Radiculopathy, also commonly referred to as pinched nerve, refers to a set of conditions in which one or more nerves are affected and do not work properly (a neuropathy). Radiculopathy can result in pain (radicular pain), weakness, altered sensation (paresthesia) or difficulty controlling specific muscles. Pinched nerves arise when surrounding bone or tissue, such as cartilage, muscles or tendons, put pressure on the nerve and disrupt its function.In a radiculopathy, the problem occurs at or near the root of the nerve, shortly after its exit from the spinal cord. However, the pain or other symptoms often radiate to the  part of the body served by that nerve. For example, a nerve root impingement in the neck can produce pain and weakness in the forearm. Likewise, an impingement in the lower back or lumbar-sacral spine can be manifested with symptoms in the foot. The radicular pain that results from a radiculopathy should not be confused with referred pain, which is different both in mechanism and clinical features. Polyradiculopathy refers to the condition where more than one spinal nerve root is affected. Causes
Radiculopathy most often is caused by mechanical compression of a nerve root usually at the exit foramen or lateral recess. It may be secondary to intervertebral disk herniation (most commonly at C7 and then the C6 level), degenerative disc disease, osteoarthritis, facet joint degeneration/hypertrophy, ligamentous hypertrophy, spondylolisthesis, or a combination of these factors.
Shingles is more common among the elderly and immunocompromised; usually (but not always) pain is followed by appearance of a rash with small blisters along a single dermatome. It can be confirmed by quick laboratory tests. Acute Lyme radiculopathy follows a history of outdoor activities during warmer months in likely tick habitats in the previous 1–12 weeks. In the U.S., Lyme is most common in New England and Mid-Atlantic states and parts of Wisconsin and Minnesota, but it is expanding to other areas. The first manifestation is usually an expanding rash possibly accompanied by flu-like symptoms. Lyme radiculopathy is usually worse at night and accompanied by extreme sleep disturbance, lymphocytic meningitis with variable headache and no fever, and sometimes by facial palsy or Lyme carditis. Lyme can also cause a milder, chronic radiculopathy an average of 8 months after the acute illness. Lyme can be confirmed by blood antibody tests and possibly lumbar puncture. If present, the above conditions should be treated immediately.Although most cases of radiculopathy are compressive and resolve with conservative treatment within 4–6 weeks, guidelines for managing radiculopathy recommend first excluding possible causes that, although rare, require immediate attention, among them the following. Cauda equina syndrome should be investigated in case of saddle anesthesia, loss of bladder or bowel control, or leg weakness. Cancer should be suspected if there is previous history of cancer, unexplained weight loss, or low-back pain that does not decrease by lying down or is unremitting.