neurologic disorders
Mononeuropathies
Causes of Mononeuropathies
Trauma is the most common cause of acute mononeuropathy and may occur as follows: Violent muscular activity or forcible overextension of a joint may cause focal neuropathy, as may repeated small traumas (eg, tight gripping of small tools, excessive vibration from air hammers). Prolonged, uninterrupted pressure at bony prominences can cause pressure neuropathy, usually affecting superficial nerves (ulnar, radial, peroneal), particularly in thin people; such pressure may occur during sound sleep, intoxication, bicycle riding, or anesthesia. Compression of nerves in narrow passageways causes entrapment neuropathy (eg, in carpal tunnel syndrome). Nerve compression by a tumor, hyperostosis, a cast, crutches, or prolonged cramped postures (eg, during gardening) may cause compression paralysis. Hemorrhage that compresses a nerve, exposure to cold or radiation, or direct tumor invasion may also cause neuropathy. Compression of a nerve may be transient (eg, caused by an activity) or fixed (eg, caused by a mass or anatomic abnormality). 