arm weakness

Arm Weakness: Symptoms, Causes, Treatment

Different activities can trigger the causes of arm or muscle weakness. Some can be as simple as fatigue caused by overworking the muscles and arms, and other factors responsible for this medical condition can be life-threatening.

Generally, several misconceptions occur during diagnosis, and you can mistake arm weakness for muscle fatigue. Arm weakness is different from muscle fatigue because muscle contraction and relaxation don’t frequently occur due to damages in nerves that stimulate the movement of the muscles.

This means that you can expend so much energy in performing a task, yet there will be no response in the muscle. Specific muscles can be affected by arm weakness. What can cause this to happen?

Causes of Arm Weakness

Electrolyte disorders or imbalances

Electrolytes are important in regulating nerves and muscle functions. The essential electrolytes required for your body to undergo normal metabolism are sodium, calcium, potassium, and magnesium. They are supplied from the food and drinks you consume. An altered level of this essential electrolyte can trigger arm weakness.

Electrolyte disorders that can prompt arm weakness include hyperkalemic periodic paralysis or hypokalemia. Risk factors for electrolyte imbalance may include chemotherapy, poor diet, or loss of fluid through sweats and diarrhea.

Sleep disorders

Insomnia and other series of sleep disorders can cause fatigue, which leads to arm weakness. While several medical conditions can cause arm weakness, prolonged bed rest due to illness can bring about inactivity and degeneration of nerves in the muscles.


Muscles in the body lose their vigor, strength, and bulk with ageing. While this is a non-reversible natural phenomenon, it can be frustrating not to perform simple daily tasks as expected. Exercise is beneficial in increasing muscle strength. Balance is usually impaired with old age, so it’s important to avoid stressful exercise routines that can lead to trauma.


Infections are one of the common triggers of weakness in the arm. Infection can cause inflammation of muscles around the arms, causing weakness and discomfort that may last for a while. This condition can sometimes progress into chronic fatigue syndrome (CFS).

While any illness can be accompanied by inflammation of the muscles, certain illnesses are frequently diagnosed to cause chronic fatigue syndrome (CFS). They include HIV, hepatitis C, Lyme disease, and influenza.

Thoracic outlet syndrome

Thoracic outlet syndrome occurs due to compression of nerves and blood vessels traveling between the collarbone and ribs. Several symptoms may be accompanied by this condition, depending on the severity of the underlying condition.

Common symptoms of thoracic outlet syndrome include tingling, numbness, or weakness in the arms. Discoloration may also occur if blood vessels are compressed.

Symptoms that may occur with Arm Weakness

Symptoms of arm weakness vary depending on the severity of the underlying condition. Arm weakness symptoms include:

  • Fatigue
  • Reduced mobility
  • Muscle spasms
  • Tingling

You should report severe symptoms that may indicate a life-threatening condition to your doctor for a professional consultation.

Diagnosis for arm weakness

Early diagnosis of arm weakness is crucial to developing a suitable treatment course. Before treatment, your doctor will need to diagnose the underlying condition causing the discomfort. Your doctor will perform a physical examination to identify the possible site of injuries.

Your doctor may order the following test for proper diagnosis.

  • If your doctor suspects a broken bone is responsible for the weakness in your arms, he may order an MRI or CT for detailed imaging of your tissues and bones.
  • If your doctor suspects a heart condition is causing the condition, he may order a specific test to check blood flow through your heart.
  • A simple blood test may help diagnose other underlying diseases that may trigger arm weakness.

Treatment for arm weakness

Many forms of arm weakness may resolve independently without special treatment; however, a specific self-care routine can help relieve discomfort.

Pain Medication

In extreme cases where severe pain and discomfort, your doctor may prescribe a pain reliever like Tylenol to help ease discomfort.

Anti-inflammatory drugs

You can use anti-inflammatory drugs such as corticosteroids to reduce inflammation and pain.

Physical therapy

Physical therapy is more convenient to treat arm pain when there is a restricted range of motion.


Chronic conditions such as a torn ligament or fractured bone may require surgical operations to aid a quick recovery.

While there are several possible causes of arm weakening, most cases are reversible with proper diagnosis and treatment. If you experience localized, painful, and extreme discomfort for a prolonged time, visit a doctor as this might be a sign of a life-threatening condition.

Your doctor will offer guidance when a proper diagnosis is made and discuss a suitable treatment course for a quick recovery path.