotransplants, genetically

engineered transplants

Medtronic DBS system

Disease Classification

Congenital

Genetic

Demyelinating

Vascular

Immunologic

Neoplastic/ Para-neoplastic

To xic/ Nutritive

Metabolic

Mitochondrial/ Sub-cellular systems

Infectious/ Post-infectious

Traumatic

Degenerative

Idiopathic

Iatrogenic

Physical Exam

• Vital signs• Appearance• Emotional state

General medical Brief comments on relevant pulmonary,cardiovascular (murmurs, bruits),musculo-skeletal (deformities,asymmetries) and skin (rashes, othermarkings).

In neurology, asymmetric or focal findings are typically most important

Neurologic

Mental status orientation, level of alertness, speech, memory,cognitive state (mini-mental exam is helpful).

Cranial nerves I important really if asymmetric, particularly with achange in personality or suspected frontal lobe disease.II - fundus exam, visual acuity (should be documented),visual fields, and relative afferent pupillary defect(RAPD).III, IV and VI - pupil and eye movements, optokineticnystagmus (OKN), other forms of nystagmus andrelated findings.V sensory: cornea, skin to vertex of head, not angleof mandible.

motor: muscles of mastication (chewing).VII should clarify peripheral vs central issues.VIII important in hearing, balance. IX - XII - speech quality, swallowing, tonguemovements, tongue atrophy.

Physical Exam

Physical Exam

Motor examStrength e.g. MRC 5/5 point scaleMuscle massToneReflexes deep tendon (can be elicited in the jaw)

cutaneous (Babinski, abdominals)Rapid alternating movements speed, decrement rhythmInvoluntary movements

tremormyoclonuschoreaathetosisticsdystoniaballismusdyskinesia

Motor apraxiasdressing, combing hair, brushing teeth

Physical Exam

Sensory exam

Cranial divisions of V

Other head and neck Angle of jawSpinal levelsNerve or root

Primary modalities Light touchTwo point discriminationPainVibrationPosition sense

Higher cortical modalitiesGraphesthesiaStereognosis

Physical Exam

CoördinationUsually, but not always, tests for cerebellar dysfunction

Targeted voluntary movementsfinger-to-noseheel-shin

Rapid alternating movementsfine hand, finger control

Gait and posture

Stride, stancetruncal sway, arm swing

Posturestooped, falling forward, backward

Freezingin doorson or off medicationat start of walking

Disorders of muscle tone

I. HYPERTONICITY

a. Upper motor neuron syndrome

1. Loss of strength - paresis or paralysis2. Loss of fine distal movements3. Spasticity

clasp-knife (velocity-dependent) toneincreased (velocity-dependent) deep tendon

reflexes4. Release of flexor reflex afferents, eg Babinski sign

b. Extrapyramidal rigidity

1. Plastic, lead-pipe, equally increased tone throughout2. Normal deep tendon reflexes3. No paralysis of movement

Disorders of muscle tone

II. HYPOTONICITY

a. Cerebellar disease - acuteb. Deep coma

III. GEGENHALTEN

Resistance to passive manipulation, unable to relax, confusion,

frontal lobe disease

Basal ganglia disease

NEGATIVE symptoms

a. Primary functional deficits -

1. Akinesia or bradykinesiaunderactivity or poverty of movement (hypokinesia)

2. Loss of postural reflexesfailure to make small adjustments walking, standing up, etc

3. Difficulty with rapid alternating movements

POSITIVE symptoms

b. Secondary effects -

1. Lead pipe rigidityincreased tone

2. Involuntary movements (hyperkinetic disorders or dyskinesias)tremordystoniachoreaathetosisballismakathisia

Basal Ganglia

• Subcortical forebrain structures connected to sensorimotor and limbic systems

• Crucial part of the “control circuitry” that allows for the smooth execution of voluntary movement

Basal Ganglia

• Multiple cortico-basal ganglia-thalamo-cortical circuits

• Help program and carry out motor plans

• Scale the amplitude and effort of the execution of tasks with relation to requirements

