Numbness and Tingling
Numbness and tingling are abnormal sensations that most often occur in the hands, feet, arms, and legs, though any part of the body can be affected. Multiple potential causes of numbness and tingling exist, including nerve injury, nerve compression (such as from a herniated disk in the spine), infections (including Herpes and shingles), and a lack of blood supply to a specific area due to hardening of the arteries or cold-induced injury (frostbite). Carpal tunnel syndrome (a condition in which the median nerve that runs through the wrist into the hand becomes compressed) can also cause significant numbness and tingling, as can a number of other medical conditions, including: diabetes, migraine, multiple sclerosis, seizures, stroke, underactive thyroid, and Reynaud’s phenomenon. In addition, numbness and tingling can be caused by low levels of calcium, potassium, or sodium, as well as vitamin B12 deficiency. Numbness and tingling can also be side effects of certain medications, as well as the result of alcohol or tobacco use.
Numbness is a common complaint among fibromyalgia patients (Wolfe et al., 1990; Wolfe et al., 1986; Yunus et al., 1981; Leavitt et al., 1986), with one study reporting its presence in over 80% of patients (Simms & Goldenberg, 1988). In a 2009 study of 166 fibromyalgia patients and 66 control subjects, researchers found that 50% of the fibromyalgia patients reported numbness in any part of the body (versus 3% of the control subjects). As for tingling, 54% of the fibromyalgia patients reported experiencing tingling in the arms or legs, versus only 4% of the control subjects. Furthermore, patients’ reports of both numbness and tingling were significantly supported by physical exam findings, including decreased response to vibration, temperature changes, and pinprick sensations (Watson et al., 2009).
The exact cause of numbness and tingling in individuals with fibromyalgia is unknown. Although it suggests a possible neurological (nerve) problem, fibromyalgia patients often have normal results on nerve conduction studies. Some researchers have suggested that numbness may be related to abnormal compression of the spinal cord in the cervical (neck) region. A 2004 study of 270 patients with fibromyalgia reported that, among a variety of other neurological symptoms, 69% experienced numbness. Various neurological and imaging tests performed during the study allowed the researchers to conclude that many patients who have fibromyalgia also have signs and symptoms consistent with cervical spinal cord compression (e.g., numbness). As a result, the authors suggested that fibromyalgia patients who exhibit neurological symptoms receive an evaluation for spinal cord compression, which is potentially treatable with surgery (Heffez et al., 2004).
For fibromyalgia patients who have a known co-morbid condition, such as underactive thyroid or Reynaud’s phenomenon, or other conditions such as carpal tunnel syndrome, diabetes, or multiple sclerosis, it is likely that the numbness/tingling may be a result of the underlying condition. As a result, treating the underlying or co-morbid condition is the best approach to relieving the numbness and tingling.
Despite these known associations, symptoms such as numbness and tingling can be difficult to attribute to any one particular cause, especially when multiple potential causal factors are present. This is one instance where dedicated and diligent tracking of fibromyalgia symptoms and treatments can help to unravel the mystery. Maintaining an accurate log of current treatment methods and noting any symptoms that occur during treatment, such as numbness and tingling, may help to identify if numbness and tingling are actually side effects of a specific medication or other therapy. When such relationships are identified, patients can work together with their doctor to determine the underlying cause and/or modify treatment strategies in order to relieve symptoms.