Arm weakness is defined as a limited ability to move your arm because of decreased strength in a muscle, or a loss of strength in the arm. A weakness in right arm may happen suddenly, increasingly progress over time, be accompanied by muscle weakness in other body muscles, or might occur with other symptoms including arm pain. If you have right arm weakness, you may have suffered some arm injuries or it may indicate some health conditions.

10 Reasons Why You Have Weakness in Right Arm

1. Stroke

A stroke is the sudden death of brain cells due to lack of oxygen and are caused by rupture of an artery or blockage of blood flow to an artery in the brain. Sudden paralysis or weakness of an arm can be one of its symptoms, and a treatment used may include modified constraint-induced therapy (mCIT). This therapy helps improve the use and movement in the arm by restricting the use of a less affected part of your body. This forces you to use the weakened part of your body. Electrical stimulation can also be used to enhance sensory awareness, and strengthen a weakened arm.

2. Arm Injury

Arm injury refers to trauma or an injury that affects the arm. Fractures, strains and sprains are the more common types of arm injuries, and the nature and severity of acute injury symptoms may vary considerably depending on the injury involved. Minor arm trauma is commonly caused by overuse, or normal everyday wear and tear on the arm. Fortunately, most minor injuries will heal on their own, and pain medication along with resting the arm is all that is needed to promote healing and relieve symptoms.

3. Muscle Disorder

If the pain gets worse with repetitive movement while you are working or playing a sport, you may have tendinitis, or the inflammation of a tendon. If it is painful to grip an object, and it begins on the outside of your elbow radiating down your arm, you may have tennis elbow. The use of anti-inflammatory medication, such as ibuprofen, can relieve pain and reduce swelling, and the application of ice packs to the area while resting your arm may prove beneficial.

4. Nerve Compression

Nerve compression is a condition caused by radial nerve dysfunction in the arm. Any damage to the radial nerve leads to difficulty moving the arm, along with a sensation in the back of the arm. There may be some difficulty straightening the arm at the elbow, tingling, burning sensation, weakness in right arm, numbness, or decreased sensation. In most cases, people recover slowly on their own, and no treatment is needed. However in some cases, surgery to remove whatever is pressing on the nerve or to repair the nerve might help.

Other Uncommon Causes

5. Amyotrophic Lateral Sclerosis (ALS)

ALS is a type of a motor neuron disease that causes nerve cells to slowly deteriorate and die. ALS is characterized by the gradual deterioration and death of nerve cells forming part of a pathway from the brain or spinal cord to a muscle, causing symptoms such as weakness in arm, hand, feet, etc. Over time, all muscles under voluntary control are affected, and people eventually lose the ability to breathe without a ventilator. Many people with ALS usually die within 3 to 5 years from the beginning of symptoms due to respiratory failure.

6. Guillain-Barre Syndrome (GBS)

GBS is a disorder in which a person’s immune system attacks parts of the nervous system, causing symptoms such as weakness and tingling starting in feet or legs which may slowly progress to the upper body, resulting in weakness in right arm or left arm. These symptoms may increase in intensity until some muscles can’t be used at all. If severe, the person can become almost totally paralyzed, and is life threatening with the potential to interfere with breathing. Most individuals, however, have good recovery from even the most severe cases, although some may continue to have a certain degree of weakness.

7. Myasthenia Gravis (MG)

MG is a chronic auto-immune neuromuscular disease that affects the voluntary muscles of the body. MG is caused by a defect in the transmission of nerve impulses to arm muscles. The marker of MG is muscle weakness that worsens during periods of activity, but improves after periods of rest. Medications suppressing the production of abnormal antibodies are used to treat the disorder, which help improve neuromuscular transmission and increase muscle strength.

8. Polymyositis

Polymyositis is an uncommon inflammatory disease that causes muscle weakness and makes it difficult to lift objects, or to reach overhead. The exact cause of polymyositis is unknown, but the disease shares many characteristics with auto-immune disorders, in which your immune system mistakenly attacks your own body tissues. While there is no cure for polymyositis, treatments ranging from medications to physical therapy may improve muscle strength and function.

9. Parsonage-Turner syndrome (PTS)

PTS is not a common disorder and can be characterized by severe upper arm and shoulder pain followed by a distinct upper arm weakness. If you have PTS, the nerves that control your shoulder, arm, and hand become inflamed. PTS can often be treated with a combination of medication and physical therapy. However, in rare cases, your doctor may indicate that you need surgery for a weakness in right arm.

10. Monomelic Amyotrophy (MMA)

MMA is characterized by a progressive loss of motor neurons, the nerve cells in the brain and spinal cord, that are responsible for controlling voluntary muscles. It is characterized by weakness and atrophy in a single limb, usually a hand and arm. The cause is unknown in most cases, although there have been medical reports linking MMA to radiation or traumatic injury. There is currently no cure for MMA, and treatment involves muscle strengthening exercises, and training in hand coordination.

When to Worry

When a weakness in right arm is accompanied by the following symptoms, immediate emergency medical attention is required.

• Change in level of alertness or consciousness, unresponsive or passed  out
• Slurred or garbled speech
• High fever (more than 101 degrees F)
• Paralysis or inability to move a body part
• Sudden weakness, numbness, or tingling on one side of the body
• Vision changes or vision loss
• Intense headache