motor neuron disease / spinal muscular dystrophy

Motor Neurone Disease

2

3

MND

4

5

MND

•Progressive, degenerative disease•Incurable•Comparatively rare•Group of related diseases•Motor neurones are affected•Upper and lower limb weakness•Speech and swallowing difficulties•Breathing difficulties

6

• Over 40 (usual age between 50 and 70)• Men slightly more than women• 2 per 100 000• Cause remains a mystery

7

Different Types

• UMN + LMN - Amyotrophic Lateral Sclerosis• UMN only – Pseudobulbar Palsy

- Primary Lateral Sclerosis• LMN only – Progressive bulbar Palsy

- Progressive spinal muscular

atrophy• Madras type of MND

8

Amyotrophic lateral sclerosis (ALS) • Most common• Classical prototype of MND• Affects movement by attacking the nerves

connecting the spinal cord to the muscles • Sites: Upper and Lower motor neurones

affected in brain stem and cervical segment of spinal cord

• Lower brain stem cranial nerves (bulb) – Bulbar muscles

Cont…9

ALS cont…

• C8-T1 segments affected - Weakness and wasting of the limbs (esp. atrophy of small muscles of hand )

• The early symptoms :

– Fasciculations – diagnostic hallmark

(deltoid region and thenar region of

hands, tongue)

- slurred speech and stumbling

10

ALS cont…

• Late symptoms:

swallowing affected – nasal regurgitation • Does not usually affect the senses or the

bowels or bladder• Average life expectancy 2-5 years from onset

of symptoms• Death due to pneumonias/respiratory

paralysis

11

Pseudobulbar Palsy

• Also common• Pure UMN involvement in brain stem (cortico

nuclear/bulbar fibres)• Poor prognosis (as bulb invonved)• Difficulty in swallowing• Slurring dysarthria, emotional lability• Tongue contracted, spastic• DTR – brisk, Plantar –î, Gag reflex

-exaggerated• Bladder/bowel not affected

12

Primary Lateral Sclerosis

• Rare 0.5%• Affects only upper motor neurone in sp. Cord

(lateral column)• Mainly weakness in the lower limbs• Can get symptoms in the hands or slurred

speech• Life span could be normal• Can develop into ALS

13

Progressive bulbar palsy

• Quarter of people• Lower motor neurones involved• Anterior horn cells in spinal cord affected• Slurring speech/difficulty swallowing• Life expectancy between 6 months and 3

years from diagnosis

14

Progressive Spinal Muscular Atrophy/Dystrophy

• Small number of people 5%• Lower motor neurones• Sometimes slower progression• Early symptoms are sometimes weakness and

clumsiness in the hands• Extensive fasciculations• Most people live for more than 5 years from

diagnosis

15

Madras type MND

Synonym: Juvenile type MND

Special features:•Young age (in 20s)•8th cr nerve – affected (sensorineural deafness)•May be in family

16

D/D

Fasciculations– •Benign fasciculation•Poliomyelitis•Acute fasciculations – organo-phosphorus poisoning

ALS – •Compressive myelopathy (C. spondylosis)

17

Investigations

EMG –

Denervation pattern with abnormal

spontaneous activity

18

Treatment- Mainly symptomatic and rehabilitative

treatment-Respiratory support

A new drug – Riluzole•Anti-glutamate action•Decreases increased excito-toxic action of glutamate in MND (ALS)•Slows down the progress by a few months•However, not very promising

19

Medications for symptoms:•Muscle cramps – Carbamazepine and Phenytoin•Muscle Stiffness – Muscle relaxants

Botox and intrathecal baclofen•Drooling – Hyoscine, Glycopyrrolate, atropine •Pain – usual analgesia/Gabapentin•Gastrostomy 20

Secondary MND

• C. spondylosis• Poliomyelitis (monomelic MND)• Paraneoplastic syndrome• Hyperthyroidism

21

22