Motor Neuron diseases - PowerPoint Presentation

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Motor Neuron diseasesSlide2

Classification

Lower motor neurons disorders:

-- Hereditary : Spinal Muscular Atrophy

-- Acquired:

Monomelic

focal and segmental spinal muscular atrophies

Multifocal motor neuropathies

Acute motor axonal neuropathy

Post polio syndrome

Post irradiation syndrome

--Infective disordersSlide3

Combined upper and lower motor neuron disorders:

Amyotrophic Lateral sclerosis:

Familial Adult onset

Familial juvenile onset

Sporadic

ALS plus syndromes like… ALS and

frontotemporal

dementia, Western Pacific ALS-Parkinsonism-dementia complex.Slide4

Upper Motor Neuron disorders

-- Primary Lateral sclerosis

-- The hereditary spastic paraplegias

--

Neurolathyrism

--

KonzoSlide5

Disorders of the bulbar motor system

-- Kennedy’s disease ( X linked

bulbospinal

neuropathy)

-- Brown-

Vialetto

–van

Laere

syndrome

-- Fazio-

londe

diseaseSlide6

Toxic disorders of the motor neuron

--

Neurolathyrism

--Heavy metal toxicity

-- Post irradiation motor neuron injury

-- Western Pacific ALS –Parkinsonism-dementia complexSlide7

Disorders of motor neuron over activity

-- Neuromyotonia

-- Stiff person syndrome

Miscellaneous motor neuron disorders

--

Endocrinopathies

-- Copper deficiency syndrome

-- Benign cramp fasciculation syndromeSlide8
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I) Lower Motor neuron DisordersSlide10

Hereditary: Spinal muscular atrophy: A group of genetically determined pure lower motor neuron disorders in which

degeration

of the anterior horn cells leads to progressive, symmetrical muscle weakness and wasting with sparring of sensations and absence of pyramidal tract affection

.Slide11

1) Proximal

autosomal

recessive SMA of childhood

TypeI

:

Werdnig

hoffman

disease:

Presents with severe

generalised

weakness,

hypotonia

at birth or by 6 months of age

Affected children never sit or walk

Usually die of respiratory insufficiency within 2 years

Type 2: Intermediate form: onset of muscle weakness before 18 months of age

-- patients can sit but cannot walk unaided.

-- survival limited to adolescenceSlide12

Type 3:

Kugelberg

-

Welander

disease:

-- Onset of weakness after 18 months

-- usually are able to stand and walk

-- may become wheelchair dependant by adulthood

-- life

expentancy

is normal

Type 4: Adult onset : is designated as type 4Slide13
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SMN ( survival motor neuron gene) is involved in transport of m-RNA in the axons of motor neurons. In an event of abnormality of the gene the protein synthesis required for the structural continuity of the axons is hampered.Slide24

A few variants of SMA:

--

Sinal

muscular atrophy with

pontocerebellar

hypoplasia

: Additional features are cortical blindness,

nystagmus

, mental retardation

--

Autosomal

recessive Distal SMA: Slow progressive involvement of distal extremities with variable age of onset.

Here there may be upper limb, lower limb or vocal cord predominance.Slide25
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In SMARD there may be slight sensory and autonomic nervous system involvementSlide27
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Congenital

nonprogressive

spinal muscular atrophy affecting the lower limbs

Scapuloperoneal

SMA:

-- muscular weakness in

scapuloperoneal

distribution

-- May be

myogenic

and

neurogenic

in origin

-- There have been evidences for neuronal degeneration, pure

myopathis

and combinations of pathologies.Slide30
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Drugs commonly used

Neuroprotective

agents: inhibition of endogenous cell death pathways

eg

:

Gabapentine

,

Riluzole

--

Thyrotropin

releasing hormone:

neurotrophic

effects on the anterior horn cells

Anabolic agents like

albuterol

have been used: improvement in muscle strength has been observed

Myostatin

inhibitor:

Myostatin

is a negative regulator of satellite cells thus comes in the way of mitosis.Slide35
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Muscle strengthening

Muscle extensibility

Orthotic care

Enviornmental

modification

Maintaining respiratory hygiene

Vocational trainingSlide50

Amyotrophic Lateral SclerosisSlide51

Also called the Lou Gehrig’s disease

Major loss of both Upper and Lower motor neurons

--- Anterior horn cells in spinal cord

--- Motor cranial nerve

neuclei

in Brainstem

leading to

Amyotrophy

----

Demyelination

and

Gliosis

of

Corticospinal

and

Corticobulbar

tracts due to degeneration of Betz cells in the Motor cortex … leading to lateral sclerosis.Slide52

Epidemiology

Mean age of onset: 57 years (50 -70 years of age)

90% cases are sporadic,

10% may be familial Slide53

Etiology Suggested

Toxicity due to abnormal levels of Magnesium, Copper,

alluminium

has been suggested

Deficiency of nerve growth factor

Viral origin

Mutation of Superoxide Dismutase gene on chromosome 21 in familial forms of ALS, leading to increase in toxic properties

