What is the cause of foot drop (peroneal nerve palsy)?

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From the Guidelines

Foot drop is typically caused by weakness or paralysis of the muscles that lift the foot, often due to nerve damage, particularly to the peroneal nerve. The condition can result from various factors, including peripheral neuropathy, which is a common complication of diabetes 1. Peripheral neuropathy can lead to decreased pain sensation and a higher pain threshold in the extremities, increasing the risk of skin breakdown, infection, and Charcot joint destruction with some forms of exercise.

Causes of Foot Drop

  • Nerve damage, particularly to the peroneal nerve
  • Peripheral neuropathy, often associated with diabetes
  • Muscle weakness or paralysis

Importance of Early Intervention

Early intervention is crucial for effective management of foot drop, as it can help prevent complications and improve outcomes 1. Individuals with peripheral neuropathy should wear proper footwear and examine their feet daily to detect lesions early. Anyone with a foot injury or open sore should be restricted to non–weight-bearing activities.

Management of Foot Drop

Treatment depends on the underlying cause but generally includes:

  • Physical therapy to strengthen muscles
  • Ankle-foot orthoses (AFOs) or braces to support the foot
  • Addressing the primary condition, such as managing diabetes and preventing further nerve damage
  • Proper footwear with good ankle support to prevent tripping and falls

Prognosis and Outcome

The prognosis varies, with some cases resolving completely with treatment of the underlying cause, while others may require long-term management 1. Seeking medical attention promptly when symptoms appear is crucial for effective management of foot drop.

From the Research

Causes of Foot Drop

The causes of foot drop, also known as peroneal nerve palsy, can be varied and complex. Some of the possible causes include:

  • Injury to the common peroneal nerve, which innervates ankle joint and foot extensors 2
  • Sciatic nerve injury 2, 3
  • Lumbar plexopathies 2, 4
  • L4/L5 radiculopathy 2
  • Central nervous system related neuropathies, such as anterior horn cell disease or brain tumor 2
  • Compartment syndromes of the lower leg 2
  • Neurological injuries, muscular dysfunction, nerve compression, or vascular compromise in critically ill patients 3
  • Central or peripheral lesions of the nervous system, resulting in neurogenic drop foot 5
  • Spinal cord compression, such as at the T12-L1 level, resulting in L5 nerve root compression 6
  • Lumbar degenerative diseases, such as degenerative lumbar disease 4

Types of Foot Drop

There are different types of foot drop, including:

  • Flaccid drop foot, which develops when the first motor neuron is damaged 5
  • Spastic drop foot, which develops when the second motor neuron is damaged and persists as a residual long-term complication after stroke in about 14% of patients 5
  • Acute bilateral foot drop, which is a rare pathologic phenomenon requiring additional investigation into the underlying cause of the presentation 6

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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