Motor Neuron Disease Motor Neuron Disease

Home , Monomelic amyotrophy, Motor neuron, Motor neuron disease, Progressive bulbar palsy

• Incidence: 2-4 per 100 000 • Onset: usually 50-70 years

• Pathology: – Degenerative condition – anterior horn cells and upper motor neurons in spinal cord, resulting in mixed upper and lower motor neuron signs

• Cause unknown – 10% familial (SOD-1 mutation) – ? Related to athleticism Presentation

• Several variations in onset, but progress to the same endpoint • Motor nerves only affected • May be just UMN or just LMN at onset, but other features will appear over time

• Main patterns: – Amyotrophic lateral sclerosis – Bulbar presentaion – Primary lateral sclerosis (UMN onset) – Progressive muscular atrophy (LMN onset) Questions

Wasting Classification

• Amyotrophic Lateral Sclerosis • Progressive Bulbar Palsy • Progressive Muscular Atrophy • Primary Lateral Sclerosis • Multifocal Motor Neuropathy • Spinal Muscular Atrophy • Kennedy’s Disease • Monomelic Amyotrophy • Brachial Amyotrophic Diplegia El Escorial Criteria for Diagnosis Tongue fasiculations

Amyotrophic lateral sclerosis

• ‘Typical’ presentation (60%+) • Usually one limb initially – Foot drop – Clumsy weak hand – May complain of cramps • Gradual progression over months

• May be some wasting at presentation • Usually fasiculations (often more widespread) • Brisk reflexes, extensor plantars • No sensory signs; MAY occasionally be mild symptoms

• Relentless progression, noticable over weeks/ months Bulbar MND

• Approximately 30% of cases • Onset with dysarthria, dysphagia • Bulbar and pseudobulbar symptoms

• On examination – Dysarthria – Tongue wasting, fasciculation – Brisk jaw jerk – May be other limb symptoms (but not always)

• Progression more rapid than ALS presentation • Worse prognosis (approx 2 years) Other presentations

• Primary lateral sclerosis (5%) – Pure UMN onset

• Progressive muscular atrophy (5%) – Pure LMN onset – May be ‘flail limb’ appearance

• Probably slightly better prognosis Progressive bulbar palsy Difficulty breathing Muscle weakness Motor neuron disease II Differential diagnosis

• Diagnosis is clinical – EMG/ imaging may help

• MND is fatal – exclude other, less severe/treatable conditions

– Multilevel cervical/ lumbar degerative changes • May cause myelopathy + LMN features and fasciculation • Usually have sensory symptoms – Benign fasciculation syndrome – Bulbar – cerebrovascular disease, MND

– Multifocal motor neuropathy – Hereditary spastic paraplegia – Kennedy’s disease (SMA) Investigations

• Clinical diagnosis

• Check CK – modest elevation

• Investigations often aimed at excluding other causes – Often MRI cervical/lumbar spine – May image brain

• NCS/ EMG show “chronic active denervation” in areas supplied by multiple nerve roots (note this pattern may be seen in one territory by radiculopathy)

• Tongue/ Sternomastoid EMG sometimes performed Treatment

• Riluzole – Glutamate antagonist – May extend left expectancy slightly (3-5 months on average)

– Low side effect profile • Occ nausea, fatigue • Can disturb LFTs (needs monitoring at onset)

– Expensive (?cost/ benefit)

• Palliative – Nutrition • Soft diet • ‘Chin tuck’ – Hyoscine (excessive secretions/salivation) – Opiates/ benzodiazepines MND dementia

• Proportion of patients develop frontotemporal dementia

– Flat affect – Disinhibition – Language disturbance/ dysphasia – Impaired ‘executive function’ Cervical spondylomyelopathy vs Motor neuron disease

• Flaccid weakness UL, shoulder girdle • Wasting of all small hand muscles • Inverted supinator • MyeloCT scan – spinal stenosis C4-C6 • EMG – denervation of UL muscles Motor Neuron Disease

• Look for signs • Differential diagnosis • Counselling

• Good luck