MOTOR NEURON DISEASE / SPINAL MUSCULAR DYSTROPHY

1. Motor Neurone Disease

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4. MND
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6. 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
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7. • Over 40 (usual age between 50 and 70)
• Men slightly more than women
• 2 per 100 000
• Cause remains a mystery
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8. 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
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9. 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

10. 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
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11. 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
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12. 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 12

13. 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
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14. 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
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15. 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
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16. Madras type MND
Synonym: Juvenile type MND
Special features:
•Young age (in 20s)
•8th
cr nerve – affected (sensorineural deafness)
•May be in family
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17. D/D
Fasciculations–
•Benign fasciculation
•Poliomyelitis
•Acute fasciculations – organo-phosphorus
poisoning
ALS –
•Compressive myelopathy (C. spondylosis)
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18. Investigations
EMG –
Denervation pattern with abnormal
spontaneous activity
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19. 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
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20. 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

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