Motor neurone disease

Question 1

Most common form of motor neurone disease

Answer 1

Amyotrophic lateral sclerosis (ALS) is the most common and well-known specific motor neurone disease

Question 2

Other important forms of motor neurone disease

Answer 2

Progressive bulbar palsy is the second most common form of motor neurone disease. It affects primarily the muscles of talking and swallowing.

Other types of motor neurone disease to be aware of are progressive muscular atrophy and primary lateral sclerosis.

Question 3

Is there a genetic component to motor neurone disease

Answer 3

There is a genetic component and many genes have been linked with an increased risk of developing the condition. Taking a good family history is important as around 5-10% of cases are inherited.

Question 4

Other risk factors for motor neurone disease

Answer 4

Increased risk with smoking, exposure to heavy metals and certain pesticides.

Question 5

Presentation of motor neurone disease

Answer 5

Insidious, progressive weakness of the muscles throughout the body affecting the limbs, trunk, face and speech.

The weakness is often first noticed in the upper limbs.

There may be increased fatigue when exercising.

They may complain of clumsiness, dropping things more often or tripping over.

They can develop slurred speech (dysarthria).

Question 6

Signs of lower motor neurone disease

Answer 6

Muscle wasting
Reduced tone
Fasciculations(twitches in the muscles)
Reduced reflexes

Question 7

Signs of upper motor neurone disease

Answer 7

Increased tone or spasticity
Brisk reflexes
Upgoing plantar responses

Question 8

Management of MND

Answer 8

Riluzole can slow the progression of the disease and extend survival by a few months in ALS. It is licensed in the UK and should be initiated by a specialist.

Edaravone is currently used in the United States but not the UK. Recent studies suggest it has the potential to slow the progression of the disease and it may come in to use in the future.

Non-invasive ventilation (NIV) used at home to support breathing at night improves survival and quality of life.

Question 9

Features of non-medical management of MND

Answer 9

Effectively breaking bad news
Involving the multidisciplinary team (MDT) in supporting and maintaining their quality of life
Advanced directives to document the patient’s wishes as the disease progresses
End of life care planning
Patients usually die of respiratory failure or pneumonia

Question 10

Features of amyotrophic lateral sclerosis

Answer 10

typically LMN signs in arms and UMN signs in legs

in familial cases the gene responsible lies on chromosome 21 and codes for superoxide dismutase

Question 11

Presentation of primary lateral sclerosis

Answer 11

UMN signs only

Question 12

Presentation of progressive muscular atrophy

Answer 12

LMN signs only
affects distal muscles before proximal
carries best prognosis

Question 13

Presentation of progressive bulbar palsy

Answer 13

palsy of the tongue, muscles of chewing/swallowing and facial muscles due to loss of function of brainstem motor nuclei
carries worst prognosis

Question 14

Respiratory care for MND

Answer 14

non-invasive ventilation (usually BIPAP) is used at night

Question 15

Features which may point to an alternative diagnosis as opposed to MND

Answer 15

doesn’t affect external ocular muscles
no cerebellar signs
abdominal reflexes are usually preserved and sphincter dysfunction if present is a late feature

Question 16

What might nerve conduction studies show in MND

Answer 16

The diagnosis of motor neuron disease is clinical, but nerve conduction studies will show normal motor conduction and can help exclude a neuropathy