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. 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
- Anemia
- Myasthenia gravis
- Poliomyelitis
Home Care
Follow prescribed therapy for treating the underlying cause of the weakness.
Call your health care provider if
Call your doctor if you have:
- Prolonged, unexplained weakness
- Sudden weakness, particularly when it is in one area and not accompanied by other complaints, such as fever
- Sudden weakness following a viral illness
- Weakness in one area of the body
Mononucleosis
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