Hypothyroidism is a condition in which the thyroid gland doesn't produce enough thyroid hormone. It is a possible but not common cause of damage to nerves outside of the brain and spinal cord, known as peripheral neuropathy.
Peripheral nerves carry information to and from the brain and spinal cord and the rest of the body, such as your arms and legs. Peripheral neuropathy occurs when the peripheral nerves become damaged. Symptoms may include pain, a burning feeling, tingling or loss of feeling in the area affected by the nerve damage. It also may cause muscle weakness or loss of muscle control.
Long-term hypothyroidism that's not treated can cause peripheral neuropathy. The link between hypothyroidism and peripheral neuropathy isn't fully understood, but hypothyroidism can cause fluid retention that leads to swollen tissues. This can put pressure on peripheral nerves.
This most commonly occurs in the wrists. The nerve responsible for hand function goes through a "tunnel" of soft tissue. This soft tissue can swell and press on the nerve, resulting in carpal tunnel syndrome. However, most people with carpal tunnel syndrome don't have hypothyroidism.
See your healthcare professional if you have or suspect you have hypothyroidism and you're having troubling or painful symptoms in your arms or legs.
Treatment
Treatment of peripheral neuropathy due to hypothyroidism involves managing hypothyroidism and treating the resulting symptoms. This may include:
- Levothyroxine (Synthroid, Unithroid, others), a medicine for hypothyroidism that often improves the symptoms of neuropathy.
- Exercising and maintaining a healthy weight, which can help reduce stress on your body and strengthen your arms and legs.
- Wear wrist splints for carpal tunnel syndrome. A splint helps keep the wrist in a neutral position and reduce pain. Wrist splints can be worn as you treat hypothyroidism and wait for symptoms to resolve.