Motor Neuron Disease

Exam Cram

• Motor Neuron Disease includes many subsets, ALS being the most common,

• Presents with progressive motor signs (no sensory!):  UMN and LMN, of note areflexia and fasciculations,

• Diagnosis: clinical (EMG most useful investigation)

• Management: supportive

Outline

Background

• Made famous by the ALS Ice Bucket challenge

Assessment

History

• Progressive upper & lower motor neuron symptoms without sensory involvement

• Reduce exercise tolerance, dropping objects

• Aged 20-60yrs

Examination

• UMN: hypertonia, hyper-reflexia

• LMN: weakness, hypotonia, hyporeflexia

Investigations

• Electromyography- fibrillation and fasciculations

• Nerve conduction studies- normal

Diagnosis

Diagnosis: clinical

Differentials: 

• Multiple Sclerosis (MS): sensory features

• Polymyositis: proximal muscle weakness & raised CK

Management

Acute & chronic

• Supportive

ALS: amyotrophic lateral sclerosis

Commonest type of motor neuron disease

Presentation: LMN weakness upper limbs

Pathology: anterior horn cells

References and Resources

Links

• Body systems: Nervous system

• Specialties: Neurology

Page written in 2024.