Muscle weakness

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at December 18, 2015
StartSymptomsMuscle weakness

Muscle weakness can affect any age group or population and is a symptom associated with several muscular, neurological, acute or chronic illnesses. Learn how to recognize dangerous signs and when to call a doctor as well as steps to take in prevention.


Definition & Facts

Muscle weakness is a condition that is characterized by the inability of the muscles to function at their full strength. Common symptoms that may accompany muscle weakness include fatigue, fever, flu-like symptoms, weight loss, paresthesia, depression, vomiting, and change in level if consciousness.

There are numerous medical conditions which can result in muscle weakness. This is a condition that can develop gradually or appear suddenly and severely. Muscle weakness can be a result of an infection, trauma, autoimmune disease, malignancy, or many other abnormal processes. This condition may be temporary or develop into a chronic condition. Diagnosing muscle weakness and its primary cause involves a thorough personal and family medical history, physical exam, and completion of a neurological exam. A variety of tests may be performed such as blood tests, urinalysis, lumbar puncture, and imaging tests such as x-ray, nuclear scans, CT scan, and MRI to afford an appropriate diagnosis.


Temporary muscle weakness may be a result of a sedentary lifestyle. Muscle weakness can also be the result of moderate trauma such as a strained or torn muscle. Certain life threatening conditions may cause muscle weakness such as severe dehydration, stroke, or spinal cord injury.

If muscle weakness develops suddenly and severely it may be related to a torn muscle or Bell's palsy. Muscle weakness that becomes chronic over an ongoing period of time may result from complications of a stroke or cerebral palsy. Certain neurologic diseases, conditions, or disorders can result in muscle weakness such as cerebral palsy, stroke, multiple sclerosis, or a prolapsed disc in the back. An autoimmune disease, such as myasthenia gravis affects nerve function resulting in muscle weakness.

Various muscular diseases, conditions, or disorders may affect the ability of muscles to perform such as muscular dystrophy and myotonic dystrophy. Muscle weakness can be caused by metabolic diseases including Addison's disease, hyperparathyroidism, and electrolyte imbalances. Other conditions that can result in muscle weakness include bed rest, muscle trauma, dehydration, anemia, malnutrition, viral infections, and bacterial infections.

When to see a doctor

In cases where muscle weakness develops suddenly, especially when only noted on one side of the body, immediate medical treatment should be sought as this may be a sign of a stroke. If muscle weakness occurs with severe abdominal pain, medical treatment should also be sought immediately as this may be a sign of botulism.

911 should also be called for emergencies when muscle weakness is accompanied with confusion, a change or loss of consciousness, sudden change in vision, severe abdominal pain, severe headache, and the inability to move a specific body part or paralysis. If currently being treated for muscle weakness and mild symptoms recur or persist, prompt medical treatment should be sought. All cases of muscle weakness need to be properly evaluated and diagnosed.

Therefore, new reports, even mild, should be reported to a healthcare provider. Even cases of muscle weakness related to sedentary lifestyle should be evaluated so appropriate interventions can be taken such as physical therapy or development of an exercise regime. As there are numerous causes of muscle weakness, upon developing this condition an appointment should be made as soon as possible with a healthcare provider. Failure to seek appropriate medical treatment can result in potential complications such as:

Treatment & Therapy

A treatment plan for muscle weakness is individualized and formulated after diagnosing the specific cause and can vary greatly among patients as the following are taken into consideration when developing a treatment plan:

  • The root cause
  • Presence of co-existing diseases or conditions
  • Age and medical history of the patient
  • Severity of muscle weakness

Treatment typically involves a multifaceted plan that addresses the root cause, helps in strength building, reduces the risk of developing complications, and helps patients live a normally active life. Generally, treatment may include adequate resting periods, adequate nutrition and hydration, and regular medical care. Programs such as physical therapy, occupational therapy, rehabilitation, or a regular exercise program may be recommended. In some cases, support devices such as orthopedic splints, crutches, canes, or walkers are needed to support weakened muscles and improve mobility.

Muscle weakness associated with bacterial infections is typically treated with antibiotics. If muscle weakness is related to conditions causing inflammation of the nervous system such as Bell's palsy, myasthenia gravis, and multiple sclerosis, corticosteroid medications may be prescribed. Anemia resulting in muscle weakness may require blood transfusions. In cases of muscle weakness related to dehydration or electrolyte imbalances, rehydration and electrolyte supplementation is necessary either orally or intravenously.

Certain electrolyte imbalances that may be treated depending on the individual include phosphorus, magnesium, potassium, and vitamin B12. Depending upon the root cause of muscle weakness, various medications may be used as a form of treatment. These vary widely and are disease/condition specific, hence, the need to identify the primary source causing the development of muscle weakness as soon as possible.

Prevention & Prophylaxis

Not all diseases and conditions can be prevented. Routine physical exams are recommended for prevention, especially among those who smoke or have high blood pressure. Benefits of a routine physical exam include screening for diseases, assessing the risk of future medical problems, and encouraging a healthy lifestyle. Living a healthy lifestyle is greatly important for the prevention of many diseases and conditions. A healthy lifestyle includes the following:

A healthy lifestyle is necessary to prevent the development of many conditions in those with sedentary lifestyles. In addition to adopting a healthy lifestyle, those who are sedentary may also be suffering from mental health issues so other appropriate prevention interventions may include psychotherapy, group support, and antidepressants. Anemia can be prevented by eating a vitamin rich diet including iron, folate, vitamin C, and vitamin B12.

Dehydration can be prevented with the adequate intake of fluids and foods that are high in water. These foods include many fruits and vegetables. Additional fluids may be necessary to prevent dehydration in circumstances such as illness, exercise, or a hot and humid environment. Maintaining good health by preventing infection involves limiting exposure to infection sources, adequate sanitation, and adequate hygiene. Muscle strains causing muscle weakness can be prevented by practicing good body mechanics.

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