Paresthesias: a practical diagnostic approach.

Paresthesias may be caused by central or peripheral nervous system abnormalities. Central nervous system-induced paresthesias are most commonly caused by ischemia, structural or compressive phenomena, infection, inflammation or degenerative conditions. Peripherally induced paresthesias can be caused by entrapment syndromes, metabolic disturbances, trauma, inflammation, connective tissue diseases, toxins, hereditary conditions, malignancies, nutritional deficiencies and miscellaneous conditions. Confirming the diagnosis and establishing an etiology may require appropriate laboratory and radiologic studies, or other studies. In most cases, the specific clinical syndromes associated with the paresthesias, coupled with the presenting neurologic findings, provide the physician with a framework for the diagnosis.