• Incorporate motivation and emotional drives

D1

SNc

D2

GPe

DA

+-

GABA -

Brainstem/spinal cord

Glu +

Glu +

Glu +

-GABASPDyn

STN

GABAEnk -

Ventralthalamus

GPi/SNr

GABA -

GABA -

Parkinson’s disease

D1

SNc

D2

GPe

DA

+-

GABA -

Normal

Glu +

Glu +

-GABASPDyn

STN

GABAEnk -

Ventralthalamus

GPi/SNr

GABA -

Brainstem/spinal cord

GABA -

Glu +

Cerebral cortex

Striatum

Cerebral cortex

Striatum

D1

SNc

D2

GPe

DA

+-

GABA -

Brainstem/spinal cord

Glu +

Glu +

Glu +

-GABASPDyn

STN

GABAEnk -

Ventralthalamus

GPi/SNr

GABA -

GABA -

Huntington’s disease

D1

SNc

D2

GPe

DA

+-

GABA -

Normal

Glu +

Glu +

-GABASPDyn

STN

GABAEnk -

Ventralthalamus

GPi/SNr

GABA -

Brainstem/spinal cord

GABA -

Glu +

Cerebral cortex

Striatum

Cerebral cortex

Striatum

Basal ganglia disease

Tremor♦ Rhythmic oscillation about a joint

1. Physiologi c and exaggerated physiologic

2. Rest (parkinsonia )n

3. Kinetic or action

4. Postural

5. Int ent ion (cerebellar)

6. Task-relat ed: writ ing tr emor, ortho st at ic tr emor

Dystonia♦ Sust ained and/ or semi-rhyth mic muscle spasms, oft en worse with a

part icular t ask or po stur e♦ Persist ent att itud e in ext remes o f po sit ion, eg hyper- f lexed or hyper-

ext ended♦ Irregular tr emors

♦ “ Occupat ional” cramps (w rit er’s c ramps, musician’ cramps, et c)

♦ Meige’s syndro me: blepharospasm and o ro- facial dyskinesias/ dysto nia.

Photo by James Parkinson from his paper "An Essay on the Shaking Palsy” 1817

Normal PD

Basal ganglia disease

Chorea♦ Rapi ,d arrhythmi ,c jerk , y equa l distally and proximally

Athetosis♦ Slow, sinuous movements

♦ Movement s fro m on e postur e to another

♦ Inability to kee p limb i n one position

Ballism♦ Wil ,d flingin g movements o f limbs

♦ Associated with lesio ns o f the subthalami c nucleus

Basal ganglia disease

Myoclonus♦ Shoc -k like fast muscle jerks - faste r than chorea, less sinuous th an tremor

♦ Irregular

♦ May hav e sensor y relationship

♦ Cortical, su -b cortical, spinal

♦ Unusual variants: palata l myoclonus

Tics♦ Stereotyp ed movements

♦ Simple, e g eye blinking, o r complex involving many bo dy regions

♦ Associated with “inner feeling” to releas e tension

♦ May be vocal, eg barkin , g sniffing

♦ Gilles de la Tourett e syndrome

Akathisia♦ restlessness

♦ unab le to sit fo r more than a few seconds

Neurologic Issues Relevant to Dentistry

Bell’s palsy

Inflammation of the facial (VII) nerve - weakness of all parts of theface – the forehead movements , eye closure, mouth movements.

Often is mistaken for a “stroke” with slurred speech except thatlanguage and cognitive functions are preserved.

Never results in double vision, can affect taste on one side of thetongue, can occur at any age, and can be preceded by pain in oraround the ear.

Bell’s palsy

Initial presentation After 6 months

Neurologic Issues Relevant to Dentistry

Disorders affecting the face, jaw, mouth and neck

• Trigeminal neuralgia• Temporo-mandibular joint disorders• Other facial pains• Jaw tremors• Bruxism• Tardive dyskinesia• Meige’s syndrome• Other oro-buccal facial dystonias• Torticollis

Other Neurologic Issues Relevant to Dentistry

Complications of anesthesia

♦ Coma

♦ Maligna nt hyperthermia

Malignant Hyperthermia

Sudden onset of high fever, muscle rigidity and autonomic signs.

♦ Temperature rise → 42 -4 3° C

♦ Tachypnea, tachycardia

♦ Los s o f brainstem reflexes

♦ Circulator y collapse

♦ Rigidit y in all muscles → high C K a nd myoglobinuria

♦ J aw clenching - unexpected after relaxation fro m anesthesia

♦ Anesthetic agents

halothanesuccinylcholineether

Malignant Hyperthermia

Pathogenesis: a. anesthesia lead to increase in O2 consumption

b. depletion of ATPc. muscles unable to relax (muscles require energy to relax)

Treatment: D/C anesthesia at first sign

IV dantrolene - inhibits Ca++ releaseCooling, hydration, sodium bicarbonate

Susceptible patients: Family history of anesthetic-related problemsMusculo-skeletal abnormalitiesShort stature, ptosis, high arched palate