Nerve compression syndrome

Nerve compression syndrome, or compression neuropathy, or nerve entrapment syndrome, is a medical condition caused by chronic, direct pressure on a peripheral nerve. It is known colloquially as a trapped nerve, though this may also refer to nerve root compression (by a herniated disc, for example). Its symptoms include pain, tingling, numbness and muscle weakness. The symptoms affect just one particular part of the body, depending on which nerve is affected. The diagnosis is largely clinical and can be confirmed with diagnostic nerve blocks. Occasionally imaging and electrophysiology studies aid in the diagnosis. Timely diagnosis is important as untreated chronic nerve compression may cause permanent damage. A surgical nerve decompression can relieve pressure on the nerve but cannot always reverse the physiological changes that occurred before treatment. Nerve injury by a single episode of physical trauma is in one sense an acute compression neuropathy but is not usually included under this heading, as chronic compression takes a unique pathophysiological course. Upper limb Lower limb, abdomen and pelvis Symptoms vary depending on whether the affected nerve contains motor and/or sensory fibers. Sensory nerve entrapment presents with paresthesias. These paresthesias may be painful, such as shooting pain, burning, or a dull ache. They may also be pain-free, such as numbness or tingling. Motor nerve entrapment may present with muscle weakness or paralysis for voluntary movements of the innervated muscles. Entrapment of certain pelvic nerves can cause incontinence and/or sexual dysfunction. Positive sensory symptoms are usually the earliest to occur, particularly tingling and neuropathic pain, followed or accompanied by reduced sensation or complete numbness. Muscle weakness is usually noticed later, and is often associated with muscle atrophy. The distribution of symptoms is highly specific to the nerve entrapped and the way the nerve courses and branches beyond the entrapment point.