motor neurone disease

Question 1

what are the different types of motor neurone disease?

Answer 1

• ALS - most common
• progressive bulbar palsy- which affects swallow and speech and has the worse prognosis
• progressive muscular atrophy- affects mostly the LMN
• primary lateral sclerosis- affects UMN especially in corticospinal tract

Question 2

what are the risk factors for motor neurone disease?

Answer 2

5-10% genetic
exposure to metals/ pesticides
smoking

Question 3

what are signs of lower motor neurone disease?

Answer 3

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

Question 4

what are signs of upper motor neurone disease?

Answer 4

Increased tone or spasticity
Brisk reflexes
Upgoing plantar responses

Question 5

what is the typical presentation?

Answer 5

• 60y/o man with increasing weakness and clumsiness

Question 6

what is the prognosis for motor neurone disease?

Answer 6

Most patients die within 3 years from the onset of their symptoms [5].

Poor prognostic factors include progressive bulbar palsy, old age and poor respiratory function [6].

The majority of patients die from respiratory complications.

Question 7

what investigations can be done for motor neurone disease?

Answer 7

• motor neurone disease is a clinical diagnosis but other investigations can be used to rule out other pathologies

Electromyography: in MND there will be evidence of fibrillation potentials

Nerve conduction studies: may show modest reductions in amplitude

MRI spine: imaging can help exclude spinal pathology which may mimic MND, such as cervical cord
compression and myelopathy

Pulmonary function tests: patients with MND are at risk of respiratory failure