Numbness is often associated with other symptoms such as tingling (pins-and-needles), weakness, pain, difficulty walking, and increased risk of falls. When a person experiences complete numbness (anesthesia), delayed reaction to harmful situations such as deep cuts or exposure to hot temperatures can be dangerous. You must always remain vigilant.
What causes numbness?
Sensory information travels along nerve pathways. Disruption anywhere along these pathways can cause numbness or other sensory alterations. Common causes of numbness include demyelinating disorders such as multiple sclerosis, strokes, vasculitis, nerve compression, infections, vitamin deficiency, toxins or drugs, diabetes, or hereditary neuropathies.
How is numbness clinically evaluated?
Because there are so many possible causes of numbness, evaluation is done methodically. The doctor must determine which part of the nervous system is involved. Then, the doctor takes a thorough medical history to determine a differential diagnosis (ie, possible cause). Describe the numbness; when did it start; how long does it last; where is it located; are there other neurologic symptoms; do you suspect a possible cause such as recent trauma or infection?
A review of systems will help to identify other symptoms of disorders that may explain the numbness. Examples include back or neck pain (caused by arthritis or spinal cord compression), fever or rash (infectious neuropathy), joint pain (rheumatic disorders), headache (brain tumor or stroke), undernutrition (vitamin B12 deficiency), or excessive consumption of high-mercury seafood (polyneuropathy).
Past medical history is considered, as well as family history of neurologic disorders. A complete neurologic exam helps to determine the location and extent of the numbness and identify neurologic deficits in related reflex, motor, or sensory function. Testing may include laboratory tests, nerve conduction studies, magnetic resonance imaging (MRI), or CT scans.
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MS Signs & Symptoms: Numbness