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Toggle: English / SpanishWeakness - Overview
Alternative Names
Lack of strength; Muscle weakness
Definition of Weakness:
Weakness is a reduction in the strength of one or more muscles.
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. For example, you may feel weak if you have infectious diseases such as mononucleosis and the flu.
- Objective means there is a measurable loss of strength noted during a physical exam.
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
- Reviewed last on: 8/8/2009
- Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
References
Griggs RC, Józefowicz RF, Aminoff MJ. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 418.
Barohn RJ. Muscle diseases. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 447.