Weakness

last authored:
last reviewed:

 

 

Introduction

 

paresis - moderate weakness

plegia - severe weakness

 

It can be difficult to determine UMN vs LMN in situations of acute weakness, as it can take time for signs to evolve

Upper Motor Neuron patterns:

• in the arm, extensors are the weakest:
  • deltoid, triceps, wrist and finger extensors, finger abductors
• in the leg, flexors are weakest:
  • psoas, hamstrings, ankle dorsiflexors
• spacticity follows the opposite pattern, with antigravity extensors kicking in

Peripheral neuropathy or motor neuron disease

• distal limbs, in a length dependent manner

Muscle/NMJ disease

• proximal limbs
• ocular, bulbar

 

 

The Case of...

return to top

 

 

Differential Diagnosis

Proximal weakness - can be due to steroids

return to top

 

 

History and Physical Exam

return to top

 

 

Investigations

return to top

 

 

Management

 

return to top

 

 

Pathophysiology

 

return to top

 

 

 

 

Resources and References

 

 

return to top

 

 

Topic Development

created:

authors:

editors:

reviewers:

 

 

return to top