Motor Neurone Disease
- Boot Camp
- Sep 17, 2023
- 0 min read
Physical Examination
Inspection
Atrophy of muscles, often asymmetric
Fasciculations, twitching of the muscle under the skin
Absence of foot drop (unlike in peripheral neuropathies)
Motor Examination
Tone
Lower motor neuron lesions may cause decreased or flaccid tone
Power
Lower motor neuron lesions often result in weakness in affected muscles
Reflex
Lower motor neuron lesions usually cause decreased or absent reflexes
Upper motor neuron signs, like brisk reflexes, may also be seen due to the combined upper and lower motor neuron involvement
Cerebellar Examination
Normal
Sensory Examination
Normal
Additional Examination if Required
Bulbar function examination: dysarthria and dysphagia may be present in bulbar onset motor neurone disease
Respiratory function examination: respiratory muscle weakness may occur in advanced stages
Investigations
Laboratory
Basic metabolic panel: to exclude other causes of symptoms such as electrolyte disturbances
Complete blood count: to rule out infection or malignancy
Creatine kinase: may be mildly elevated but non-specific
Thyroid function tests: to exclude hyperthyroidism which can mimic some symptoms
Vitamin B12 and folate levels: to exclude deficiencies which can cause neurological symptoms
Autoimmune screen: to exclude autoimmune diseases, like vasculitis, which can mimic MND
Imaging
MRI of brain and spine: to exclude other causes of neurological symptoms like tumors, multiple sclerosis, or spinal cord compression
CT chest/abdomen/pelvis: to rule out malignancies which can present with paraneoplastic neurological syndromes
Invasive
Lumbar puncture: to rule out infectious or inflammatory causes of neurological symptoms
Electromyography (EMG) and nerve conduction studies (NCS): can support the diagnosis of motor neurone disease by demonstrating active denervation and chronic reinnervation
Other Tests
Pulmonary function tests: to assess the extent of respiratory muscle involvement
Genetic testing: for known genetic mutations if familial motor neurone disease is suspected, for example SOD1, FUS, C9orf72, TDP-43
Swallowing studies: if bulbar symptoms are present to assess risk of aspiration
Speech and language therapy assessment: if bulbar symptoms are present to assess impact on communication
Management
General Management
Multidisciplinary team approach: involving neurologists, physiotherapists, occupational therapists, speech and language therapists, dietitians, and palliative care
Regular follow-up: to monitor progression and manage emerging symptoms
Psychological support: counseling for patient and family
Dietary advice: high-calorie diet to prevent weight loss
Medical Management
Riluzole: the only disease-modifying drug, potentially slows disease progression
Symptomatic control of spasticity: Baclofen or Tizanidine
Management of drooling: Glycopyrrolate or Botox injections
Management of emotional lability: Selective serotonin reuptake inhibitors (SSRIs) or tricyclic antidepressants (TCAs)
Surgical Management
Gastrostomy: for nutritional support in those with swallowing difficulties
Non-invasive ventilation: to manage respiratory failure
Other Management
Physiotherapy: to maintain mobility and manage spasticity
Occupational therapy: aids and adaptations to maintain independence
Speech and language therapy: for dysarthria and dysphagia, may include AAC devices
Palliative care: for symptom management and end-of-life care planning
Types of Motor Neurone Disease