Medical Mystery: Young woman experiences arm pain with numbness and tingling

Lisa is a 34-year-old licensed practical nurse at a major university hospital. Her job often requires transferring patients from their bed to a chair. While lifting a patient into a wheelchair, she had sudden severe pain in her right arm and numbness into her fingers. In the past, she had similar pain and numbness that would come and go with repeated lifting and overhead activity, but she never sought evaluation.

Lisa reported the incident to her supervisor and was sent to a worker’s compensation clinic, where she was told she experienced a muscle strain. She was prescribed anti-inflammatory medications and placed on restricted duty, and began physical therapy.

Despite six weeks of treatment, Lisa continued to have severe pain and numbness in her right arm and hand, which felt worse with use.

She was referred to me by the worker’s compensation clinic for evaluation with a presumed diagnosis of cervical radiculopathy — commonly referred to as a “pinched nerve” in the neck.

This condition can occur after lifting something heavy, and often is the result of a herniated disc. The disc acts as a shock absorber between the neck bones (vertebrae). Think of these structures as a jelly doughnut, with a doughy outside and fluid inside. The outer “dough” can tear and the “jelly” can ooze out onto nearby nerves, resulting in pressure and nerve inflammation. These nerves travel down the arm and, when affected, can potentially cause pain, numbness and weakness.

After obtaining her history, I performed a physical examination consisting of strength and reflex testing, checking the range of motion in her neck and shoulders, and assessing sensation. Lisa’s strength and reflexes were normal, though she had reduced feeling in the fingers of her right hand. Special tests that can reproduce pinched nerve pain were normal. An MRI of the cervical spine (neck) did not show any nerve compression or disc herniations.

X-rays were ordered and showed an “extra rib” on her right side attached to the lowest neck vertebra (C7) and a partial extra rib on her left. While this condition can be common and often asymptomatic, in Lisa’s case it helped confirm a diagnosis.

Given the normal MRI of the neck, the extra rib on the right side of the neck, and the pain and numbness in the arm and hand, I made the diagnosis of thoracic outlet syndrome (TOS).

TOS is a relatively uncommon cause of pain and numbness in the arm and hand. It can be caused by repetitive overhead activity and can be associated with having an “extra rib.” After the nerves come out of the cervical spine, they continue through muscles in the neck and past the collarbone. The nerves can get “pinched” or irritated in cases where an extra rib is present. There is often an extra band of tissue that may be present, making painful pinched nerves more likely to occur.

Veins and arteries also pass through the thoracic outlet — the ring formed by the top ribs, just below the collarbone — and can become compressed in some cases, resulting in swelling or reduced circulation. This is less common than the nerves being affected.

The treatment of TOS typically involves rest and avoiding things that make the symptoms worse, such as overhead activity. Taking anti-inflammatory medicines and performing physical therapy including stretching are also prescribed. If these approaches fail, surgery may be necessary to take pressure off of the nerves, often including removal of the extra rib and any tissue compressing the nerves.

Despite targeted physical therapy, anti-inflammatory medications and rest, Lisa continued to have pain and numbness in her right arm and hand. She was referred to a surgeon who removed the right extra rib and an extra band of tissue overlying the nerves.

Six weeks after the surgery, Lisa felt significant relief of her pain and numbness. She returned to work at full duty three weeks later.

Jeremy Simon is a physical medicine and rehabilitation specialist at Rothman Orthopaedics.