Peripheral Nerve Injuries: Mechanisms of Nerve Injury

Introduction

Peripheral nerve injuries (PNIs) result from damage to the nerves outside the brain and spinal cord. These injuries can lead to sensory and motor deficits, affecting a patient's quality of life.

Mechanisms of Nerve Injury

Compression Injuries

Chronic or acute compression of a nerve can cause ischemia and demyelination. Examples include carpal tunnel syndrome and thoracic outlet syndrome.

Traumatic Injuries

Physical trauma, such as lacerations or fractures, can damage peripheral nerves. These injuries can be classified into neuropraxia, axonotmesis, and neurotmesis based on severity.

Ischemic Injuries

Reduced blood supply to the nerve tissue can cause irreversible damage. This occurs in conditions like compartment syndrome.

Chemical and Toxic Injuries

Exposure to neurotoxic agents like lead, arsenic, or chemotherapy drugs can lead to nerve damage.

Inflammatory and Autoimmune Mechanisms

Diseases like Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy (CIDP) involve immune-mediated nerve destruction.

Clinical Manifestations

Patients may experience symptoms like paresthesia, weakness, muscle atrophy, and loss of reflexes.

Diagnosis and Treatment

Electromyography (EMG), nerve conduction studies, and imaging techniques aid in diagnosing PNIs. Management includes conservative approaches, surgical intervention, and rehabilitation.