What is sensory loss? Patients presenting to the emergency department (ED) with new onset of sensory alteration or loss are a challenge to the emergency physician. Causes range from serious to imagined, and from benign to life-threatening. Loss is used in this article to imply any alteration of sensation. The designation of new-onset is often relative; every patient notices a problem, even a chronic one, first at one point; this may precipitate a visit to their physician or an ED.

Patients' terminology is inexact and by its nature subjective. Seldom does a patient use the word loss; more typically the hand will be numb or feel dead. Some patients actually describe the altered sensation as weakness when true motor strength is intact and the only alteration is in sensory perception. The topic of this article is alteration of the somatosensory functions—pain, temperature, position and vibration, and light pressure. Special sensory alterations such as visual loss or hearing loss are not discussed. Anesthesia or analgesia are terms used technically to describe complete absence of sensation. Hypesthesia or hypalgesia refer to diminished sensation. Paresthesia is the term that describes the commonly articulated complaint of “pins and needles.” Dysesthesias technically refer to other unpleasant sensory alterations such as burning or cold. Hyperesthesia or hyperalgesia refer to abnormally increased or exaggerated sensations.<sup>1 Bates B. The nervous system A Guide to Physical Examination and History Taking Philadelphia: JB Lippincott (1987).  947

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The differential diagnosis of sensory alteration is vast, but attention here is devoted to conditions that might be encountered in an emergency medicine practice or to conditions that are particularly illustrative of key clinical findings. Many disorders of the nervous system include sensory alteration as part of a constellation of symptoms; other symptoms may predominate. A useful approach is to separate complaints with sensory alteration alone from those with accompanying motor symptoms and signs.<sup>14 Wagner J.H. Muscle weakness and sensory abnormalities Neurologic Disorders of Ambulatory Patients Philadelphia: Lea & Febiger (1989).  136

Cliccare qui per andare alla sezione Riferimenti</sup> Often, the presence of signs such as subtle weakness or reflex abnormalities are important in the anatomic location of the problem.