neuropathy

Neuropathy, or peripheral neuropathy, refers to disorders of the peripheral nerves that connect the brain and spinal cord to the rest of the body. It can affect sensory, motor, and autonomic nerves. Neuropathy can involve many nerves (polyneuropathy), a single nerve (mononeuropathy), or a specific region of nerves (focal neuropathy). The most common form is distal symmetric polyneuropathy, often beginning in the feet and legs.

Causes are diverse. Diabetes mellitus is a leading preventable cause in many populations. Other etiologies include nutritional deficiencies (notably vitamin B12 and thiamine), chronic alcohol use, infections (such as HIV, hepatitis, Lyme disease, varicella-zoster), autoimmune diseases (including Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy), toxins and certain medications (such as some chemotherapy drugs), hereditary neuropathies (e.g., Charcot-Marie-Tooth disease), nerve compression injuries, and kidney or liver disease.

Symptoms depend on which nerves are affected. Sensory symptoms include numbness, tingling, burning or shooting pains, and reduced sensation. Motor symptoms can include weakness, cramps, and impaired balance or coordination. Autonomic involvement may cause lightheadedness with standing, abnormal sweating, digestive or bladder dysfunction, and sexual problems.

Diagnosis involves clinical assessment and neurological examination, supported by tests such as nerve conduction studies and electromyography. Other evaluations may include tests for diabetes, vitamin levels, kidney and liver function, infections, autoimmune markers, and imaging if a compressive lesion is suspected. Skin biopsy may be used for small fiber neuropathy.

Treatment aims to address the underlying cause when possible (for example, glucose control in diabetes or vitamin replacement) and to relieve symptoms. Neuropathic pain can be managed with medications such as anticonvulsants, antidepressants, topical agents, or other therapies. Physical therapy and safety measures are important, and prognosis varies with the cause and extent of nerve injury.