Oxidative stress and aberration in the

exitotoxicity

pathways leading to cell deathSlide54

Diagnosis

EMG: fibrillations,

fasciculations

seen in the muscles at rest and large unit spikes with voluntary activity

In 70% of patients: elevated levels of

Creatinine

Phosphokinase

CSF and blood tests used only to rule out other conditions

Superoxide

Dysmutase

gene for the familial forms

NCS: normal distal conduction velocity, F wave abnormalities

MRI:

Wallerian

degeneration in

Corticospinal

and

corticobulbar

tracts Slide55

Differential diagnosis

Multiple sclerosis

Cervical

Myolopathy

Syringomyelia

Peripheral neuropathies

Other motor neuron diseasesSlide56

Clinical Features

Weakness and atrophy: in all 4 limbs, mostly progressing from distal to proximal

Fatigue, cramps

By the time the patient comes with complaints, motor neuron degeneration would have progressed

Bulbar symptoms occur later in the disease

Sensory and ANS symptoms absent….. Have been positive in a few cases with sensory evoked potential abnormalities picked up.Slide57

Bulbar symptoms include: tongue

faciculations,facial

and palatal weakness,..

Dysphagia

and

dysarthria

Occulomotor

neuclei

are almost always spared

Death is usually due to respiratory failure

Amyotrophic Lateral Sclerosis severity scale:

-- Lower extremity: Walking

-- Upper Extremity: ( Dressing and Hygiene)

-- Speech

-- SwallowingSlide58

Prognosis

Average survival post onset is 4 years.

A small number have lived for 15 to 20 years post onset.

Patients with initial involvement of respiratory and the bulbar muscles are known to have faster progression of the disease.

Prognosis may vary as drug therapies are developed.Slide59

Medical Management

Drugs under investigations include:

--

Gabapentin

: to decrease the synthesis of glutamate

-- Supplemental dosage of

Tocopherol

:

Vit

E an antioxidant and free radical scavenger

-- Insulin like growth factor (

rhIGF

-I)

--

Riluzole

: decreases the

presynaptic

release of Glutamate has been found to have positive effects on the length of survivalSlide60

Supportive therapy for clinical problems

Muscle relaxants for spasms and cramps like Quinine and

Baclofen

.

For

dysphagia

: Problems with management of their saliva.. Chocking, drooling, increased

viscocity

due to dehydration

-- Hydration, tablets containing

papain

and

bromelain

.

--

Anticholinergic

agents

-- sometimes surgical options like ligation of ducts, severing the parasympathetic supply to the salivary glands,

botox

, radiotherapySlide61

Dysarthria

: Palatal lift prosthesis to address

hypernasality

, abnormalities with volume and speed of speech,

-- speech therapy, breathing techniques.

-- Voice amplification systems

-- Home made point boards

-- Computer based communication based on single pointing, eye movements that translates written word into voiced wordsSlide62

Respiratory Management:

-- Weakness of diaphragm, intercostals, abdominals, other accessory muscles.

-- signs are

orthopneoa

, hypoventilation, weak ineffective cough

-- O2 saturation levels (

transcutaneously

measured)

-- Forced Vital capacity assessment in standing and supine.

Rx: Chest Pt: Breathing for energy conservation, Stretching to maintain the length of muscles, endurance and strength

traning

,

-- Oxygenation at 2L/min

-- Bi PAP at home

-- Home mechanical ventilation (

tracheostomy

may be neededSlide63

Physiotherapy management

Daily activity log :

-- Type of activity

-- What position are you in ( Lying,

sitting,standing,moving

)

-- Fatigue level ( 0-10)

-- Pain ( Location, intensity from 0 to 10)

Assessment of muscle tone, strength, endurance, tightness, respiratory function, pain, speech

Contextual factorsSlide64

Principles to be followed

Combine formal exercises with enjoyable physical activities

Activities with

oppurtunities

for social development and personal accomplishment

Strengthening for concentric rather than eccentric activities as eccentric can cause muscle damage which in

dennervated

muscles may not be reversed

Mderate

resistence

exs

programs as high resistance

donot

have an added advantage

Focus on

stengthening

stronger muscles as those with < antigravity strength have less chance of improving

Monitor muscle power for overwork weakness

Activity modifications should include periods of physical activity and rest.Slide65

Phase I ( Independent)

Stage 1: Mild weakness, But pt is ambulatory independent

Rx: Prevent disuse atrophy

Add strengthening, ROM

exs

.

Stage 2: Moderate selective weakness

Rx: Avoid contractures, orthotic support, Strengthening with caution, use adaptive equipment to facilitate ADLs

Stage3: Severe selective weakness, increased respiratory effort, easy

fatiguability

Rx: Chest PT, Wheelchair: modified for the patient, Head rest may be needed.\, add pleasurable activities.Slide66

Phase 2: ( Partially independent)

Stage 4: Shoulder

subluxation

, edema, \

Techniques to relieve pain, spasm, shoulder stability, over head slings for transitions

Stage 5: Wheelchair

dependance

complete, secondary skin changes, sever UL and LL weakness.

Techniques for

tranfers

taught to care givers, HMV,

Antipressure

mattresses, home modificationsSlide67

Phase III: Dependant

Bed ridden

Rx: For

dysphagia

: long spoons, feeding tubes,

gastrotomy

Suctioning

Speech amplification, eye pointing

Clearing of airways,

tracheostomy

care