Weakness

Definition

Weakness is reduced strength in one or more muscles.

Alternative Names

Lack of strength; Muscle weakness

Causes

Weakness may be all over the body or in only one area. Weakness is more noticeable when it is in one area. Weakness in one area may occur:

You may feel weak but have no real loss of strength. This is called subjective weakness. It may be due to an infection such as the flu. Or, you may have a loss of strength that can be noted on a physical exam. This is called objective weakness.

Weakness may be caused by diseases or conditions affecting many different body systems, such as the following:

METABOLIC

BRAIN/NERVOUS SYSTEM (NEUROLOGIC)

MUSCLE DISEASES

POISONING

OTHER

Home Care

Follow the treatment your health care provider recommends to treat the cause of the weakness.

When to Contact a Medical Professional

Contact your provider if you have:

What to Expect at Your Office Visit

The provider will do a physical exam. Your provider will also ask you about your weakness, such as when it began, how long it has lasted, and whether you have it all the time or only at certain times. You may also be asked about medicines you take or if you have been ill recently.

The provider may pay close attention to your heart, lungs, and thyroid gland. The exam will focus on the nerves and muscles if the weakness is only in one area.

You may have blood or urine tests. Imaging tests such as x-ray or ultrasound may also be ordered.

References

Eyre AJ. Weakness. In: Walls RM, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 9.

Fearon C, Murray B, Mitsumoto H. Disorders of upper and lower motor neurons. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 97.

Selcen D. Muscle diseases. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 393.



Review Date: 7/25/2022
Reviewed By: Linda J. Vorvick, MD, Clinical Professor, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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