Motor Neuron Disease

Question 1

What is motor neuron disease?

Answer 1

Untreatable and rapidly progressive neurodegenerative disease = mainly clinical diagnosis, variable clinical phenotypes

Question 2

What are the main features of motor neuron disease?

Answer 2

Muscle weakness
Cognitive impairment
Issues with speech, swallow or breathing
UMN and/or LMN signs without sensory problems

Question 3

What is the progression of motor neuron disease?

Answer 3

Focal onset and continuous spread = results in generalised paraesthesiae
Median survival is 3 years

Question 4

What is the most common subtype of motor neuron disease?

Answer 4

Amyotrophic lateral sclerosis = worst prognosis and has mixed UMN and LMN signs, less common in non-Caucasians

Question 5

What is the epidemiology of motor neuron disease?

Answer 5

Slightly more common in men
90% sporadic and 10% familial
Sporadic peaks at age 50-75 (declines after age 80)

Question 6

What is the genetic occurrence of motor neuron disease?

Answer 6

Genetic aetiology has been identified in up to 20% of sporadic and 60% of familial cases

Question 7

What are the different kinds of motor neuron disease?

Answer 7

Primary lateral sclerosis
Progressive muscular atrophy
Progressive bulbar palsy

Question 8

What are some features of primary lateral sclerosis?

Answer 8

Rarest subtype

Presents with mostly UMN signs

Question 9

What are some features of progressive muscular atrophy?

Answer 9

LMN variant of primary lateral sclerosis

Has variable prognosis

Question 10

What is progressive bulbar palsy?

Answer 10

Bulbar variant = mixed upper and lower motor neuron signs but only confined to mouth

Question 11

What are the UMN signs of motor neuron disease?

Answer 11

Pseudobulbar affect
Moderate weakness
Spasticity and hyperreflexia
Extensor plantar reflexes

Question 12

What are the LMN signs of motor neuron disease?

Answer 12

Severe weakness and muscle cramps
Fasciculations
Hypotonicity and hyporeflexia
Muscle atrophy

Question 13

What part of the body do most patients present with symptoms in?

Answer 13

The limbs = extremities (70%, upper>lower), bulbar (25%) and thoracic (2%)

Question 14

What signs are most prominent?

Answer 14

LMN signs

Question 15

What is motor neuron disease katabolism?

Answer 15

Increased metabolic rate = occurs in 40-50%

Question 16

What are some features of progressive bulbar palsy?

Answer 16

More common in women aged 60-80
Always generalises into ALS
Affects tongue, facial and pharyngeal muscles
May need early communicator and nutritional support

Question 17

What is split hand syndrome?

Answer 17

Preferential wasting of thenar group = seen occasionally in ALS

Question 18

What mutation has been implicated in motor neuron disease?

Answer 18

C9orf72 expansion = present in 41% of familial ALS and 5-10% of sporadic ALS

Question 19

What are some variants of ALS?

Answer 19

Flail arm/leg syndrome = one limb affected
Focal distal spinal muscular dystrophy
All have more benign prognosis

Question 20

What is used to diagnose ALS?

Answer 20

Diagnosis of exclusion

Use neuroimaging and El Escorial criteria

Question 21

How is suspected motor neuron disease investigated?

Answer 21

Electrophysiology

Question 22

What is the underlying disease process of motor neuron disease?

Answer 22

Motor neuron degeneration and death

Question 23

What are some conditions motor neuron disease is misdiagnosed as?

Answer 23

Carpal tunnel syndrome, stroke and neuropathy

Question 24

How common are false positive diagnoses of motor neuron disease?

Answer 24

7-10% of cases

Question 25

What are some conditions which are mistaken for motor neuron disease?

Answer 25

Multifocal motor neuropathy, Kennedy's disease, myopathy, cervical spondylotic radiculomyelopathy

Question 26

What is an example of a drug used to treat motor neuron disease?

Answer 26

Riluzole = gives patient extra three moths at end of disease, needs blood monitoring as affects kidneys and liver

Question 27

Where are patients with motor neuron disease referred?

Answer 27

Specialist MND services = allocated to one consultant and two nurse specialists at time of diagnosis, seen 4-6 weekly if needed

Question 28

What is a poor survival indicator in motor neuron disease?

Answer 28

Weight loss > 10% at diagnosis

Question 29

How are communication difficulties managed?

Answer 29

Using AACs

Question 30

What are some features of a gastrostomy?

Answer 30

Either PEG, RIG, PIGG or NG used Carers may need to be involved in maintenance Narrow window for effectiveness

Question 31

What are some treatments for sialorrhoea?

Answer 31

Hyoscine or buscopan orally Glycopyrronium if cognitive impairment Botox and suction also options

Question 32

How are muscle cramps treated?

Answer 32

Quinine or baclofen

Question 33

How are muscle spasms treated?

Answer 33

Baclofen, tizanidine, dantrolene or gabapentin

Question 34

What is one of the main causes of death in motor neuron disease?

Answer 34

Weakness of respiratory muscles = treated with non-invasive ventilation, BiPAP commenced at night initially and gradually increased

Question 35

What is cognitive impairment associated with?

Answer 35

Frontotemporal dementia

Question 36

How does cognitive impairment present in motor neuron disease?

Answer 36

Apathy, disinhibition, poor planning/decision making, inappropriate laughing or crying

Question 37

What are some respiratory red flags?

Answer 37

SOB, orthopnoea, recurrent chest infections, disturbed or non-refreshed sleep, nightmares, daytime sleepiness, poor concentration