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Weakness

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Definition:

Weakness is a reduction in the strength of one or more muscles.

Alternative Names:

Lack of strength; Muscle weakness

Considerations:

Weakness may be generalized (total body weakness) or localized to only one area, side of the body, limb, or muscle. Weakness is more notable when it is localized. Localized weakness may follow a stroke , flare up of multiple sclerosis , or injury to a nerve.

Weakness may be subjective or objective.

• Subjective means you feel weak, but there is no measurable loss of strength.
• Objective means there is a measurable loss of strength noted during a physical exam.

A subjective feeling of weakness may be associated with infectious diseases such as mono and the flu .

Common Causes:

Measurable weakness may result from a variety of conditions including metabolic, neurologic, primary muscular diseases, and toxic disorders.

METABOLIC

• Addison's disease
• Hyperparathyroidism
• Low sodium or potassium
• Thyrotoxicosis

NEUROLOGIC

• Amyotrophic lateral sclerosis
• Bell's palsy
• Cerebral palsy
• Guillain-Barre syndrome
• Multiple sclerosis
• Pinched nerve (for example, caused by a slipped disk in the spine)
• Stroke

PRIMARY MUSCULAR DISEASES

• Becker muscular dystrophy
• Dermatomyositis
• Muscular dystrophy (Duchenne)
• Myotonic dystrophy

TOXIC

• Botulism
• Organophosphate poisoning ( insecticides , nerve gas)
• Paralytic shellfish poisoning

OTHER

• Anemia
• Myasthenia gravis
• Poliomyelitis

References:

Olney RK. Weakness, Disorders of Movement, and Imbalance. In Kasper DL, Braunwald E, Anthony S. Fauci AS, eds. Harrison’s Internal Medicine . 16th ed. New York, NY: McGraw-Hill; 2005.

• Review Date: 7/17/2007
• Reviewed By: Robert Hurd, MD, Professor of Endocrinology, Department of Biology, Xavier University, Cincinnati, OH, and physician in the Primary Care Clinic, Cincinnati Veterans Administration Medical Center, Cincinnati, Ohio. Review provided by VeriMed Healthcare Network.

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